From: Kees Cook <keescook@xxxxxxxxxxxx>
tools: Fix use-after-free for realloc(..., 0)
GCC 12 was correctly reporting 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);
| ^~~~~~~~~~~~~~~~~~
Reported-by: "Valdis Klētnieks" <valdis.kletnieks@xxxxxx>
Fixes: 2f4ce5ec1d44 ("perf tools: Finalize subcmd independence")
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
diff --git a/tools/lib/subcmd/subcmd-util.h b/tools/lib/subcmd/subcmd-util.h
index blahblah..blahblah 100644
--- a/tools/lib/subcmd/subcmd-util.h
+++ b/tools/lib/subcmd/subcmd-util.h
@@ -50,15 +50,8 @@ static NORETURN inline void die(const char *err, ...)
static inline void *xrealloc(void *ptr, size_t size)
{
void *ret = realloc(ptr, size);
- if (!ret && !size)
- ret = realloc(ptr, 1);
- if (!ret) {
- ret = realloc(ptr, size);
- if (!ret && !size)
- ret = realloc(ptr, 1);
- if (!ret)
- die("Out of memory, realloc failed");
- }
+ if (!ret)
+ die("Out of memory, realloc failed");
return ret;
}
--
https://gitlab.com/cki-project/kernel-ark/-/merge_requests/1594
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