Merge tag '6.7-rc6-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull smb client fixes from Steve French:

 - two multichannel reconnect fixes, one fixing an important refcounting
   problem that can lead to umount problems

 - atime fix

 - five fixes for various potential OOB accesses, including a CVE fix,
   and two additional fixes for problems pointed out by Robert Morris's
   fuzzing investigation

* tag '6.7-rc6-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: do not let cifs_chan_update_iface deallocate channels
  cifs: fix a pending undercount of srv_count
  fs: cifs: Fix atime update check
  smb: client: fix potential OOB in smb2_dump_detail()
  smb: client: fix potential OOB in cifs_dump_detail()
  smb: client: fix OOB in smbCalcSize()
  smb: client: fix OOB in SMB2_query_info_init()
  smb: client: fix OOB in cifsd when receiving compounded resps

9 files changed, 93 insertions, 72 deletions

diff --git a/fs/smb/client/cifs_debug.c b/fs/smb/client/cifs_debug.c
index 5596c9f30ccb2..60027f5aebe87 100644
--- a/fs/smb/client/cifs_debug.c
+++ b/fs/smb/client/cifs_debug.c
@@ -40,11 +40,13 @@ void cifs_dump_detail(void *buf, struct TCP_Server_Info *server)
 #ifdef CONFIG_CIFS_DEBUG2
 	struct smb_hdr *smb = buf;
 
-	cifs_dbg(VFS, "Cmd: %d Err: 0x%x Flags: 0x%x Flgs2: 0x%x Mid: %d Pid: %d\n",
-		 smb->Command, smb->Status.CifsError,
-		 smb->Flags, smb->Flags2, smb->Mid, smb->Pid);
-	cifs_dbg(VFS, "smb buf %p len %u\n", smb,
-		 server->ops->calc_smb_size(smb));
+	cifs_dbg(VFS, "Cmd: %d Err: 0x%x Flags: 0x%x Flgs2: 0x%x Mid: %d Pid: %d Wct: %d\n",
+		 smb->Command, smb->Status.CifsError, smb->Flags,
+		 smb->Flags2, smb->Mid, smb->Pid, smb->WordCount);
+	if (!server->ops->check_message(buf, server->total_read, server)) {
+		cifs_dbg(VFS, "smb buf %p len %u\n", smb,
+			 server->ops->calc_smb_size(smb));
+	}
 #endif /* CONFIG_CIFS_DEBUG2 */
 }
 
diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h
index 7558167f603c3..55b3ce944022a 100644
--- a/fs/smb/client/cifsglob.h
+++ b/fs/smb/client/cifsglob.h
@@ -532,7 +532,8 @@ struct smb_version_operations {
 				 struct mid_q_entry **, char **, int *);
 	enum securityEnum (*select_sectype)(struct TCP_Server_Info *,
 			    enum securityEnum);
-	int (*next_header)(char *);
+	int (*next_header)(struct TCP_Server_Info *server, char *buf,
+			   unsigned int *noff);
 	/* ioctl passthrough for query_info */
 	int (*ioctl_query_info)(const unsigned int xid,
 				struct cifs_tcon *tcon,
diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
index 9dc6dc2754c2e..dd2a1fb65e717 100644
--- a/fs/smb/client/connect.c
+++ b/fs/smb/client/connect.c
@@ -1201,7 +1201,12 @@ next_pdu:
 		server->total_read += length;
 
 		if (server->ops->next_header) {
-			next_offset = server->ops->next_header(buf);
+			if (server->ops->next_header(server, buf, &next_offset)) {
+				cifs_dbg(VFS, "%s: malformed response (next_offset=%u)\n",
+					 __func__, next_offset);
+				cifs_reconnect(server, true);
+				continue;
+			}
 			if (next_offset)
 				server->pdu_size = next_offset;
 		}
diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
index cf17e3dd703e6..32a8525415d96 100644
--- a/fs/smb/client/file.c
+++ b/fs/smb/client/file.c
@@ -4671,7 +4671,7 @@ static int cifs_readpage_worker(struct file *file, struct page *page,
 	/* we do not want atime to be less than mtime, it broke some apps */
 	atime = inode_set_atime_to_ts(inode, current_time(inode));
 	mtime = inode_get_mtime(inode);
-	if (timespec64_compare(&atime, &mtime))
+	if (timespec64_compare(&atime, &mtime) < 0)
 		inode_set_atime_to_ts(inode, inode_get_mtime(inode));
 
 	if (PAGE_SIZE > rc)
diff --git a/fs/smb/client/misc.c b/fs/smb/client/misc.c
index 35b176457bbed..c2137ea3c2538 100644
--- a/fs/smb/client/misc.c
+++ b/fs/smb/client/misc.c
@@ -363,6 +363,10 @@ checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
 			cifs_dbg(VFS, "Length less than smb header size\n");
 		}
 		return -EIO;
+	} else if (total_read < sizeof(*smb) + 2 * smb->WordCount) {
+		cifs_dbg(VFS, "%s: can't read BCC due to invalid WordCount(%u)\n",
+			 __func__, smb->WordCount);
+		return -EIO;
 	}
 
 	/* otherwise, there is enough to get to the BCC */
diff --git a/fs/smb/client/sess.c b/fs/smb/client/sess.c
index 816e01c5589b4..2d3b332a79a16 100644
--- a/fs/smb/client/sess.c
+++ b/fs/smb/client/sess.c
@@ -439,7 +439,7 @@ cifs_chan_update_iface(struct cifs_ses *ses, struct TCP_Server_Info *server)
 		cifs_dbg(FYI, "unable to find a suitable iface\n");
 	}
 
-	if (!chan_index && !iface) {
+	if (!iface) {
 		cifs_dbg(FYI, "unable to get the interface matching: %pIS\n",
 			 &ss);
 		spin_unlock(&ses->iface_lock);
@@ -447,7 +447,7 @@ cifs_chan_update_iface(struct cifs_ses *ses, struct TCP_Server_Info *server)
 	}
 
 	/* now drop the ref to the current iface */
-	if (old_iface && iface) {
+	if (old_iface) {
 		cifs_dbg(FYI, "replacing iface: %pIS with %pIS\n",
 			 &old_iface->sockaddr,
 			 &iface->sockaddr);
@@ -460,44 +460,32 @@ cifs_chan_update_iface(struct cifs_ses *ses, struct TCP_Server_Info *server)
 
 		kref_put(&old_iface->refcount, release_iface);
 	} else if (old_iface) {
-		cifs_dbg(FYI, "releasing ref to iface: %pIS\n",
+		/* if a new candidate is not found, keep things as is */
+		cifs_dbg(FYI, "could not replace iface: %pIS\n",
 			 &old_iface->sockaddr);
-
-		old_iface->num_channels--;
-		if (old_iface->weight_fulfilled)
-			old_iface->weight_fulfilled--;
-
-		kref_put(&old_iface->refcount, release_iface);
 	} else if (!chan_index) {
 		/* special case: update interface for primary channel */
-		cifs_dbg(FYI, "referencing primary channel iface: %pIS\n",
-			 &iface->sockaddr);
-		iface->num_channels++;
-		iface->weight_fulfilled++;
-	} else {
-		WARN_ON(!iface);
-		cifs_dbg(FYI, "adding new iface: %pIS\n", &iface->sockaddr);
+		if (iface) {
+			cifs_dbg(FYI, "referencing primary channel iface: %pIS\n",
+				 &iface->sockaddr);
+			iface->num_channels++;
+			iface->weight_fulfilled++;
+		}
 	}
 	spin_unlock(&ses->iface_lock);
 
-	spin_lock(&ses->chan_lock);
-	chan_index = cifs_ses_get_chan_index(ses, server);
-	if (chan_index == CIFS_INVAL_CHAN_INDEX) {
+	if (iface) {
+		spin_lock(&ses->chan_lock);
+		chan_index = cifs_ses_get_chan_index(ses, server);
+		if (chan_index == CIFS_INVAL_CHAN_INDEX) {
+			spin_unlock(&ses->chan_lock);
+			return 0;
+		}
+
+		ses->chans[chan_index].iface = iface;
 		spin_unlock(&ses->chan_lock);
-		return 0;
 	}
 
-	ses->chans[chan_index].iface = iface;
-
-	/* No iface is found. if secondary chan, drop connection */
-	if (!iface && SERVER_IS_CHAN(server))
-		ses->chans[chan_index].server = NULL;
-
-	spin_unlock(&ses->chan_lock);
-
-	if (!iface && SERVER_IS_CHAN(server))
-		cifs_put_tcp_session(server, false);
-
 	return rc;
 }
 
diff --git a/fs/smb/client/smb2misc.c b/fs/smb/client/smb2misc.c
index e20b4354e703b..82b84a4941dd2 100644
--- a/fs/smb/client/smb2misc.c
+++ b/fs/smb/client/smb2misc.c
@@ -173,6 +173,21 @@ smb2_check_message(char *buf, unsigned int len, struct TCP_Server_Info *server)
 	}
 
 	mid = le64_to_cpu(shdr->MessageId);
+	if (check_smb2_hdr(shdr, mid))
+		return 1;
+
+	if (shdr->StructureSize != SMB2_HEADER_STRUCTURE_SIZE) {
+		cifs_dbg(VFS, "Invalid structure size %u\n",
+			 le16_to_cpu(shdr->StructureSize));
+		return 1;
+	}
+
+	command = le16_to_cpu(shdr->Command);
+	if (command >= NUMBER_OF_SMB2_COMMANDS) {
+		cifs_dbg(VFS, "Invalid SMB2 command %d\n", command);
+		return 1;
+	}
+
 	if (len < pdu_size) {
 		if ((len >= hdr_size)
 		    && (shdr->Status != 0)) {
@@ -193,21 +208,6 @@ smb2_check_message(char *buf, unsigned int len, struct TCP_Server_Info *server)
 		return 1;
 	}
 
-	if (check_smb2_hdr(shdr, mid))
-		return 1;
-
-	if (shdr->StructureSize != SMB2_HEADER_STRUCTURE_SIZE) {
-		cifs_dbg(VFS, "Invalid structure size %u\n",
-			 le16_to_cpu(shdr->StructureSize));
-		return 1;
-	}
-
-	command = le16_to_cpu(shdr->Command);
-	if (command >= NUMBER_OF_SMB2_COMMANDS) {
-		cifs_dbg(VFS, "Invalid SMB2 command %d\n", command);
-		return 1;
-	}
-
 	if (smb2_rsp_struct_sizes[command] != pdu->StructureSize2) {
 		if (command != SMB2_OPLOCK_BREAK_HE && (shdr->Status == 0 ||
 		    pdu->StructureSize2 != SMB2_ERROR_STRUCTURE_SIZE2_LE)) {
diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index 8f6f0a38b8868..66b310208545b 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -403,8 +403,10 @@ smb2_dump_detail(void *buf, struct TCP_Server_Info *server)
 	cifs_server_dbg(VFS, "Cmd: %d Err: 0x%x Flags: 0x%x Mid: %llu Pid: %d\n",
 		 shdr->Command, shdr->Status, shdr->Flags, shdr->MessageId,
 		 shdr->Id.SyncId.ProcessId);
-	cifs_server_dbg(VFS, "smb buf %p len %u\n", buf,
-		 server->ops->calc_smb_size(buf));
+	if (!server->ops->check_message(buf, server->total_read, server)) {
+		cifs_server_dbg(VFS, "smb buf %p len %u\n", buf,
+				server->ops->calc_smb_size(buf));
+	}
 #endif
 }
 
@@ -5074,17 +5076,22 @@ smb3_handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 				NULL, 0, false);
 }
 
-static int
-smb2_next_header(char *buf)
+static int smb2_next_header(struct TCP_Server_Info *server, char *buf,
+			    unsigned int *noff)
 {
 	struct smb2_hdr *hdr = (struct smb2_hdr *)buf;
 	struct smb2_transform_hdr *t_hdr = (struct smb2_transform_hdr *)buf;
 
-	if (hdr->ProtocolId == SMB2_TRANSFORM_PROTO_NUM)
-		return sizeof(struct smb2_transform_hdr) +
-		  le32_to_cpu(t_hdr->OriginalMessageSize);
-
-	return le32_to_cpu(hdr->NextCommand);
+	if (hdr->ProtocolId == SMB2_TRANSFORM_PROTO_NUM) {
+		*noff = le32_to_cpu(t_hdr->OriginalMessageSize);
+		if (unlikely(check_add_overflow(*noff, sizeof(*t_hdr), noff)))
+			return -EINVAL;
+	} else {
+		*noff = le32_to_cpu(hdr->NextCommand);
+	}
+	if (unlikely(*noff && *noff < MID_HEADER_SIZE(server)))
+		return -EINVAL;
+	return 0;
 }
 
 int cifs_sfu_make_node(unsigned int xid, struct inode *inode,
diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index c571760ad39a1..4f971c1061f0a 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -411,8 +411,7 @@ skip_sess_setup:
 	}
 
 	if (smb2_command != SMB2_INTERNAL_CMD)
-		if (mod_delayed_work(cifsiod_wq, &server->reconnect, 0))
-			cifs_put_tcp_session(server, false);
+		mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
 
 	atomic_inc(&tconInfoReconnectCount);
 out:
@@ -471,10 +470,15 @@ static int __smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon,
 				 void **request_buf, unsigned int *total_len)
 {
 	/* BB eventually switch this to SMB2 specific small buf size */
-	if (smb2_command == SMB2_SET_INFO)
+	switch (smb2_command) {
+	case SMB2_SET_INFO:
+	case SMB2_QUERY_INFO:
 		*request_buf = cifs_buf_get();
-	else
+		break;
+	default:
 		*request_buf = cifs_small_buf_get();
+		break;
+	}
 	if (*request_buf == NULL) {
 		/* BB should we add a retry in here if not a writepage? */
 		return -ENOMEM;
@@ -3587,8 +3591,13 @@ SMB2_query_info_init(struct cifs_tcon *tcon, struct TCP_Server_Info *server,
 	struct smb2_query_info_req *req;
 	struct kvec *iov = rqst->rq_iov;
 	unsigned int total_len;
+	size_t len;
 	int rc;
 
+	if (unlikely(check_add_overflow(input_len, sizeof(*req), &len) ||
+		     len > CIFSMaxBufSize))
+		return -EINVAL;
+
 	rc = smb2_plain_req_init(SMB2_QUERY_INFO, tcon, server,
 				 (void **) &req, &total_len);
 	if (rc)
@@ -3610,7 +3619,7 @@ SMB2_query_info_init(struct cifs_tcon *tcon, struct TCP_Server_Info *server,
 
 	iov[0].iov_base = (char *)req;
 	/* 1 for Buffer */
-	iov[0].iov_len = total_len - 1 + input_len;
+	iov[0].iov_len = len;
 	return 0;
 }
 
@@ -3618,7 +3627,7 @@ void
 SMB2_query_info_free(struct smb_rqst *rqst)
 {
 	if (rqst && rqst->rq_iov)
-		cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */
+		cifs_buf_release(rqst->rq_iov[0].iov_base); /* request */
 }
 
 static int
@@ -5493,6 +5502,11 @@ build_qfs_info_req(struct kvec *iov, struct cifs_tcon *tcon,
 	return 0;
 }
 
+static inline void free_qfs_info_req(struct kvec *iov)
+{
+	cifs_buf_release(iov->iov_base);
+}
+
 int
 SMB311_posix_qfs_info(const unsigned int xid, struct cifs_tcon *tcon,
 	      u64 persistent_fid, u64 volatile_fid, struct kstatfs *fsdata)
@@ -5524,7 +5538,7 @@ SMB311_posix_qfs_info(const unsigned int xid, struct cifs_tcon *tcon,
 
 	rc = cifs_send_recv(xid, ses, server,
 			    &rqst, &resp_buftype, flags, &rsp_iov);
-	cifs_small_buf_release(iov.iov_base);
+	free_qfs_info_req(&iov);
 	if (rc) {
 		cifs_stats_fail_inc(tcon, SMB2_QUERY_INFO_HE);
 		goto posix_qfsinf_exit;
@@ -5575,7 +5589,7 @@ SMB2_QFS_info(const unsigned int xid, struct cifs_tcon *tcon,
 
 	rc = cifs_send_recv(xid, ses, server,
 			    &rqst, &resp_buftype, flags, &rsp_iov);
-	cifs_small_buf_release(iov.iov_base);
+	free_qfs_info_req(&iov);
 	if (rc) {
 		cifs_stats_fail_inc(tcon, SMB2_QUERY_INFO_HE);
 		goto qfsinf_exit;
@@ -5642,7 +5656,7 @@ SMB2_QFS_attr(const unsigned int xid, struct cifs_tcon *tcon,
 
 	rc = cifs_send_recv(xid, ses, server,
 			    &rqst, &resp_buftype, flags, &rsp_iov);
-	cifs_small_buf_release(iov.iov_base);
+	free_qfs_info_req(&iov);
 	if (rc) {
 		cifs_stats_fail_inc(tcon, SMB2_QUERY_INFO_HE);
 		goto qfsattr_exit;