| Message ID | 20220620175929.736651-1-siddhesh@sourceware.org |
|---|---|
| State | New |
| Headers | show |
| Series | [committed,2.34] fortify: Ensure that __glibc_fortify condition is a constant [BZ #29141] | expand |
diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h index b36013b9a6..e0ecd9147e 100644 --- a/misc/sys/cdefs.h +++ b/misc/sys/cdefs.h @@ -163,7 +163,7 @@ /* 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))) \
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 <siddhesh@sourceware.org> (cherry picked from commit 61a87530108ec9181e1b18a9b727ec3cc3ba7532) --- misc/sys/cdefs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)