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![Kees Cook](/assets/img/avatar_default.png)
In order to perform future tests against the cred saved during open(), switch kallsyms_show_value() to operate on a cred, and have all current callers pass current_cred(). This makes it very obvious where callers are checking the wrong credential in their "read" contexts. These will be fixed in the coming patches. Additionally switch return value to bool, since it is always used as a direct permission check, not a 0-on-success, negative-on-error style function return. Cc: stable@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
174 lines
4.3 KiB
C
174 lines
4.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* Rewritten and vastly simplified by Rusty Russell for in-kernel
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* module loader:
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* Copyright 2002 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
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*/
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#ifndef _LINUX_KALLSYMS_H
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#define _LINUX_KALLSYMS_H
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/stddef.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <asm/sections.h>
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#define KSYM_NAME_LEN 128
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#define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s]") + (KSYM_NAME_LEN - 1) + \
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2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + 1)
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struct cred;
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struct module;
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static inline int is_kernel_inittext(unsigned long addr)
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{
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if (addr >= (unsigned long)_sinittext
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&& addr <= (unsigned long)_einittext)
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return 1;
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return 0;
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}
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static inline int is_kernel_text(unsigned long addr)
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{
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if ((addr >= (unsigned long)_stext && addr <= (unsigned long)_etext) ||
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arch_is_kernel_text(addr))
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return 1;
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return in_gate_area_no_mm(addr);
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}
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static inline int is_kernel(unsigned long addr)
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{
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if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
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return 1;
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return in_gate_area_no_mm(addr);
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}
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static inline int is_ksym_addr(unsigned long addr)
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{
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if (IS_ENABLED(CONFIG_KALLSYMS_ALL))
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return is_kernel(addr);
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return is_kernel_text(addr) || is_kernel_inittext(addr);
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}
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static inline void *dereference_symbol_descriptor(void *ptr)
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{
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#ifdef HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR
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struct module *mod;
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ptr = dereference_kernel_function_descriptor(ptr);
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if (is_ksym_addr((unsigned long)ptr))
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return ptr;
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preempt_disable();
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mod = __module_address((unsigned long)ptr);
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preempt_enable();
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if (mod)
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ptr = dereference_module_function_descriptor(mod, ptr);
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#endif
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return ptr;
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}
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#ifdef CONFIG_KALLSYMS
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/* Lookup the address for a symbol. Returns 0 if not found. */
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unsigned long kallsyms_lookup_name(const char *name);
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/* Call a function on each kallsyms symbol in the core kernel */
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int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
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unsigned long),
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void *data);
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extern int kallsyms_lookup_size_offset(unsigned long addr,
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unsigned long *symbolsize,
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unsigned long *offset);
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/* Lookup an address. modname is set to NULL if it's in the kernel. */
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const char *kallsyms_lookup(unsigned long addr,
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unsigned long *symbolsize,
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unsigned long *offset,
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char **modname, char *namebuf);
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/* Look up a kernel symbol and return it in a text buffer. */
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extern int sprint_symbol(char *buffer, unsigned long address);
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extern int sprint_symbol_no_offset(char *buffer, unsigned long address);
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extern int sprint_backtrace(char *buffer, unsigned long address);
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int lookup_symbol_name(unsigned long addr, char *symname);
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int lookup_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name);
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/* How and when do we show kallsyms values? */
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extern bool kallsyms_show_value(const struct cred *cred);
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#else /* !CONFIG_KALLSYMS */
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static inline unsigned long kallsyms_lookup_name(const char *name)
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{
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return 0;
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}
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static inline int kallsyms_on_each_symbol(int (*fn)(void *, const char *,
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struct module *,
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unsigned long),
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void *data)
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{
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return 0;
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}
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static inline int kallsyms_lookup_size_offset(unsigned long addr,
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unsigned long *symbolsize,
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unsigned long *offset)
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{
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return 0;
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}
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static inline const char *kallsyms_lookup(unsigned long addr,
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unsigned long *symbolsize,
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unsigned long *offset,
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char **modname, char *namebuf)
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{
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return NULL;
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}
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static inline int sprint_symbol(char *buffer, unsigned long addr)
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{
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*buffer = '\0';
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return 0;
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}
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static inline int sprint_symbol_no_offset(char *buffer, unsigned long addr)
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{
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*buffer = '\0';
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return 0;
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}
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static inline int sprint_backtrace(char *buffer, unsigned long addr)
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{
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*buffer = '\0';
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return 0;
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}
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static inline int lookup_symbol_name(unsigned long addr, char *symname)
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{
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return -ERANGE;
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}
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static inline int lookup_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name)
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{
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return -ERANGE;
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}
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static inline bool kallsyms_show_value(const struct cred *cred)
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{
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return false;
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}
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#endif /*CONFIG_KALLSYMS*/
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static inline void print_ip_sym(const char *loglvl, unsigned long ip)
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{
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printk("%s[<%px>] %pS\n", loglvl, (void *) ip, (void *) ip);
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}
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#endif /*_LINUX_KALLSYMS_H*/
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