diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2019-04-24 10:19:25 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-31 16:48:17 +0300 |
| commit | 50013eadda59b9bbbc48eee40ecbfccefc875cc6 (patch) | |
| tree | 97b417880c8fc0e2853dc53c910d170107c44b54 /lib/strncpy_from_user.c | |
| parent | f08f10f79267eb5d79aab724dcf6d8f60dcc2f6d (diff) | |
| download | linux-50013eadda59b9bbbc48eee40ecbfccefc875cc6.tar.xz | |
mm/uaccess: Use 'unsigned long' to placate UBSAN warnings on older GCC versions
[ Upstream commit 29da93fea3ea39ab9b12270cc6be1b70ef201c9e ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'lib/strncpy_from_user.c')
| -rw-r--r-- | lib/strncpy_from_user.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c index 7e35fc450c5b..5a07f19059c3 100644 --- a/lib/strncpy_from_user.c +++ b/lib/strncpy_from_user.c @@ -22,10 +22,11 @@ * hit it), 'max' is the address space maximum (and we return * -EFAULT if we hit it). */ -static inline long do_strncpy_from_user(char *dst, const char __user *src, long count, unsigned long max) +static inline long do_strncpy_from_user(char *dst, const char __user *src, + unsigned long count, unsigned long max) { const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS; - long res = 0; + unsigned long res = 0; /* * Truncate 'max' to the user-specified limit, so that |