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authorVincent Whitchurch <vincent.whitchurch@axis.com>2021-03-10 15:20:40 +0300
committerSteve French <stfrench@microsoft.com>2021-03-15 02:14:32 +0300
commit05946d4b7a7349ae58bfa2d51ae832e64a394c2d (patch)
treef85ea7afc996d117fb97593feca7df8fe36dbde7
parent5171317dfd9afcf729799d31fffdbb9e71e45402 (diff)
downloadlinux-05946d4b7a7349ae58bfa2d51ae832e64a394c2d.tar.xz
cifs: Fix preauth hash corruption
smb311_update_preauth_hash() uses the shash in server->secmech without appropriate locking, and this can lead to sessions corrupting each other's preauth hashes. The following script can easily trigger the problem: #!/bin/sh -e NMOUNTS=10 for i in $(seq $NMOUNTS); mkdir -p /tmp/mnt$i umount /tmp/mnt$i 2>/dev/null || : done while :; do for i in $(seq $NMOUNTS); do mount -t cifs //192.168.0.1/test /tmp/mnt$i -o ... & done wait for i in $(seq $NMOUNTS); do umount /tmp/mnt$i done done Usually within seconds this leads to one or more of the mounts failing with the following errors, and a "Bad SMB2 signature for message" is seen in the server logs: CIFS: VFS: \\192.168.0.1 failed to connect to IPC (rc=-13) CIFS: VFS: cifs_mount failed w/return code = -13 Fix it by holding the server mutex just like in the other places where the shashes are used. Fixes: 8bd68c6e47abff34e4 ("CIFS: implement v3.11 preauth integrity") Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> CC: <stable@vger.kernel.org> Reviewed-by: Aurelien Aptel <aaptel@suse.com> Signed-off-by: Steve French <stfrench@microsoft.com>
-rw-r--r--fs/cifs/transport.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 007d99437c77..c1725b55f364 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -1196,9 +1196,12 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
/*
* Compounding is never used during session establish.
*/
- if ((ses->status == CifsNew) || (optype & CIFS_NEG_OP) || (optype & CIFS_SESS_OP))
+ if ((ses->status == CifsNew) || (optype & CIFS_NEG_OP) || (optype & CIFS_SESS_OP)) {
+ mutex_lock(&server->srv_mutex);
smb311_update_preauth_hash(ses, rqst[0].rq_iov,
rqst[0].rq_nvec);
+ mutex_unlock(&server->srv_mutex);
+ }
for (i = 0; i < num_rqst; i++) {
rc = wait_for_response(server, midQ[i]);
@@ -1266,7 +1269,9 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
.iov_base = resp_iov[0].iov_base,
.iov_len = resp_iov[0].iov_len
};
+ mutex_lock(&server->srv_mutex);
smb311_update_preauth_hash(ses, &iov, 1);
+ mutex_unlock(&server->srv_mutex);
}
out: