Validate SMB message with ->check_message() before calling ->calc_smb_size(). This fixes CVE-2023-6610. Reported-by: j51569436@xxxxxxxxx Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218219 Signed-off-by: Paulo Alcantara <pc@xxxxxxxxxxxxx> --- Steve, I tried to make as little changes as possible for v1 to make backporting easier, but unfortunately we still need to handle "@len < @pdu_size" case in smb2_check_message() otherwise we could call smb2_calc_size() with an invalid command, too. fs/smb/client/smb2misc.c | 30 +++++++++++++++--------------- fs/smb/client/smb2ops.c | 6 ++++-- 2 files changed, 19 insertions(+), 17 deletions(-) diff --git a/fs/smb/client/smb2misc.c b/fs/smb/client/smb2misc.c index e20b4354e703..82b84a4941dd 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 62b0a8df867b..66b310208545 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 } -- 2.43.0
