License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 14:07:57 +00:00
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/* SPDX-License-Identifier: GPL-2.0 */
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2005-04-16 22:20:36 +00:00
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#ifndef _LINUX_STRING_H_
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#define _LINUX_STRING_H_
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2023-10-03 11:59:53 +00:00
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#include <linux/array_size.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/compiler.h> /* for inline */
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#include <linux/types.h> /* for size_t */
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#include <linux/stddef.h> /* for NULL */
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2023-09-20 12:36:09 +00:00
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#include <linux/err.h> /* for ERR_PTR() */
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2020-12-16 04:43:50 +00:00
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#include <linux/errno.h> /* for E2BIG */
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2023-09-20 12:36:09 +00:00
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#include <linux/overflow.h> /* for check_mul_overflow() */
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2021-08-02 20:40:32 +00:00
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#include <linux/stdarg.h>
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2012-10-13 09:46:48 +00:00
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#include <uapi/linux/string.h>
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2005-04-16 22:20:36 +00:00
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2006-03-24 11:18:42 +00:00
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extern char *strndup_user(const char __user *, long);
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2009-03-31 22:23:16 +00:00
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extern void *memdup_user(const void __user *, size_t);
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2018-01-07 18:06:15 +00:00
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extern void *vmemdup_user(const void __user *, size_t);
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2015-12-24 05:06:05 +00:00
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extern void *memdup_user_nul(const void __user *, size_t);
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2006-03-24 11:18:42 +00:00
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2023-09-20 12:36:09 +00:00
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/**
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* memdup_array_user - duplicate array from user space
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* @src: source address in user space
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* @n: number of array members to copy
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* @size: size of one array member
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*
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* Return: an ERR_PTR() on failure. Result is physically
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* contiguous, to be freed by kfree().
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*/
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static inline void *memdup_array_user(const void __user *src, size_t n, size_t size)
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{
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size_t nbytes;
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if (check_mul_overflow(n, size, &nbytes))
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return ERR_PTR(-EOVERFLOW);
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return memdup_user(src, nbytes);
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}
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/**
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* vmemdup_array_user - duplicate array from user space
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* @src: source address in user space
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* @n: number of array members to copy
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* @size: size of one array member
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*
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* Return: an ERR_PTR() on failure. Result may be not
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* physically contiguous. Use kvfree() to free.
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*/
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static inline void *vmemdup_array_user(const void __user *src, size_t n, size_t size)
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{
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size_t nbytes;
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if (check_mul_overflow(n, size, &nbytes))
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return ERR_PTR(-EOVERFLOW);
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return vmemdup_user(src, nbytes);
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}
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2005-04-16 22:20:36 +00:00
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/*
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* Include machine specific inline routines
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*/
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#include <asm/string.h>
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#ifndef __HAVE_ARCH_STRCPY
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extern char * strcpy(char *,const char *);
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#endif
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#ifndef __HAVE_ARCH_STRNCPY
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extern char * strncpy(char *,const char *, __kernel_size_t);
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#endif
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2015-04-29 16:52:04 +00:00
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#ifndef __HAVE_ARCH_STRSCPY
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string: drop __must_check from strscpy() and restore strscpy() usages in cgroup
e7fd37ba1217 ("cgroup: avoid copying strings longer than the buffers")
converted possibly unsafe strncpy() usages in cgroup to strscpy().
However, although the callsites are completely fine with truncated
copied, because strscpy() is marked __must_check, it led to the
following warnings.
kernel/cgroup/cgroup.c: In function ‘cgroup_file_name’:
kernel/cgroup/cgroup.c:1400:10: warning: ignoring return value of ‘strscpy’, declared with attribute warn_unused_result [-Wunused-result]
strscpy(buf, cft->name, CGROUP_FILE_NAME_MAX);
^
To avoid the warnings, 50034ed49645 ("cgroup: use strlcpy() instead of
strscpy() to avoid spurious warning") switched them to strlcpy().
strlcpy() is worse than strlcpy() because it unconditionally runs
strlen() on the source string, and the only reason we switched to
strlcpy() here was because it was lacking __must_check, which doesn't
reflect any material differences between the two function. It's just
that someone added __must_check to strscpy() and not to strlcpy().
These basic string copy operations are used in variety of ways, and
one of not-so-uncommon use cases is safely handling truncated copies,
where the caller naturally doesn't care about the return value. The
__must_check doesn't match the actual use cases and forces users to
opt for inferior variants which lack __must_check by happenstance or
spread ugly (void) casts.
Remove __must_check from strscpy() and restore strscpy() usages in
cgroup.
Signed-off-by: Tejun Heo <tj@kernel.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ma Shimiao <mashimiao.fnst@cn.fujitsu.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
2018-01-09 15:21:15 +00:00
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ssize_t strscpy(char *, const char *, size_t);
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2015-04-29 16:52:04 +00:00
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#endif
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2019-04-05 01:58:58 +00:00
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/* Wraps calls to strscpy()/memset(), no arch specific code required */
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ssize_t strscpy_pad(char *dest, const char *src, size_t count);
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2005-04-16 22:20:36 +00:00
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#ifndef __HAVE_ARCH_STRCAT
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extern char * strcat(char *, const char *);
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#endif
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#ifndef __HAVE_ARCH_STRNCAT
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extern char * strncat(char *, const char *, __kernel_size_t);
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#endif
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#ifndef __HAVE_ARCH_STRLCAT
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extern size_t strlcat(char *, const char *, __kernel_size_t);
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#endif
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#ifndef __HAVE_ARCH_STRCMP
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extern int strcmp(const char *,const char *);
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#endif
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#ifndef __HAVE_ARCH_STRNCMP
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extern int strncmp(const char *,const char *,__kernel_size_t);
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#endif
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2007-03-29 08:18:42 +00:00
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#ifndef __HAVE_ARCH_STRCASECMP
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extern int strcasecmp(const char *s1, const char *s2);
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#endif
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#ifndef __HAVE_ARCH_STRNCASECMP
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extern int strncasecmp(const char *s1, const char *s2, size_t n);
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#endif
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2005-04-16 22:20:36 +00:00
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#ifndef __HAVE_ARCH_STRCHR
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extern char * strchr(const char *,int);
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#endif
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2014-03-14 17:00:14 +00:00
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#ifndef __HAVE_ARCH_STRCHRNUL
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extern char * strchrnul(const char *,int);
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#endif
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2020-02-04 01:37:20 +00:00
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extern char * strnchrnul(const char *, size_t, int);
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2005-04-16 22:20:36 +00:00
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#ifndef __HAVE_ARCH_STRNCHR
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extern char * strnchr(const char *, size_t, int);
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#endif
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#ifndef __HAVE_ARCH_STRRCHR
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extern char * strrchr(const char *,int);
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#endif
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2009-12-15 02:01:04 +00:00
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extern char * __must_check skip_spaces(const char *);
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2009-12-15 02:01:15 +00:00
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extern char *strim(char *);
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static inline __must_check char *strstrip(char *str)
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{
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return strim(str);
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}
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2005-04-16 22:20:36 +00:00
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#ifndef __HAVE_ARCH_STRSTR
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2010-01-14 02:53:55 +00:00
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extern char * strstr(const char *, const char *);
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#endif
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#ifndef __HAVE_ARCH_STRNSTR
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extern char * strnstr(const char *, const char *, size_t);
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2005-04-16 22:20:36 +00:00
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#endif
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#ifndef __HAVE_ARCH_STRLEN
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extern __kernel_size_t strlen(const char *);
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#endif
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#ifndef __HAVE_ARCH_STRNLEN
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extern __kernel_size_t strnlen(const char *,__kernel_size_t);
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#endif
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2006-04-11 05:53:57 +00:00
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#ifndef __HAVE_ARCH_STRPBRK
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extern char * strpbrk(const char *,const char *);
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#endif
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#ifndef __HAVE_ARCH_STRSEP
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extern char * strsep(char **,const char *);
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#endif
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#ifndef __HAVE_ARCH_STRSPN
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extern __kernel_size_t strspn(const char *,const char *);
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#endif
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#ifndef __HAVE_ARCH_STRCSPN
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extern __kernel_size_t strcspn(const char *,const char *);
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#endif
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2005-04-16 22:20:36 +00:00
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#ifndef __HAVE_ARCH_MEMSET
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extern void * memset(void *,int,__kernel_size_t);
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#endif
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2017-09-08 23:13:48 +00:00
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#ifndef __HAVE_ARCH_MEMSET16
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extern void *memset16(uint16_t *, uint16_t, __kernel_size_t);
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#endif
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#ifndef __HAVE_ARCH_MEMSET32
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extern void *memset32(uint32_t *, uint32_t, __kernel_size_t);
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#endif
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#ifndef __HAVE_ARCH_MEMSET64
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extern void *memset64(uint64_t *, uint64_t, __kernel_size_t);
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#endif
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static inline void *memset_l(unsigned long *p, unsigned long v,
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__kernel_size_t n)
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{
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if (BITS_PER_LONG == 32)
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return memset32((uint32_t *)p, v, n);
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else
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return memset64((uint64_t *)p, v, n);
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}
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static inline void *memset_p(void **p, void *v, __kernel_size_t n)
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{
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if (BITS_PER_LONG == 32)
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return memset32((uint32_t *)p, (uintptr_t)v, n);
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else
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return memset64((uint64_t *)p, (uintptr_t)v, n);
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}
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2018-10-05 12:43:05 +00:00
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extern void **__memcat_p(void **a, void **b);
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#define memcat_p(a, b) ({ \
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BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)), \
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"type mismatch in memcat_p()"); \
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(typeof(*a) *)__memcat_p((void **)(a), (void **)(b)); \
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})
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2005-04-16 22:20:36 +00:00
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#ifndef __HAVE_ARCH_MEMCPY
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extern void * memcpy(void *,const void *,__kernel_size_t);
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#endif
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#ifndef __HAVE_ARCH_MEMMOVE
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extern void * memmove(void *,const void *,__kernel_size_t);
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#endif
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#ifndef __HAVE_ARCH_MEMSCAN
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extern void * memscan(void *,int,__kernel_size_t);
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#endif
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#ifndef __HAVE_ARCH_MEMCMP
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extern int memcmp(const void *,const void *,__kernel_size_t);
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#endif
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2019-04-06 01:38:45 +00:00
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#ifndef __HAVE_ARCH_BCMP
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extern int bcmp(const void *,const void *,__kernel_size_t);
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#endif
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2005-04-16 22:20:36 +00:00
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#ifndef __HAVE_ARCH_MEMCHR
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extern void * memchr(const void *,int,__kernel_size_t);
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#endif
|
2017-05-29 19:22:50 +00:00
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#ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE
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static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
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{
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memcpy(dst, src, cnt);
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}
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|
|
|
#endif
|
x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()
In reaction to a proposal to introduce a memcpy_mcsafe_fast()
implementation Linus points out that memcpy_mcsafe() is poorly named
relative to communicating the scope of the interface. Specifically what
addresses are valid to pass as source, destination, and what faults /
exceptions are handled.
Of particular concern is that even though x86 might be able to handle
the semantics of copy_mc_to_user() with its common copy_user_generic()
implementation other archs likely need / want an explicit path for this
case:
On Fri, May 1, 2020 at 11:28 AM Linus Torvalds <torvalds@linux-foundation.org> wrote:
>
> On Thu, Apr 30, 2020 at 6:21 PM Dan Williams <dan.j.williams@intel.com> wrote:
> >
> > However now I see that copy_user_generic() works for the wrong reason.
> > It works because the exception on the source address due to poison
> > looks no different than a write fault on the user address to the
> > caller, it's still just a short copy. So it makes copy_to_user() work
> > for the wrong reason relative to the name.
>
> Right.
>
> And it won't work that way on other architectures. On x86, we have a
> generic function that can take faults on either side, and we use it
> for both cases (and for the "in_user" case too), but that's an
> artifact of the architecture oddity.
>
> In fact, it's probably wrong even on x86 - because it can hide bugs -
> but writing those things is painful enough that everybody prefers
> having just one function.
Replace a single top-level memcpy_mcsafe() with either
copy_mc_to_user(), or copy_mc_to_kernel().
Introduce an x86 copy_mc_fragile() name as the rename for the
low-level x86 implementation formerly named memcpy_mcsafe(). It is used
as the slow / careful backend that is supplanted by a fast
copy_mc_generic() in a follow-on patch.
One side-effect of this reorganization is that separating copy_mc_64.S
to its own file means that perf no longer needs to track dependencies
for its memcpy_64.S benchmarks.
[ bp: Massage a bit. ]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: <stable@vger.kernel.org>
Link: http://lore.kernel.org/r/CAHk-=wjSqtXAqfUJxFtWNwmguFASTgB0dz1dT3V-78Quiezqbg@mail.gmail.com
Link: https://lkml.kernel.org/r/160195561680.2163339.11574962055305783722.stgit@dwillia2-desk3.amr.corp.intel.com
2020-10-06 03:40:16 +00:00
|
|
|
|
2011-11-01 00:08:07 +00:00
|
|
|
void *memchr_inv(const void *s, int c, size_t n);
|
2023-06-05 17:05:52 +00:00
|
|
|
char *strreplace(char *str, char old, char new);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2015-02-13 22:36:24 +00:00
|
|
|
extern void kfree_const(const void *x);
|
|
|
|
|
|
2016-05-20 00:10:55 +00:00
|
|
|
extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
|
2015-02-13 22:36:24 +00:00
|
|
|
extern const char *kstrdup_const(const char *s, gfp_t gfp);
|
2007-07-18 01:37:02 +00:00
|
|
|
extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
|
2022-09-29 09:24:53 +00:00
|
|
|
extern void *kmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2);
|
2022-12-21 14:42:45 +00:00
|
|
|
extern void *kvmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2);
|
2017-07-04 16:25:02 +00:00
|
|
|
extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);
|
2005-06-23 07:09:02 +00:00
|
|
|
|
2007-07-18 01:37:02 +00:00
|
|
|
extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
|
|
|
|
|
extern void argv_free(char **argv);
|
|
|
|
|
|
2008-05-01 11:34:42 +00:00
|
|
|
extern bool sysfs_streq(const char *s1, const char *s2);
|
2016-03-17 21:22:14 +00:00
|
|
|
int match_string(const char * const *array, size_t n, const char *string);
|
2017-03-21 11:56:46 +00:00
|
|
|
int __sysfs_match_string(const char * const *array, size_t n, const char *s);
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* sysfs_match_string - matches given string in an array
|
|
|
|
|
* @_a: array of strings
|
|
|
|
|
* @_s: string to match with
|
|
|
|
|
*
|
|
|
|
|
* Helper for __sysfs_match_string(). Calculates the size of @a automatically.
|
|
|
|
|
*/
|
|
|
|
|
#define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s)
|
2016-03-17 21:22:14 +00:00
|
|
|
|
2009-03-06 16:21:46 +00:00
|
|
|
#ifdef CONFIG_BINARY_PRINTF
|
|
|
|
|
int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
|
|
|
|
|
int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
|
|
|
|
|
int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4);
|
|
|
|
|
#endif
|
|
|
|
|
|
2008-07-24 04:26:44 +00:00
|
|
|
extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
|
2014-08-27 03:16:35 +00:00
|
|
|
const void *from, size_t available);
|
2008-07-24 04:26:44 +00:00
|
|
|
|
2019-12-01 01:50:33 +00:00
|
|
|
int ptr_to_hashval(const void *ptr, unsigned long *hashval_out);
|
|
|
|
|
|
2009-03-31 19:05:36 +00:00
|
|
|
/**
|
|
|
|
|
* strstarts - does @str start with @prefix?
|
|
|
|
|
* @str: string to examine
|
|
|
|
|
* @prefix: prefix to look for.
|
|
|
|
|
*/
|
|
|
|
|
static inline bool strstarts(const char *str, const char *prefix)
|
|
|
|
|
{
|
|
|
|
|
return strncmp(str, prefix, strlen(prefix)) == 0;
|
|
|
|
|
}
|
2012-07-30 21:40:55 +00:00
|
|
|
|
2014-08-27 03:16:35 +00:00
|
|
|
size_t memweight(const void *ptr, size_t bytes);
|
2019-10-07 22:00:02 +00:00
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* memzero_explicit - Fill a region of memory (e.g. sensitive
|
|
|
|
|
* keying data) with 0s.
|
|
|
|
|
* @s: Pointer to the start of the area.
|
|
|
|
|
* @count: The size of the area.
|
|
|
|
|
*
|
|
|
|
|
* Note: usually using memset() is just fine (!), but in cases
|
|
|
|
|
* where clearing out _local_ data at the end of a scope is
|
|
|
|
|
* necessary, memzero_explicit() should be used instead in
|
|
|
|
|
* order to prevent the compiler from optimising away zeroing.
|
|
|
|
|
*
|
|
|
|
|
* memzero_explicit() doesn't need an arch-specific version as
|
|
|
|
|
* it just invokes the one of memset() implicitly.
|
|
|
|
|
*/
|
|
|
|
|
static inline void memzero_explicit(void *s, size_t count)
|
|
|
|
|
{
|
|
|
|
|
memset(s, 0, count);
|
|
|
|
|
barrier_data(s);
|
|
|
|
|
}
|
2012-07-30 21:40:55 +00:00
|
|
|
|
2012-12-18 00:01:18 +00:00
|
|
|
/**
|
|
|
|
|
* kbasename - return the last part of a pathname.
|
|
|
|
|
*
|
|
|
|
|
* @path: path to extract the filename from.
|
|
|
|
|
*/
|
|
|
|
|
static inline const char *kbasename(const char *path)
|
|
|
|
|
{
|
|
|
|
|
const char *tail = strrchr(path, '/');
|
|
|
|
|
return tail ? tail + 1 : path;
|
|
|
|
|
}
|
|
|
|
|
|
include/linux/string.h: add the option of fortified string.h functions
This adds support for compiling with a rough equivalent to the glibc
_FORTIFY_SOURCE=1 feature, providing compile-time and runtime buffer
overflow checks for string.h functions when the compiler determines the
size of the source or destination buffer at compile-time. Unlike glibc,
it covers buffer reads in addition to writes.
GNU C __builtin_*_chk intrinsics are avoided because they would force a
much more complex implementation. They aren't designed to detect read
overflows and offer no real benefit when using an implementation based
on inline checks. Inline checks don't add up to much code size and
allow full use of the regular string intrinsics while avoiding the need
for a bunch of _chk functions and per-arch assembly to avoid wrapper
overhead.
This detects various overflows at compile-time in various drivers and
some non-x86 core kernel code. There will likely be issues caught in
regular use at runtime too.
Future improvements left out of initial implementation for simplicity,
as it's all quite optional and can be done incrementally:
* Some of the fortified string functions (strncpy, strcat), don't yet
place a limit on reads from the source based on __builtin_object_size of
the source buffer.
* Extending coverage to more string functions like strlcat.
* It should be possible to optionally use __builtin_object_size(x, 1) for
some functions (C strings) to detect intra-object overflows (like
glibc's _FORTIFY_SOURCE=2), but for now this takes the conservative
approach to avoid likely compatibility issues.
* The compile-time checks should be made available via a separate config
option which can be enabled by default (or always enabled) once enough
time has passed to get the issues it catches fixed.
Kees said:
"This is great to have. While it was out-of-tree code, it would have
blocked at least CVE-2016-3858 from being exploitable (improper size
argument to strlcpy()). I've sent a number of fixes for
out-of-bounds-reads that this detected upstream already"
[arnd@arndb.de: x86: fix fortified memcpy]
Link: http://lkml.kernel.org/r/20170627150047.660360-1-arnd@arndb.de
[keescook@chromium.org: avoid panic() in favor of BUG()]
Link: http://lkml.kernel.org/r/20170626235122.GA25261@beast
[keescook@chromium.org: move from -mm, add ARCH_HAS_FORTIFY_SOURCE, tweak Kconfig help]
Link: http://lkml.kernel.org/r/20170526095404.20439-1-danielmicay@gmail.com
Link: http://lkml.kernel.org/r/1497903987-21002-8-git-send-email-keescook@chromium.org
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-12 21:36:10 +00:00
|
|
|
#if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
|
2021-02-26 01:21:20 +00:00
|
|
|
#include <linux/fortify-string.h>
|
include/linux/string.h: add the option of fortified string.h functions
This adds support for compiling with a rough equivalent to the glibc
_FORTIFY_SOURCE=1 feature, providing compile-time and runtime buffer
overflow checks for string.h functions when the compiler determines the
size of the source or destination buffer at compile-time. Unlike glibc,
it covers buffer reads in addition to writes.
GNU C __builtin_*_chk intrinsics are avoided because they would force a
much more complex implementation. They aren't designed to detect read
overflows and offer no real benefit when using an implementation based
on inline checks. Inline checks don't add up to much code size and
allow full use of the regular string intrinsics while avoiding the need
for a bunch of _chk functions and per-arch assembly to avoid wrapper
overhead.
This detects various overflows at compile-time in various drivers and
some non-x86 core kernel code. There will likely be issues caught in
regular use at runtime too.
Future improvements left out of initial implementation for simplicity,
as it's all quite optional and can be done incrementally:
* Some of the fortified string functions (strncpy, strcat), don't yet
place a limit on reads from the source based on __builtin_object_size of
the source buffer.
* Extending coverage to more string functions like strlcat.
* It should be possible to optionally use __builtin_object_size(x, 1) for
some functions (C strings) to detect intra-object overflows (like
glibc's _FORTIFY_SOURCE=2), but for now this takes the conservative
approach to avoid likely compatibility issues.
* The compile-time checks should be made available via a separate config
option which can be enabled by default (or always enabled) once enough
time has passed to get the issues it catches fixed.
Kees said:
"This is great to have. While it was out-of-tree code, it would have
blocked at least CVE-2016-3858 from being exploitable (improper size
argument to strlcpy()). I've sent a number of fixes for
out-of-bounds-reads that this detected upstream already"
[arnd@arndb.de: x86: fix fortified memcpy]
Link: http://lkml.kernel.org/r/20170627150047.660360-1-arnd@arndb.de
[keescook@chromium.org: avoid panic() in favor of BUG()]
Link: http://lkml.kernel.org/r/20170626235122.GA25261@beast
[keescook@chromium.org: move from -mm, add ARCH_HAS_FORTIFY_SOURCE, tweak Kconfig help]
Link: http://lkml.kernel.org/r/20170526095404.20439-1-danielmicay@gmail.com
Link: http://lkml.kernel.org/r/1497903987-21002-8-git-send-email-keescook@chromium.org
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-12 21:36:10 +00:00
|
|
|
#endif
|
fortify: Provide a memcpy trap door for sharp corners
As we continue to narrow the scope of what the FORTIFY memcpy() will
accept and build alternative APIs that give the compiler appropriate
visibility into more complex memcpy scenarios, there is a need for
"unfortified" memcpy use in rare cases where combinations of compiler
behaviors, source code layout, etc, result in cases where the stricter
memcpy checks need to be bypassed until appropriate solutions can be
developed (i.e. fix compiler bugs, code refactoring, new API, etc). The
intention is for this to be used only if there's no other reasonable
solution, for its use to include a justification that can be used
to assess future solutions, and for it to be temporary.
Example usage included, based on analysis and discussion from:
https://lore.kernel.org/netdev/CANn89iLS_2cshtuXPyNUGDPaic=sJiYfvTb_wNLgWrZRyBxZ_g@mail.gmail.com
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Coco Li <lixiaoyan@google.com>
Cc: Tariq Toukan <tariqt@nvidia.com>
Cc: Saeed Mahameed <saeedm@nvidia.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: netdev@vger.kernel.org
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220511025301.3636666-1-keescook@chromium.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-05-11 02:53:01 +00:00
|
|
|
#ifndef unsafe_memcpy
|
|
|
|
|
#define unsafe_memcpy(dst, src, bytes, justification) \
|
|
|
|
|
memcpy(dst, src, bytes)
|
|
|
|
|
#endif
|
include/linux/string.h: add the option of fortified string.h functions
This adds support for compiling with a rough equivalent to the glibc
_FORTIFY_SOURCE=1 feature, providing compile-time and runtime buffer
overflow checks for string.h functions when the compiler determines the
size of the source or destination buffer at compile-time. Unlike glibc,
it covers buffer reads in addition to writes.
GNU C __builtin_*_chk intrinsics are avoided because they would force a
much more complex implementation. They aren't designed to detect read
overflows and offer no real benefit when using an implementation based
on inline checks. Inline checks don't add up to much code size and
allow full use of the regular string intrinsics while avoiding the need
for a bunch of _chk functions and per-arch assembly to avoid wrapper
overhead.
This detects various overflows at compile-time in various drivers and
some non-x86 core kernel code. There will likely be issues caught in
regular use at runtime too.
Future improvements left out of initial implementation for simplicity,
as it's all quite optional and can be done incrementally:
* Some of the fortified string functions (strncpy, strcat), don't yet
place a limit on reads from the source based on __builtin_object_size of
the source buffer.
* Extending coverage to more string functions like strlcat.
* It should be possible to optionally use __builtin_object_size(x, 1) for
some functions (C strings) to detect intra-object overflows (like
glibc's _FORTIFY_SOURCE=2), but for now this takes the conservative
approach to avoid likely compatibility issues.
* The compile-time checks should be made available via a separate config
option which can be enabled by default (or always enabled) once enough
time has passed to get the issues it catches fixed.
Kees said:
"This is great to have. While it was out-of-tree code, it would have
blocked at least CVE-2016-3858 from being exploitable (improper size
argument to strlcpy()). I've sent a number of fixes for
out-of-bounds-reads that this detected upstream already"
[arnd@arndb.de: x86: fix fortified memcpy]
Link: http://lkml.kernel.org/r/20170627150047.660360-1-arnd@arndb.de
[keescook@chromium.org: avoid panic() in favor of BUG()]
Link: http://lkml.kernel.org/r/20170626235122.GA25261@beast
[keescook@chromium.org: move from -mm, add ARCH_HAS_FORTIFY_SOURCE, tweak Kconfig help]
Link: http://lkml.kernel.org/r/20170526095404.20439-1-danielmicay@gmail.com
Link: http://lkml.kernel.org/r/1497903987-21002-8-git-send-email-keescook@chromium.org
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-12 21:36:10 +00:00
|
|
|
|
2021-11-02 14:24:20 +00:00
|
|
|
void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count,
|
|
|
|
|
int pad);
|
2017-08-14 20:12:38 +00:00
|
|
|
|
string: Introduce strtomem() and strtomem_pad()
One of the "legitimate" uses of strncpy() is copying a NUL-terminated
string into a fixed-size non-NUL-terminated character array. To avoid
the weaknesses and ambiguity of intent when using strncpy(), provide
replacement functions that explicitly distinguish between trailing
padding and not, and require the destination buffer size be discoverable
by the compiler.
For example:
struct obj {
int foo;
char small[4] __nonstring;
char big[8] __nonstring;
int bar;
};
struct obj p;
/* This will truncate to 4 chars with no trailing NUL */
strncpy(p.small, "hello", sizeof(p.small));
/* p.small contains 'h', 'e', 'l', 'l' */
/* This will NUL pad to 8 chars. */
strncpy(p.big, "hello", sizeof(p.big));
/* p.big contains 'h', 'e', 'l', 'l', 'o', '\0', '\0', '\0' */
When the "__nonstring" attributes are missing, the intent of the
programmer becomes ambiguous for whether the lack of a trailing NUL
in the p.small copy is a bug. Additionally, it's not clear whether
the trailing padding in the p.big copy is _needed_. Both cases
become unambiguous with:
strtomem(p.small, "hello");
strtomem_pad(p.big, "hello", 0);
See also https://github.com/KSPP/linux/issues/90
Expand the memcpy KUnit tests to include these functions.
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
2022-08-26 18:04:43 +00:00
|
|
|
/**
|
|
|
|
|
* strtomem_pad - Copy NUL-terminated string to non-NUL-terminated buffer
|
|
|
|
|
*
|
|
|
|
|
* @dest: Pointer of destination character array (marked as __nonstring)
|
|
|
|
|
* @src: Pointer to NUL-terminated string
|
|
|
|
|
* @pad: Padding character to fill any remaining bytes of @dest after copy
|
|
|
|
|
*
|
|
|
|
|
* This is a replacement for strncpy() uses where the destination is not
|
|
|
|
|
* a NUL-terminated string, but with bounds checking on the source size, and
|
|
|
|
|
* an explicit padding character. If padding is not required, use strtomem().
|
|
|
|
|
*
|
|
|
|
|
* Note that the size of @dest is not an argument, as the length of @dest
|
|
|
|
|
* must be discoverable by the compiler.
|
|
|
|
|
*/
|
|
|
|
|
#define strtomem_pad(dest, src, pad) do { \
|
|
|
|
|
const size_t _dest_len = __builtin_object_size(dest, 1); \
|
string: Adjust strtomem() logic to allow for smaller sources
Arnd noticed we have a case where a shorter source string is being copied
into a destination byte array, but this results in a strnlen() call that
exceeds the size of the source. This is seen with -Wstringop-overread:
In file included from ../include/linux/uuid.h:11,
from ../include/linux/mod_devicetable.h:14,
from ../include/linux/cpufeature.h:12,
from ../arch/x86/coco/tdx/tdx.c:7:
../arch/x86/coco/tdx/tdx.c: In function 'tdx_panic.constprop':
../include/linux/string.h:284:9: error: 'strnlen' specified bound 64 exceeds source size 60 [-Werror=stringop-overread]
284 | memcpy_and_pad(dest, _dest_len, src, strnlen(src, _dest_len), pad); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../arch/x86/coco/tdx/tdx.c:124:9: note: in expansion of macro 'strtomem_pad'
124 | strtomem_pad(message.str, msg, '\0');
| ^~~~~~~~~~~~
Use the smaller of the two buffer sizes when calling strnlen(). When
src length is unknown (SIZE_MAX), it is adjusted to use dest length,
which is what the original code did.
Reported-by: Arnd Bergmann <arnd@arndb.de>
Fixes: dfbafa70bde2 ("string: Introduce strtomem() and strtomem_pad()")
Tested-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andy Shevchenko <andy@kernel.org>
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
2023-10-18 17:53:58 +00:00
|
|
|
const size_t _src_len = __builtin_object_size(src, 1); \
|
string: Introduce strtomem() and strtomem_pad()
One of the "legitimate" uses of strncpy() is copying a NUL-terminated
string into a fixed-size non-NUL-terminated character array. To avoid
the weaknesses and ambiguity of intent when using strncpy(), provide
replacement functions that explicitly distinguish between trailing
padding and not, and require the destination buffer size be discoverable
by the compiler.
For example:
struct obj {
int foo;
char small[4] __nonstring;
char big[8] __nonstring;
int bar;
};
struct obj p;
/* This will truncate to 4 chars with no trailing NUL */
strncpy(p.small, "hello", sizeof(p.small));
/* p.small contains 'h', 'e', 'l', 'l' */
/* This will NUL pad to 8 chars. */
strncpy(p.big, "hello", sizeof(p.big));
/* p.big contains 'h', 'e', 'l', 'l', 'o', '\0', '\0', '\0' */
When the "__nonstring" attributes are missing, the intent of the
programmer becomes ambiguous for whether the lack of a trailing NUL
in the p.small copy is a bug. Additionally, it's not clear whether
the trailing padding in the p.big copy is _needed_. Both cases
become unambiguous with:
strtomem(p.small, "hello");
strtomem_pad(p.big, "hello", 0);
See also https://github.com/KSPP/linux/issues/90
Expand the memcpy KUnit tests to include these functions.
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
2022-08-26 18:04:43 +00:00
|
|
|
\
|
|
|
|
|
BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \
|
|
|
|
|
_dest_len == (size_t)-1); \
|
string: Adjust strtomem() logic to allow for smaller sources
Arnd noticed we have a case where a shorter source string is being copied
into a destination byte array, but this results in a strnlen() call that
exceeds the size of the source. This is seen with -Wstringop-overread:
In file included from ../include/linux/uuid.h:11,
from ../include/linux/mod_devicetable.h:14,
from ../include/linux/cpufeature.h:12,
from ../arch/x86/coco/tdx/tdx.c:7:
../arch/x86/coco/tdx/tdx.c: In function 'tdx_panic.constprop':
../include/linux/string.h:284:9: error: 'strnlen' specified bound 64 exceeds source size 60 [-Werror=stringop-overread]
284 | memcpy_and_pad(dest, _dest_len, src, strnlen(src, _dest_len), pad); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../arch/x86/coco/tdx/tdx.c:124:9: note: in expansion of macro 'strtomem_pad'
124 | strtomem_pad(message.str, msg, '\0');
| ^~~~~~~~~~~~
Use the smaller of the two buffer sizes when calling strnlen(). When
src length is unknown (SIZE_MAX), it is adjusted to use dest length,
which is what the original code did.
Reported-by: Arnd Bergmann <arnd@arndb.de>
Fixes: dfbafa70bde2 ("string: Introduce strtomem() and strtomem_pad()")
Tested-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andy Shevchenko <andy@kernel.org>
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
2023-10-18 17:53:58 +00:00
|
|
|
memcpy_and_pad(dest, _dest_len, src, \
|
|
|
|
|
strnlen(src, min(_src_len, _dest_len)), pad); \
|
string: Introduce strtomem() and strtomem_pad()
One of the "legitimate" uses of strncpy() is copying a NUL-terminated
string into a fixed-size non-NUL-terminated character array. To avoid
the weaknesses and ambiguity of intent when using strncpy(), provide
replacement functions that explicitly distinguish between trailing
padding and not, and require the destination buffer size be discoverable
by the compiler.
For example:
struct obj {
int foo;
char small[4] __nonstring;
char big[8] __nonstring;
int bar;
};
struct obj p;
/* This will truncate to 4 chars with no trailing NUL */
strncpy(p.small, "hello", sizeof(p.small));
/* p.small contains 'h', 'e', 'l', 'l' */
/* This will NUL pad to 8 chars. */
strncpy(p.big, "hello", sizeof(p.big));
/* p.big contains 'h', 'e', 'l', 'l', 'o', '\0', '\0', '\0' */
When the "__nonstring" attributes are missing, the intent of the
programmer becomes ambiguous for whether the lack of a trailing NUL
in the p.small copy is a bug. Additionally, it's not clear whether
the trailing padding in the p.big copy is _needed_. Both cases
become unambiguous with:
strtomem(p.small, "hello");
strtomem_pad(p.big, "hello", 0);
See also https://github.com/KSPP/linux/issues/90
Expand the memcpy KUnit tests to include these functions.
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
2022-08-26 18:04:43 +00:00
|
|
|
} while (0)
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* strtomem - Copy NUL-terminated string to non-NUL-terminated buffer
|
|
|
|
|
*
|
|
|
|
|
* @dest: Pointer of destination character array (marked as __nonstring)
|
|
|
|
|
* @src: Pointer to NUL-terminated string
|
|
|
|
|
*
|
|
|
|
|
* This is a replacement for strncpy() uses where the destination is not
|
|
|
|
|
* a NUL-terminated string, but with bounds checking on the source size, and
|
|
|
|
|
* without trailing padding. If padding is required, use strtomem_pad().
|
|
|
|
|
*
|
|
|
|
|
* Note that the size of @dest is not an argument, as the length of @dest
|
|
|
|
|
* must be discoverable by the compiler.
|
|
|
|
|
*/
|
|
|
|
|
#define strtomem(dest, src) do { \
|
|
|
|
|
const size_t _dest_len = __builtin_object_size(dest, 1); \
|
string: Adjust strtomem() logic to allow for smaller sources
Arnd noticed we have a case where a shorter source string is being copied
into a destination byte array, but this results in a strnlen() call that
exceeds the size of the source. This is seen with -Wstringop-overread:
In file included from ../include/linux/uuid.h:11,
from ../include/linux/mod_devicetable.h:14,
from ../include/linux/cpufeature.h:12,
from ../arch/x86/coco/tdx/tdx.c:7:
../arch/x86/coco/tdx/tdx.c: In function 'tdx_panic.constprop':
../include/linux/string.h:284:9: error: 'strnlen' specified bound 64 exceeds source size 60 [-Werror=stringop-overread]
284 | memcpy_and_pad(dest, _dest_len, src, strnlen(src, _dest_len), pad); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../arch/x86/coco/tdx/tdx.c:124:9: note: in expansion of macro 'strtomem_pad'
124 | strtomem_pad(message.str, msg, '\0');
| ^~~~~~~~~~~~
Use the smaller of the two buffer sizes when calling strnlen(). When
src length is unknown (SIZE_MAX), it is adjusted to use dest length,
which is what the original code did.
Reported-by: Arnd Bergmann <arnd@arndb.de>
Fixes: dfbafa70bde2 ("string: Introduce strtomem() and strtomem_pad()")
Tested-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andy Shevchenko <andy@kernel.org>
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
2023-10-18 17:53:58 +00:00
|
|
|
const size_t _src_len = __builtin_object_size(src, 1); \
|
string: Introduce strtomem() and strtomem_pad()
One of the "legitimate" uses of strncpy() is copying a NUL-terminated
string into a fixed-size non-NUL-terminated character array. To avoid
the weaknesses and ambiguity of intent when using strncpy(), provide
replacement functions that explicitly distinguish between trailing
padding and not, and require the destination buffer size be discoverable
by the compiler.
For example:
struct obj {
int foo;
char small[4] __nonstring;
char big[8] __nonstring;
int bar;
};
struct obj p;
/* This will truncate to 4 chars with no trailing NUL */
strncpy(p.small, "hello", sizeof(p.small));
/* p.small contains 'h', 'e', 'l', 'l' */
/* This will NUL pad to 8 chars. */
strncpy(p.big, "hello", sizeof(p.big));
/* p.big contains 'h', 'e', 'l', 'l', 'o', '\0', '\0', '\0' */
When the "__nonstring" attributes are missing, the intent of the
programmer becomes ambiguous for whether the lack of a trailing NUL
in the p.small copy is a bug. Additionally, it's not clear whether
the trailing padding in the p.big copy is _needed_. Both cases
become unambiguous with:
strtomem(p.small, "hello");
strtomem_pad(p.big, "hello", 0);
See also https://github.com/KSPP/linux/issues/90
Expand the memcpy KUnit tests to include these functions.
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
2022-08-26 18:04:43 +00:00
|
|
|
\
|
|
|
|
|
BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \
|
|
|
|
|
_dest_len == (size_t)-1); \
|
string: Adjust strtomem() logic to allow for smaller sources
Arnd noticed we have a case where a shorter source string is being copied
into a destination byte array, but this results in a strnlen() call that
exceeds the size of the source. This is seen with -Wstringop-overread:
In file included from ../include/linux/uuid.h:11,
from ../include/linux/mod_devicetable.h:14,
from ../include/linux/cpufeature.h:12,
from ../arch/x86/coco/tdx/tdx.c:7:
../arch/x86/coco/tdx/tdx.c: In function 'tdx_panic.constprop':
../include/linux/string.h:284:9: error: 'strnlen' specified bound 64 exceeds source size 60 [-Werror=stringop-overread]
284 | memcpy_and_pad(dest, _dest_len, src, strnlen(src, _dest_len), pad); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../arch/x86/coco/tdx/tdx.c:124:9: note: in expansion of macro 'strtomem_pad'
124 | strtomem_pad(message.str, msg, '\0');
| ^~~~~~~~~~~~
Use the smaller of the two buffer sizes when calling strnlen(). When
src length is unknown (SIZE_MAX), it is adjusted to use dest length,
which is what the original code did.
Reported-by: Arnd Bergmann <arnd@arndb.de>
Fixes: dfbafa70bde2 ("string: Introduce strtomem() and strtomem_pad()")
Tested-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andy Shevchenko <andy@kernel.org>
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
2023-10-18 17:53:58 +00:00
|
|
|
memcpy(dest, src, strnlen(src, min(_src_len, _dest_len))); \
|
string: Introduce strtomem() and strtomem_pad()
One of the "legitimate" uses of strncpy() is copying a NUL-terminated
string into a fixed-size non-NUL-terminated character array. To avoid
the weaknesses and ambiguity of intent when using strncpy(), provide
replacement functions that explicitly distinguish between trailing
padding and not, and require the destination buffer size be discoverable
by the compiler.
For example:
struct obj {
int foo;
char small[4] __nonstring;
char big[8] __nonstring;
int bar;
};
struct obj p;
/* This will truncate to 4 chars with no trailing NUL */
strncpy(p.small, "hello", sizeof(p.small));
/* p.small contains 'h', 'e', 'l', 'l' */
/* This will NUL pad to 8 chars. */
strncpy(p.big, "hello", sizeof(p.big));
/* p.big contains 'h', 'e', 'l', 'l', 'o', '\0', '\0', '\0' */
When the "__nonstring" attributes are missing, the intent of the
programmer becomes ambiguous for whether the lack of a trailing NUL
in the p.small copy is a bug. Additionally, it's not clear whether
the trailing padding in the p.big copy is _needed_. Both cases
become unambiguous with:
strtomem(p.small, "hello");
strtomem_pad(p.big, "hello", 0);
See also https://github.com/KSPP/linux/issues/90
Expand the memcpy KUnit tests to include these functions.
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
2022-08-26 18:04:43 +00:00
|
|
|
} while (0)
|
|
|
|
|
|
2021-05-18 03:16:57 +00:00
|
|
|
/**
|
|
|
|
|
* memset_after - Set a value after a struct member to the end of a struct
|
|
|
|
|
*
|
|
|
|
|
* @obj: Address of target struct instance
|
|
|
|
|
* @v: Byte value to repeatedly write
|
|
|
|
|
* @member: after which struct member to start writing bytes
|
|
|
|
|
*
|
|
|
|
|
* This is good for clearing padding following the given member.
|
|
|
|
|
*/
|
|
|
|
|
#define memset_after(obj, v, member) \
|
|
|
|
|
({ \
|
|
|
|
|
u8 *__ptr = (u8 *)(obj); \
|
|
|
|
|
typeof(v) __val = (v); \
|
|
|
|
|
memset(__ptr + offsetofend(typeof(*(obj)), member), __val, \
|
|
|
|
|
sizeof(*(obj)) - offsetofend(typeof(*(obj)), member)); \
|
|
|
|
|
})
|
|
|
|
|
|
2021-05-18 03:16:57 +00:00
|
|
|
/**
|
|
|
|
|
* memset_startat - Set a value starting at a member to the end of a struct
|
|
|
|
|
*
|
|
|
|
|
* @obj: Address of target struct instance
|
|
|
|
|
* @v: Byte value to repeatedly write
|
|
|
|
|
* @member: struct member to start writing at
|
|
|
|
|
*
|
|
|
|
|
* Note that if there is padding between the prior member and the target
|
|
|
|
|
* member, memset_after() should be used to clear the prior padding.
|
|
|
|
|
*/
|
|
|
|
|
#define memset_startat(obj, v, member) \
|
|
|
|
|
({ \
|
|
|
|
|
u8 *__ptr = (u8 *)(obj); \
|
|
|
|
|
typeof(v) __val = (v); \
|
|
|
|
|
memset(__ptr + offsetof(typeof(*(obj)), member), __val, \
|
|
|
|
|
sizeof(*(obj)) - offsetof(typeof(*(obj)), member)); \
|
|
|
|
|
})
|
|
|
|
|
|
string.h: Add str_has_prefix() helper function
A discussion came up in the trace triggers thread about converting a
bunch of:
strncmp(str, "const", sizeof("const") - 1)
use cases into a helper macro. It started with:
strncmp(str, const, sizeof(const) - 1)
But then Joe Perches mentioned that if a const is not used, the
sizeof() will be the size of a pointer, which can be bad. And that
gcc will optimize strlen("const") into "sizeof("const") - 1".
Thinking about this more, a quick grep in the kernel tree found several
(thousands!) of cases that use this construct. A quick grep also
revealed that there's probably several bugs in that use case. Some are
that people forgot the "- 1" (which I found) and others could be that
the constant for the sizeof is different than the constant (although, I
haven't found any of those, but I also didn't look hard).
I figured the best thing to do is to create a helper macro and place it
into include/linux/string.h. And go around and fix all the open coded
versions of it later.
Note, gcc appears to optimize this when we make it into an always_inline
static function, which removes a lot of issues that a macro produces.
Link: http://lkml.kernel.org/r/e3e754f2bd18e56eaa8baf79bee619316ebf4cfc.1545161087.git.tom.zanussi@linux.intel.com
Link: http://lkml.kernel.org/r/20181219211615.2298e781@gandalf.local.home
Link: http://lkml.kernel.org/r/CAHk-=wg_sR-UEC1ggmkZpypOUYanL5CMX4R7ceuaV4QMf5jBtg@mail.gmail.com
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Suggestions-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggestions-by: Joe Perches <joe@perches.com>
Suggestions-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-12-21 23:10:14 +00:00
|
|
|
/**
|
|
|
|
|
* str_has_prefix - Test if a string has a given prefix
|
|
|
|
|
* @str: The string to test
|
|
|
|
|
* @prefix: The string to see if @str starts with
|
|
|
|
|
*
|
|
|
|
|
* A common way to test a prefix of a string is to do:
|
|
|
|
|
* strncmp(str, prefix, sizeof(prefix) - 1)
|
|
|
|
|
*
|
|
|
|
|
* But this can lead to bugs due to typos, or if prefix is a pointer
|
|
|
|
|
* and not a constant. Instead use str_has_prefix().
|
|
|
|
|
*
|
2019-09-25 23:46:13 +00:00
|
|
|
* Returns:
|
|
|
|
|
* * strlen(@prefix) if @str starts with @prefix
|
|
|
|
|
* * 0 if @str does not start with @prefix
|
string.h: Add str_has_prefix() helper function
A discussion came up in the trace triggers thread about converting a
bunch of:
strncmp(str, "const", sizeof("const") - 1)
use cases into a helper macro. It started with:
strncmp(str, const, sizeof(const) - 1)
But then Joe Perches mentioned that if a const is not used, the
sizeof() will be the size of a pointer, which can be bad. And that
gcc will optimize strlen("const") into "sizeof("const") - 1".
Thinking about this more, a quick grep in the kernel tree found several
(thousands!) of cases that use this construct. A quick grep also
revealed that there's probably several bugs in that use case. Some are
that people forgot the "- 1" (which I found) and others could be that
the constant for the sizeof is different than the constant (although, I
haven't found any of those, but I also didn't look hard).
I figured the best thing to do is to create a helper macro and place it
into include/linux/string.h. And go around and fix all the open coded
versions of it later.
Note, gcc appears to optimize this when we make it into an always_inline
static function, which removes a lot of issues that a macro produces.
Link: http://lkml.kernel.org/r/e3e754f2bd18e56eaa8baf79bee619316ebf4cfc.1545161087.git.tom.zanussi@linux.intel.com
Link: http://lkml.kernel.org/r/20181219211615.2298e781@gandalf.local.home
Link: http://lkml.kernel.org/r/CAHk-=wg_sR-UEC1ggmkZpypOUYanL5CMX4R7ceuaV4QMf5jBtg@mail.gmail.com
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Suggestions-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggestions-by: Joe Perches <joe@perches.com>
Suggestions-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-12-21 23:10:14 +00:00
|
|
|
*/
|
|
|
|
|
static __always_inline size_t str_has_prefix(const char *str, const char *prefix)
|
|
|
|
|
{
|
|
|
|
|
size_t len = strlen(prefix);
|
|
|
|
|
return strncmp(str, prefix, len) == 0 ? len : 0;
|
|
|
|
|
}
|
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
#endif /* _LINUX_STRING_H_ */
|