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52a9dab6d8
GCC 12 correctly reports a potential use-after-free condition in the
xrealloc helper. Fix the warning by avoiding an implicit "free(ptr)"
when size == 0:
In file included from help.c:12:
In function 'xrealloc',
inlined from 'add_cmdname' at help.c:24:2: subcmd-util.h:56:23: error: pointer may be used after 'realloc' [-Werror=use-after-free]
56 | ret = realloc(ptr, size);
| ^~~~~~~~~~~~~~~~~~
subcmd-util.h:52:21: note: call to 'realloc' here
52 | void *ret = realloc(ptr, size);
| ^~~~~~~~~~~~~~~~~~
subcmd-util.h:58:31: error: pointer may be used after 'realloc' [-Werror=use-after-free]
58 | ret = realloc(ptr, 1);
| ^~~~~~~~~~~~~~~
subcmd-util.h:52:21: note: call to 'realloc' here
52 | void *ret = realloc(ptr, size);
| ^~~~~~~~~~~~~~~~~~
Fixes: 2f4ce5ec1d ("perf tools: Finalize subcmd independence")
Reported-by: Valdis Klētnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Kees Kook <keescook@chromium.org>
Tested-by: Valdis Klētnieks <valdis.kletnieks@vt.edu>
Tested-by: Justin M. Forbes <jforbes@fedoraproject.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-hardening@vger.kernel.org
Cc: Valdis Klētnieks <valdis.kletnieks@vt.edu>
Link: http://lore.kernel.org/lkml/20220213182443.4037039-1-keescook@chromium.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
76 lines
1.7 KiB
C
76 lines
1.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __SUBCMD_UTIL_H
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#define __SUBCMD_UTIL_H
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#include <stdarg.h>
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#include <stdlib.h>
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#include <stdio.h>
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#define NORETURN __attribute__((__noreturn__))
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static inline void report(const char *prefix, const char *err, va_list params)
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{
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char msg[1024];
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vsnprintf(msg, sizeof(msg), err, params);
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fprintf(stderr, " %s%s\n", prefix, msg);
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}
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static NORETURN inline void die(const char *err, ...)
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{
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va_list params;
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va_start(params, err);
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report(" Fatal: ", err, params);
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exit(128);
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va_end(params);
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}
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#define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
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#define alloc_nr(x) (((x)+16)*3/2)
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/*
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* Realloc the buffer pointed at by variable 'x' so that it can hold
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* at least 'nr' entries; the number of entries currently allocated
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* is 'alloc', using the standard growing factor alloc_nr() macro.
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*
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* DO NOT USE any expression with side-effect for 'x' or 'alloc'.
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*/
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#define ALLOC_GROW(x, nr, alloc) \
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do { \
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if ((nr) > alloc) { \
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if (alloc_nr(alloc) < (nr)) \
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alloc = (nr); \
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else \
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alloc = alloc_nr(alloc); \
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x = xrealloc((x), alloc * sizeof(*(x))); \
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} \
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} while(0)
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static inline void *xrealloc(void *ptr, size_t size)
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{
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void *ret = realloc(ptr, size);
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if (!ret)
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die("Out of memory, realloc failed");
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return ret;
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}
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#define astrcatf(out, fmt, ...) \
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({ \
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char *tmp = *(out); \
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if (asprintf((out), "%s" fmt, tmp ?: "", ## __VA_ARGS__) == -1) \
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die("asprintf failed"); \
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free(tmp); \
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})
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static inline void astrcat(char **out, const char *add)
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{
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char *tmp = *out;
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if (asprintf(out, "%s%s", tmp ?: "", add) == -1)
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die("asprintf failed");
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free(tmp);
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}
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#endif /* __SUBCMD_UTIL_H */
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