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authorKirill Tkhai <ktkhai@virtuozzo.com>2018-09-25 12:52:42 +0300
committerMiklos Szeredi <mszeredi@redhat.com>2018-09-28 16:43:21 +0200
commitd2d2d4fb1f54eff0f3faa9762d84f6446a4bc5d0 (patch)
treeddd35a1d08bab57bcd1b35e24f304958b17609f9 /fs/fuse
parentbc78abbd55dd28e2287ec6d6502b842321a17c87 (diff)
fuse: Fix use-after-free in fuse_dev_do_write()
After we found req in request_find() and released the lock, everything may happen with the req in parallel: cpu0 cpu1 fuse_dev_do_write() fuse_dev_do_write() req = request_find(fpq, ...) ... spin_unlock(&fpq->lock) ... ... req = request_find(fpq, oh.unique) ... spin_unlock(&fpq->lock) queue_interrupt(&fc->iq, req); ... ... ... ... ... request_end(fc, req); fuse_put_request(fc, req); ... queue_interrupt(&fc->iq, req); Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 46c34a348b0a ("fuse: no fc->lock for pqueue parts") Cc: <stable@vger.kernel.org> # v4.2
Diffstat (limited to 'fs/fuse')
-rw-r--r--fs/fuse/dev.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 675caed3e655..c2af8042f176 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1877,16 +1877,20 @@ static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
/* Is it an interrupt reply? */
if (req->intr_unique == oh.unique) {
+ __fuse_get_request(req);
spin_unlock(&fpq->lock);
err = -EINVAL;
- if (nbytes != sizeof(struct fuse_out_header))
+ if (nbytes != sizeof(struct fuse_out_header)) {
+ fuse_put_request(fc, req);
goto err_finish;
+ }
if (oh.error == -ENOSYS)
fc->no_interrupt = 1;
else if (oh.error == -EAGAIN)
queue_interrupt(&fc->iq, req);
+ fuse_put_request(fc, req);
fuse_copy_finish(cs);
return nbytes;