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| author |   Luo Meng <luomeng12@huawei.com> | 2020-10-23 14:20:05 +0800 |
|---|---|---|
| committer |   Jeff Layton <jlayton@kernel.org> | 2020-10-26 07:59:29 -0400 |
| commit | 16238415eb9886328a89fe7a3cb0b88c7335fe16 (patch) | |
| tree | c890e67a79e391ce51d8962b3dffd634ae61569b | |
| parent | Linux 5.10-rc1 (diff) | |
| download | linux-dev-16238415eb9886328a89fe7a3cb0b88c7335fe16.tar.xz linux-dev-16238415eb9886328a89fe7a3cb0b88c7335fe16.zip | |
locks: Fix UBSAN undefined behaviour in flock64_to_posix_lock
When the sum of fl->fl_start and l->l_len overflows,
UBSAN shows the following warning:
UBSAN: Undefined behaviour in fs/locks.c:482:29
signed integer overflow: 2 + 9223372036854775806
cannot be represented in type 'long long int'
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xe4/0x14e lib/dump_stack.c:118
ubsan_epilogue+0xe/0x81 lib/ubsan.c:161
handle_overflow+0x193/0x1e2 lib/ubsan.c:192
flock64_to_posix_lock fs/locks.c:482 [inline]
flock_to_posix_lock+0x595/0x690 fs/locks.c:515
fcntl_setlk+0xf3/0xa90 fs/locks.c:2262
do_fcntl+0x456/0xf60 fs/fcntl.c:387
__do_sys_fcntl fs/fcntl.c:483 [inline]
__se_sys_fcntl fs/fcntl.c:468 [inline]
__x64_sys_fcntl+0x12d/0x180 fs/fcntl.c:468
do_syscall_64+0xc8/0x5a0 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Fix it by parenthesizing 'l->l_len - 1'.
Signed-off-by: Luo Meng <luomeng12@huawei.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
| -rw-r--r-- | fs/locks.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/locks.c b/fs/locks.c index 1f84a03601fe..bc08610bae2f 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -542,7 +542,7 @@ static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl, if (l->l_len > 0) { if (l->l_len - 1 > OFFSET_MAX - fl->fl_start) return -EOVERFLOW; - fl->fl_end = fl->fl_start + l->l_len - 1; + fl->fl_end = fl->fl_start + (l->l_len - 1); } else if (l->l_len < 0) { if (fl->fl_start + l->l_len < 0) |