diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2019-04-24 09:19:25 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2019-04-24 12:19:45 +0200 |
| commit | 29da93fea3ea39ab9b12270cc6be1b70ef201c9e (patch) | |
| tree | 1d5dd50a2abb3145a22d6a398cafad8f9067de90 /lib/strnlen_user.c | |
| parent | 6ae865615fc43d014da2fd1f1bba7e81ee622d1b (diff) | |
| download | linux-29da93fea3ea39ab9b12270cc6be1b70ef201c9e.tar.bz2 | |
mm/uaccess: Use 'unsigned long' to placate UBSAN warnings on older GCC versions
Randy reported objtool triggered on his (GCC-7.4) build:
lib/strncpy_from_user.o: warning: objtool: strncpy_from_user()+0x315: call to __ubsan_handle_add_overflow() with UACCESS enabled
lib/strnlen_user.o: warning: objtool: strnlen_user()+0x337: call to __ubsan_handle_sub_overflow() with UACCESS enabled
This is due to UBSAN generating signed-overflow-UB warnings where it
should not. Prior to GCC-8 UBSAN ignored -fwrapv (which the kernel
uses through -fno-strict-overflow).
Make the functions use 'unsigned long' throughout.
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: luto@kernel.org
Link: http://lkml.kernel.org/r/20190424072208.754094071@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'lib/strnlen_user.c')
| -rw-r--r-- | lib/strnlen_user.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/lib/strnlen_user.c b/lib/strnlen_user.c index 1c1a1b0e38a5..7f2db3fe311f 100644 --- a/lib/strnlen_user.c +++ b/lib/strnlen_user.c @@ -28,7 +28,7 @@ static inline long do_strnlen_user(const char __user *src, unsigned long count, unsigned long max) { const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS; - long align, res = 0; + unsigned long align, res = 0; unsigned long c; /* @@ -42,7 +42,7 @@ static inline long do_strnlen_user(const char __user *src, unsigned long count, * Do everything aligned. But that means that we * need to also expand the maximum.. */ - align = (sizeof(long) - 1) & (unsigned long)src; + align = (sizeof(unsigned long) - 1) & (unsigned long)src; src -= align; max += align; |