From a33d0bfa8e1fc7fef6d7e5c14df2bffd375db424 Mon Sep 17 00:00:00 2001 From: Pratham Patel Date: Sun, 27 Jul 2025 19:18:55 +0530 Subject: [PATCH] ceph: avoid putting the realm twice when decoding snaps fails jira VULN-65927 cve CVE-2022-49770 commit-author Xiubo Li commit 51884d153f7ec85e18d607b2467820a90e0f4359 upstream-diff Absence of the following commit caused a merge conflict: 2e586641c950 ("ceph: do not update snapshot context when there is no new snapshot") When decoding the snaps fails it maybe leaving the 'first_realm' and 'realm' pointing to the same snaprealm memory. And then it'll put it twice and could cause random use-after-free, BUG_ON, etc issues. Cc: stable@vger.kernel.org Link: https://tracker.ceph.com/issues/57686 Signed-off-by: Xiubo Li Reviewed-by: Ilya Dryomov Signed-off-by: Ilya Dryomov (cherry picked from commit 51884d153f7ec85e18d607b2467820a90e0f4359) Signed-off-by: Pratham Patel --- fs/ceph/snap.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c index 3360a131490f5..1354bc1d7f3a3 100644 --- a/fs/ceph/snap.c +++ b/fs/ceph/snap.c @@ -665,7 +665,7 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc, struct ceph_mds_snap_realm *ri; /* encoded */ __le64 *snaps; /* encoded */ __le64 *prior_parent_snaps; /* encoded */ - struct ceph_snap_realm *realm = NULL; + struct ceph_snap_realm *realm; struct ceph_snap_realm *first_realm = NULL; int invalidate = 0; int err = -ENOMEM; @@ -673,6 +673,7 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc, dout("update_snap_trace deletion=%d\n", deletion); more: + realm = NULL; ceph_decode_need(&p, e, sizeof(*ri), bad); ri = p; p += sizeof(*ri);