diff options
| -rw-r--r-- | fs/cifs/cifsglob.h | 1 | ||||
| -rw-r--r-- | fs/cifs/smb2pdu.c | 102 | ||||
| -rw-r--r-- | fs/cifs/smb2pdu.h | 3 |
3 files changed, 106 insertions, 0 deletions
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index 2282562e78a1..56fee0330afc 100644 --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -676,6 +676,7 @@ struct TCP_Server_Info { unsigned int max_read; unsigned int max_write; #ifdef CONFIG_CIFS_SMB311 + __le16 cipher_type; /* save initital negprot hash */ __u8 preauth_sha_hash[SMB2_PREAUTH_HASH_SIZE]; #endif /* 3.1.1 */ diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 6c2910e6c984..e01be06d588e 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -406,6 +406,99 @@ assemble_neg_contexts(struct smb2_negotiate_req *req, *total_len += 4 + sizeof(struct smb2_preauth_neg_context) + sizeof(struct smb2_encryption_neg_context); } + +static void decode_preauth_context(struct smb2_preauth_neg_context *ctxt) +{ + unsigned int len = le16_to_cpu(ctxt->DataLength); + + /* If invalid preauth context warn but use what we requested, SHA-512 */ + if (len < MIN_PREAUTH_CTXT_DATA_LEN) { + printk_once(KERN_WARNING "server sent bad preauth context\n"); + return; + } + if (le16_to_cpu(ctxt->HashAlgorithmCount) != 1) + printk_once(KERN_WARNING "illegal SMB3 hash algorithm count\n"); + if (ctxt->HashAlgorithms != SMB2_PREAUTH_INTEGRITY_SHA512) + printk_once(KERN_WARNING "unknown SMB3 hash algorithm\n"); +} + +static int decode_encrypt_ctx(struct TCP_Server_Info *server, + struct smb2_encryption_neg_context *ctxt) +{ + unsigned int len = le16_to_cpu(ctxt->DataLength); + + cifs_dbg(FYI, "decode SMB3.11 encryption neg context of len %d\n", len); + if (len < MIN_ENCRYPT_CTXT_DATA_LEN) { + printk_once(KERN_WARNING "server sent bad crypto ctxt len\n"); + return -EINVAL; + } + + if (le16_to_cpu(ctxt->CipherCount) != 1) { + printk_once(KERN_WARNING "illegal SMB3.11 cipher count\n"); + return -EINVAL; + } + cifs_dbg(FYI, "SMB311 cipher type:%d\n", le16_to_cpu(ctxt->Ciphers[0])); + if ((ctxt->Ciphers[0] != SMB2_ENCRYPTION_AES128_CCM) && + (ctxt->Ciphers[0] != SMB2_ENCRYPTION_AES128_GCM)) { + printk_once(KERN_WARNING "invalid SMB3.11 cipher returned\n"); + return -EINVAL; + } + server->cipher_type = ctxt->Ciphers[0]; + return 0; +} + +static int smb311_decode_neg_context(struct smb2_negotiate_rsp *rsp, + struct TCP_Server_Info *server) +{ + struct smb2_neg_context *pctx; + unsigned int offset = le32_to_cpu(rsp->NegotiateContextOffset); + unsigned int ctxt_cnt = le16_to_cpu(rsp->NegotiateContextCount); + unsigned int len_of_smb = be32_to_cpu(rsp->hdr.smb2_buf_length); + unsigned int len_of_ctxts, i; + int rc = 0; + + cifs_dbg(FYI, "decoding %d negotiate contexts\n", ctxt_cnt); + if (len_of_smb <= offset) { + cifs_dbg(VFS, "Invalid response: negotiate context offset\n"); + return -EINVAL; + } + + len_of_ctxts = len_of_smb - offset; + + for (i = 0; i < ctxt_cnt; i++) { + int clen; + /* check that offset is not beyond end of SMB */ + if (len_of_ctxts == 0) + break; + + if (len_of_ctxts < sizeof(struct smb2_neg_context)) + break; + + pctx = (struct smb2_neg_context *)(offset + 4 + (char *)rsp); + clen = le16_to_cpu(pctx->DataLength); + if (clen > len_of_ctxts) + break; + + if (pctx->ContextType == SMB2_PREAUTH_INTEGRITY_CAPABILITIES) + decode_preauth_context( + (struct smb2_preauth_neg_context *)pctx); + else if (pctx->ContextType == SMB2_ENCRYPTION_CAPABILITIES) + rc = decode_encrypt_ctx(server, + (struct smb2_encryption_neg_context *)pctx); + else + cifs_dbg(VFS, "unknown negcontext of type %d ignored\n", + le16_to_cpu(pctx->ContextType)); + + if (rc) + break; + /* offsets must be 8 byte aligned */ + clen = (clen + 7) & ~0x7; + offset += clen + sizeof(struct smb2_neg_context); + len_of_ctxts -= clen; + } + return rc; +} + #else static void assemble_neg_contexts(struct smb2_negotiate_req *req, unsigned int *total_len) @@ -619,6 +712,15 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses) else if (rc == 0) rc = -EIO; } + +#ifdef CONFIG_CIFS_SMB311 + if (rsp->DialectRevision == cpu_to_le16(SMB311_PROT_ID)) { + if (rsp->NegotiateContextCount) + rc = smb311_decode_neg_context(rsp, server); + else + cifs_dbg(VFS, "Missing expected negotiate contexts\n"); + } +#endif /* CONFIG_CIFS_SMB311 */ neg_exit: free_rsp_buf(resp_buftype, rsp); return rc; diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h index 0e0a0af89e4d..6093e5142b2b 100644 --- a/fs/cifs/smb2pdu.h +++ b/fs/cifs/smb2pdu.h @@ -275,6 +275,7 @@ struct smb2_neg_context { #define SMB2_PREAUTH_INTEGRITY_SHA512 cpu_to_le16(0x0001) #define SMB2_PREAUTH_HASH_SIZE 64 +#define MIN_PREAUTH_CTXT_DATA_LEN (SMB311_SALT_SIZE + 6) struct smb2_preauth_neg_context { __le16 ContextType; /* 1 */ __le16 DataLength; @@ -289,6 +290,8 @@ struct smb2_preauth_neg_context { #define SMB2_ENCRYPTION_AES128_CCM cpu_to_le16(0x0001) #define SMB2_ENCRYPTION_AES128_GCM cpu_to_le16(0x0002) +/* Min encrypt context data is one cipher so 2 bytes + 2 byte count field */ +#define MIN_ENCRYPT_CTXT_DATA_LEN 4 struct smb2_encryption_neg_context { __le16 ContextType; /* 2 */ __le16 DataLength; |