diff options
Diffstat (limited to 'fs/smb/client/smb1encrypt.c')
| -rw-r--r-- | fs/smb/client/smb1encrypt.c | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/fs/smb/client/smb1encrypt.c b/fs/smb/client/smb1encrypt.c new file mode 100644 index 000000000..c9eb68f04 --- /dev/null +++ b/fs/smb/client/smb1encrypt.c @@ -0,0 +1,139 @@ +// SPDX-License-Identifier: LGPL-2.1 +/* + * + * Encryption and hashing operations relating to NTLM, NTLMv2. See MS-NLMP + * for more detailed information + * + * Copyright (C) International Business Machines Corp., 2005,2013 + * Author(s): Steve French (sfrench@us.ibm.com) + * + */ + +#include <linux/fips.h> +#include <crypto/md5.h> +#include <crypto/utils.h> +#include "cifsproto.h" +#include "smb1proto.h" +#include "cifs_debug.h" + +/* + * Calculate and return the CIFS signature based on the mac key and SMB PDU. + * The 16 byte signature must be allocated by the caller. Note we only use the + * 1st eight bytes and that the smb header signature field on input contains + * the sequence number before this function is called. Also, this function + * should be called with the server->srv_mutex held. + */ +static int cifs_calc_signature(struct smb_rqst *rqst, + struct TCP_Server_Info *server, char *signature) +{ + struct md5_ctx ctx; + + if (!rqst->rq_iov || !signature || !server) + return -EINVAL; + if (fips_enabled) { + cifs_dbg(VFS, + "MD5 signature support is disabled due to FIPS\n"); + return -EOPNOTSUPP; + } + + md5_init(&ctx); + md5_update(&ctx, server->session_key.response, server->session_key.len); + + return __cifs_calc_signature( + rqst, server, signature, + &(struct cifs_calc_sig_ctx){ .md5 = &ctx }); +} + +/* must be called with server->srv_mutex held */ +int cifs_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server, + __u32 *pexpected_response_sequence_number) +{ + int rc = 0; + char smb_signature[20]; + struct smb_hdr *cifs_pdu = (struct smb_hdr *)rqst->rq_iov[0].iov_base; + + if ((cifs_pdu == NULL) || (server == NULL)) + return -EINVAL; + + spin_lock(&server->srv_lock); + if (!(cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) || + server->tcpStatus == CifsNeedNegotiate) { + spin_unlock(&server->srv_lock); + return rc; + } + spin_unlock(&server->srv_lock); + + if (!server->session_estab) { + memcpy(cifs_pdu->Signature.SecuritySignature, "BSRSPYL", 8); + return rc; + } + + cifs_pdu->Signature.Sequence.SequenceNumber = + cpu_to_le32(server->sequence_number); + cifs_pdu->Signature.Sequence.Reserved = 0; + + *pexpected_response_sequence_number = ++server->sequence_number; + ++server->sequence_number; + + rc = cifs_calc_signature(rqst, server, smb_signature); + if (rc) + memset(cifs_pdu->Signature.SecuritySignature, 0, 8); + else + memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8); + + memzero_explicit(smb_signature, sizeof(smb_signature)); + return rc; +} + +int cifs_verify_signature(struct smb_rqst *rqst, + struct TCP_Server_Info *server, + __u32 expected_sequence_number) +{ + unsigned int rc; + char server_response_sig[8]; + char what_we_think_sig_should_be[20]; + struct smb_hdr *cifs_pdu = (struct smb_hdr *)rqst->rq_iov[0].iov_base; + + if (cifs_pdu == NULL || server == NULL) + return -EINVAL; + + if (!server->session_estab) + return 0; + + if (cifs_pdu->Command == SMB_COM_LOCKING_ANDX) { + struct smb_com_lock_req *pSMB = + (struct smb_com_lock_req *)cifs_pdu; + if (pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE) + return 0; + } + + /* BB what if signatures are supposed to be on for session but + server does not send one? BB */ + + /* Do not need to verify session setups with signature "BSRSPYL " */ + if (memcmp(cifs_pdu->Signature.SecuritySignature, "BSRSPYL ", 8) == 0) + cifs_dbg(FYI, "dummy signature received for smb command 0x%x\n", + cifs_pdu->Command); + + /* save off the original signature so we can modify the smb and check + its signature against what the server sent */ + memcpy(server_response_sig, cifs_pdu->Signature.SecuritySignature, 8); + + cifs_pdu->Signature.Sequence.SequenceNumber = + cpu_to_le32(expected_sequence_number); + cifs_pdu->Signature.Sequence.Reserved = 0; + + cifs_server_lock(server); + rc = cifs_calc_signature(rqst, server, what_we_think_sig_should_be); + cifs_server_unlock(server); + + if (!rc) { + if (crypto_memneq(server_response_sig, + what_we_think_sig_should_be, 8)) + rc = -EACCES; + } + + memzero_explicit(what_we_think_sig_should_be, + sizeof(what_we_think_sig_should_be)); + return rc; +} |