From: Zihan Xi <zihanx@nebusec.ai> maillist inclusion category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/20387 Reference: https://lore.kernel.org/all/20260930174901.3771743-2-sashal@kernel.org/ -------------------------------- [ Upstream commit 67f4c1c6a1b51e203d986779299824d1c2c590a6 ] smb2_parse_contexts() validates the complete create-context area but does not limit each record to its Next field before dispatching it. A malformed chain can therefore expose bytes beyond the current context to a handler. The QFid handler also used a full response-structure cast although it only reads DiskFileId. The SMB2/SMB3 lease parsers made the same layout assumption: they read LeaseState and LeaseFlags at canonical offsets rather than at DataOffset. A valid non-canonical DataOffset could therefore yield unrelated in-bounds data, while a short DataLength was still accepted. Limit each context to its Next value, reject offsets before the context header, and reject malformed chains. Bound the name range by the current context and do not dispatch a known handler when DataLength is zero. Read the QFid DiskFileId only when the context data covers that field. Parse the lease context from DataOffset and require DataLength to match the v1 or v2 lease_context size used by ksmbd. A size mismatch skips lease parsing without failing the open. Fixes: b8c32dbb0deb ("CIFS: Request SMB2.1 leases") Fixes: f047390a097e ("CIFS: Add create lease v2 context for SMB3") Fixes: 89a5bfa350fa ("smb3: optimize open to not send query file internal info") Cc: stable@vger.kernel.org Reported-by: Vega <vega@nebusec.ai> Assisted-by: LLM Co-developed-by: Luxing Yin <root@tr0jan.top> Signed-off-by: Luxing Yin <root@tr0jan.top> Signed-off-by: Zihan Xi <zihanx@nebusec.ai> Tested-by: Frank Sorenson <sorenson@redhat.com> Signed-off-by: Paulo Alcantara <pc@manguebit.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/cifs/smb2ops.c | 28 ++++++++++++++++++++-------- fs/cifs/smb2pdu.c | 44 ++++++++++++++++++++++++++++++++++---------- 2 files changed, 54 insertions(+), 18 deletions(-) diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index 5f7e25639b41..3db3c32d6d16 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -4165,29 +4165,41 @@ smb3_create_lease_buf(u8 *lease_key, u8 oplock) } static __u8 smb2_parse_lease_buf(void *buf, unsigned int *epoch, char *lease_key) { - struct create_lease *lc = (struct create_lease *)buf; + struct create_context *cc = buf; + struct lease_context lc; *epoch = 0; /* not used */ - if (lc->lcontext.LeaseFlags & SMB2_LEASE_FLAG_BREAK_IN_PROGRESS_LE) + if (le32_to_cpu(cc->DataLength) != sizeof(lc)) + return 0; + + memcpy(&lc, (u8 *)cc + le16_to_cpu(cc->DataOffset), sizeof(lc)); + if (lc.LeaseFlags & SMB2_LEASE_FLAG_BREAK_IN_PROGRESS_LE) return SMB2_OPLOCK_LEVEL_NOCHANGE; - return le32_to_cpu(lc->lcontext.LeaseState); + return le32_to_cpu(lc.LeaseState); } static __u8 smb3_parse_lease_buf(void *buf, unsigned int *epoch, char *lease_key) { - struct create_lease_v2 *lc = (struct create_lease_v2 *)buf; + struct create_context *cc = buf; + struct lease_context_v2 lc; + + if (le32_to_cpu(cc->DataLength) != sizeof(lc)) { + *epoch = 0; + return 0; + } - *epoch = le16_to_cpu(lc->lcontext.Epoch); - if (lc->lcontext.LeaseFlags & SMB2_LEASE_FLAG_BREAK_IN_PROGRESS_LE) + memcpy(&lc, (u8 *)cc + le16_to_cpu(cc->DataOffset), sizeof(lc)); + *epoch = le16_to_cpu(lc.Epoch); + if (lc.LeaseFlags & SMB2_LEASE_FLAG_BREAK_IN_PROGRESS_LE) return SMB2_OPLOCK_LEVEL_NOCHANGE; if (lease_key) - memcpy(lease_key, &lc->lcontext.LeaseKey, SMB2_LEASE_KEY_SIZE); - return le32_to_cpu(lc->lcontext.LeaseState); + memcpy(lease_key, lc.LeaseKey, SMB2_LEASE_KEY_SIZE); + return le32_to_cpu(lc.LeaseState); } static unsigned int smb2_wp_retry_size(struct inode *inode) { diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 29ec57680788..5d9b1b83284e 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -1955,15 +1955,21 @@ create_reconnect_durable_buf(struct cifs_fid *fid) } static void parse_query_id_ctxt(struct create_context *cc, struct smb2_file_all_info *buf) { - struct create_disk_id_rsp *pdisk_id = (struct create_disk_id_rsp *)cc; + u16 doff = le16_to_cpu(cc->DataOffset); + u32 dlen = le32_to_cpu(cc->DataLength); + u8 *beg; - cifs_dbg(FYI, "parse query id context 0x%llx 0x%llx\n", - pdisk_id->DiskFileId, pdisk_id->VolumeId); - buf->IndexNumber = pdisk_id->DiskFileId; + if (dlen < sizeof(__le64)) + return; + + beg = (u8 *)cc + doff; + memcpy(&buf->IndexNumber, beg, sizeof(__le64)); + cifs_dbg(FYI, "parse query id context 0x%llx\n", + le64_to_cpu(buf->IndexNumber)); } static void parse_posix_ctxt(struct create_context *cc, struct smb2_file_all_info *info, struct create_posix_rsp *posix) @@ -2007,10 +2013,11 @@ int smb2_parse_contexts(struct TCP_Server_Info *server, struct create_posix_rsp *posix) { struct smb2_create_rsp *rsp = rsp_iov->iov_base; struct create_context *cc; size_t rem, off, len; + size_t cc_len; size_t doff, dlen; size_t noff, nlen; char *name; static const char smb3_create_tag_posix[] = { 0x93, 0xAD, 0x25, 0x50, 0x9C, @@ -2029,33 +2036,45 @@ int smb2_parse_contexts(struct TCP_Server_Info *server, /* Initialize inode number to 0 in case no valid data in qfid context */ if (buf) buf->IndexNumber = 0; while (rem >= sizeof(*cc)) { + off = le32_to_cpu(cc->Next); + if (off) { + if ((off & 0x7) || off >= rem || off < sizeof(*cc)) + return -EINVAL; + cc_len = off; + } else { + cc_len = rem; + } + doff = le16_to_cpu(cc->DataOffset); dlen = le32_to_cpu(cc->DataLength); - if (check_add_overflow(doff, dlen, &len) || len > rem) + if (doff < sizeof(*cc) || + check_add_overflow(doff, dlen, &len) || len > cc_len) return -EINVAL; noff = le16_to_cpu(cc->NameOffset); nlen = le16_to_cpu(cc->NameLength); - if (noff + nlen > doff) + if (noff < sizeof(*cc) || + check_add_overflow(noff, nlen, &len) || len > cc_len || + (dlen && len > doff)) return -EINVAL; name = (char *)cc + noff; switch (nlen) { case 4: - if (!strncmp(name, SMB2_CREATE_REQUEST_LEASE, 4)) { + if (dlen && !strncmp(name, SMB2_CREATE_REQUEST_LEASE, 4)) { *oplock = server->ops->parse_lease_buf(cc, epoch, lease_key); - } else if (buf && + } else if (dlen && buf && !strncmp(name, SMB2_CREATE_QUERY_ON_DISK_ID, 4)) { parse_query_id_ctxt(cc, buf); } break; case 16: - if (posix && !memcmp(name, smb3_create_tag_posix, 16)) + if (dlen && posix && !memcmp(name, smb3_create_tag_posix, 16)) parse_posix_ctxt(cc, buf, posix); break; default: cifs_dbg(FYI, "%s: unhandled context (nlen=%zu dlen=%zu)\n", __func__, nlen, dlen); @@ -2063,17 +2082,22 @@ int smb2_parse_contexts(struct TCP_Server_Info *server, cifs_dump_mem("context data: ", cc, dlen); break; } off = le32_to_cpu(cc->Next); - if (!off) + if (!off) { + rem = 0; break; + } if (check_sub_overflow(rem, off, &rem)) return -EINVAL; cc = (struct create_context *)((u8 *)cc + off); } + if (rem) + return -EINVAL; + if (rsp->OplockLevel != SMB2_OPLOCK_LEVEL_LEASE) *oplock = rsp->OplockLevel; return 0; } -- 2.52.0