From: Siddhesh Poyarekar Date: Fri, 13 May 2022 04:31:47 +0000 (+0530) Subject: fortify: Ensure that __glibc_fortify condition is a constant [BZ #29141] X-Git-Tag: glibc-2.36~291 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=61a87530108ec9181e1b18a9b727ec3cc3ba7532;p=thirdparty%2Fglibc.git fortify: Ensure that __glibc_fortify condition is a constant [BZ #29141] The fix c8ee1c85 introduced a -1 check for object size without also checking that object size is a constant. Because of this, the tree optimizer passes in gcc fail to fold away one of the branches in __glibc_fortify and trips on a spurious Wstringop-overflow. The warning itself is incorrect and the branch does go away eventually in DCE in the rtl passes in gcc, but the constant check is a helpful hint to simplify code early, so add it in. Resolves: BZ #29141 Signed-off-by: Siddhesh Poyarekar --- diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h index f1faf8292c4..1c2b044a0d2 100644 --- a/misc/sys/cdefs.h +++ b/misc/sys/cdefs.h @@ -164,7 +164,7 @@ /* Length is known to be safe at compile time if the __L * __S <= __OBJSZ condition can be folded to a constant and if it is true, or unknown (-1) */ #define __glibc_safe_or_unknown_len(__l, __s, __osz) \ - ((__osz) == (__SIZE_TYPE__) -1 \ + ((__builtin_constant_p (__osz) && (__osz) == (__SIZE_TYPE__) -1) \ || (__glibc_unsigned_or_positive (__l) \ && __builtin_constant_p (__glibc_safe_len_cond ((__SIZE_TYPE__) (__l), \ (__s), (__osz))) \