From: Kees Cook <keescook@chromium.org> stable inclusion from stable-v5.10.102 commit 50f3b00d4c7ba9aef6e0be4db192ee81f4f8a125 bugzilla: https://gitee.com/openeuler/kernel/issues/I567K6 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- 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@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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yu Liao <liaoyu15@huawei.com> Reviewed-by: Wei Li <liwei391@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- tools/lib/subcmd/subcmd-util.h | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) diff --git a/tools/lib/subcmd/subcmd-util.h b/tools/lib/subcmd/subcmd-util.h index 794a375dad36..b2aec04fce8f 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; } -- 2.20.1