From: Pavitra Jha <jhapavitra98@gmail.com> stable inclusion from stable-v6.6.153 commit fa4aa86fff0c56799c2e3f51a88879053285f4a9 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18381 CVE: CVE-2026-80561 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------ commit 437b6551cfcc235eea1d735a874f9d421f555e17 upstream. decode_locker() in cls_lock_client.c contains three unsafe decode operations that allow a malicious or compromised OSD to trigger slab-out-of-bounds reads: 1. ceph_decode_copy() at the locker_id_t name field has no preceding bounds check. With p == end after ceph_start_decoding() accepts struct_len=0, this reads sizeof(ceph_entity_name) = 9 bytes past the validated buffer boundary. 2. *p += sizeof(struct ceph_timespec) after the locker_info_t header is an unchecked pointer advance. A malicious OSD can position p past end, causing all subsequent _safe checks to pass against a bogus boundary. 3. len = ceph_decode_32(p) has no preceding bounds check, and the immediately following *p += len is uncapped. A malicious OSD can send len=0xffffffff, advancing p gigabytes past end and escaping the decode window entirely. Fix all three by replacing bare operations with their safe variants: ceph_decode_copy -> ceph_decode_copy_safe *p += sizeof(...) -> ceph_decode_skip_n ceph_decode_32(p) -> ceph_decode_32_safe *p += len -> ceph_decode_skip_n A new label is added to return -EINVAL on any bounds violation. -EINVAL is appropriate here: the data received from the OSD is structurally malformed, which is an invalid argument to the decode contract regardless of whether the caller or the wire is at fault. Attacker model: a malicious or compromised OSD in a multi-tenant Ceph deployment can trigger this against any kernel client that issues the lock.get_info class method (e.g. during RBD exclusive lock acquisition) without any further privileges beyond OSD session establishment. [ idryomov: use ceph_decode_skip_string() to skip description, trim changelog ] Cc: stable@vger.kernel.org Fixes: d4ed4a530562 ("libceph: support for lock.lock_info") Signed-off-by: Pavitra Jha <jhapavitra98@gmail.com> Reviewed-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Hulk Robot <hulkrobot@huawei.com> Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com> --- net/ceph/cls_lock_client.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/net/ceph/cls_lock_client.c b/net/ceph/cls_lock_client.c index 639793597b76..a9655678be6f 100644 --- a/net/ceph/cls_lock_client.c +++ b/net/ceph/cls_lock_client.c @@ -257,34 +257,39 @@ static int decode_locker(void **p, void *end, struct ceph_locker *locker) ret = ceph_start_decoding(p, end, 1, "locker_id_t", &struct_v, &len); if (ret) return ret; - ceph_decode_copy(p, &locker->id.name, sizeof(locker->id.name)); + ceph_decode_copy_safe(p, end, &locker->id.name, + sizeof(locker->id.name), bad); s = ceph_extract_encoded_string(p, end, NULL, GFP_NOIO); if (IS_ERR(s)) return PTR_ERR(s); locker->id.cookie = s; ret = ceph_start_decoding(p, end, 1, "locker_info_t", &struct_v, &len); if (ret) return ret; - *p += sizeof(struct ceph_timespec); /* skip expiration */ + /* skip expiration */ + ceph_decode_skip_n(p, end, sizeof(struct ceph_timespec), bad); ret = ceph_decode_entity_addr(p, end, &locker->info.addr); if (ret) return ret; - len = ceph_decode_32(p); - *p += len; /* skip description */ + /* skip description */ + ceph_decode_skip_string(p, end, bad); dout("%s %s%llu cookie %s addr %s\n", __func__, ENTITY_NAME(locker->id.name), locker->id.cookie, ceph_pr_addr(&locker->info.addr)); return 0; + +bad: + return -EINVAL; } static int decode_lockers(void **p, void *end, u8 *type, char **tag, struct ceph_locker **lockers, u32 *num_lockers) { -- 2.43.0