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| author | Miklos Szeredi <mszeredi@redhat.com> | 2021-08-04 13:22:58 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-09-22 12:28:00 +0200 |
| commit | b7d4f310bb8f605cff7c4c70014a9e2b866625c4 (patch) | |
| tree | 527a68dd27a3edd7badc61ea83dd7306132e130f | |
| parent | 03cc3a2923d62f847d148f545c711f73f79617f0 (diff) | |
| download | linux-stable-b7d4f310bb8f605cff7c4c70014a9e2b866625c4.tar.gz linux-stable-b7d4f310bb8f605cff7c4c70014a9e2b866625c4.tar.bz2 linux-stable-b7d4f310bb8f605cff7c4c70014a9e2b866625c4.zip | |
fuse: fix use after free in fuse_read_interrupt()
[ Upstream commit e1e71c168813564be0f6ea3d6740a059ca42d177 ]
There is a potential race between fuse_read_interrupt() and
fuse_request_end().
TASK1
in fuse_read_interrupt(): delete req->intr_entry (while holding
fiq->lock)
TASK2
in fuse_request_end(): req->intr_entry is empty -> skip fiq->lock
wake up TASK3
TASK3
request is freed
TASK1
in fuse_read_interrupt(): dereference req->in.h.unique ***BAM***
Fix by always grabbing fiq->lock if the request was ever interrupted
(FR_INTERRUPTED set) thereby serializing with concurrent
fuse_read_interrupt() calls.
FR_INTERRUPTED is set before the request is queued on fiq->interrupts.
Dequeing the request is done with list_del_init() but FR_INTERRUPTED is not
cleared in this case.
Reported-by: lijiazi <lijiazi@xiaomi.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | fs/fuse/dev.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 4140d5c3ab5a..f943eea9fe4e 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -288,10 +288,10 @@ void fuse_request_end(struct fuse_req *req) /* * test_and_set_bit() implies smp_mb() between bit - * changing and below intr_entry check. Pairs with + * changing and below FR_INTERRUPTED check. Pairs with * smp_mb() from queue_interrupt(). */ - if (!list_empty(&req->intr_entry)) { + if (test_bit(FR_INTERRUPTED, &req->flags)) { spin_lock(&fiq->lock); list_del_init(&req->intr_entry); spin_unlock(&fiq->lock); |