From: Kees Cook <keescook@xxxxxxxxxxxx>
commit 52a9dab6d892763b2a8334a568bd4e2c1a6fde66 upstream.
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: 2f4ce5ec1d447beb ("perf tools: Finalize subcmd independence")
Reported-by: Valdis Klētnieks <valdis.kletnieks@xxxxxx>
Signed-off-by: Kees Kook <keescook@xxxxxxxxxxxx>
Tested-by: Valdis Klētnieks <valdis.kletnieks@xxxxxx>
Tested-by: Justin M. Forbes <jforbes@xxxxxxxxxxxxxxxxx>
Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: linux-hardening@xxxxxxxxxxxxxxx
Cc: Valdis Klētnieks <valdis.kletnieks@xxxxxx>
Link: http://lore.kernel.org/lkml/20220213182443.4037039-1-keescook@xxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/lib/subcmd/subcmd-util.h | 11 ++---------
1 file changed, 2 insertions(+), 9 deletions(-)
--- a/tools/lib/subcmd/subcmd-util.h
+++ b/tools/lib/subcmd/subcmd-util.h
@@ -50,15 +50,8 @@ static NORETURN inline void die(const ch
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;
}
