This is a note to let you know that I've just added the patch titled
NFSv4.0: Fix a use-after-free problem in the asynchronous open()
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsv4.0-fix-a-use-after-free-problem-in-the-asynchro.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b138adc952d563dcbcd367b1bbfae5bded9dd928
Author: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Date: Fri Nov 8 12:13:31 2024 -0500
NFSv4.0: Fix a use-after-free problem in the asynchronous open()
[ Upstream commit 2fdb05dc0931250574f0cb0ebeb5ed8e20f4a889 ]
Yang Erkun reports that when two threads are opening files at the same
time, and are forced to abort before a reply is seen, then the call to
nfs_release_seqid() in nfs4_opendata_free() can result in a
use-after-free of the pointer to the defunct rpc task of the other
thread.
The fix is to ensure that if the RPC call is aborted before the call to
nfs_wait_on_sequence() is complete, then we must call nfs_release_seqid()
in nfs4_open_release() before the rpc_task is freed.
Reported-by: Yang Erkun <yangerkun@xxxxxxxxxx>
Fixes: 24ac23ab88df ("NFSv4: Convert open() into an asynchronous RPC call")
Reviewed-by: Yang Erkun <yangerkun@xxxxxxxxxx>
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 299ea2b86df66..4b12e45f57539 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2528,12 +2528,14 @@ static void nfs4_open_release(void *calldata)
struct nfs4_opendata *data = calldata;
struct nfs4_state *state = NULL;
+ /* In case of error, no cleanup! */
+ if (data->rpc_status != 0 || !data->rpc_done) {
+ nfs_release_seqid(data->o_arg.seqid);
+ goto out_free;
+ }
/* If this request hasn't been cancelled, do nothing */
if (!data->cancelled)
goto out_free;
- /* In case of error, no cleanup! */
- if (data->rpc_status != 0 || !data->rpc_done)
- goto out_free;
/* In case we need an open_confirm, no cleanup! */
if (data->o_res.rflags & NFS4_OPEN_RESULT_CONFIRM)
goto out_free;
