[CIFS] cleanup asn handling for ntlmssp

Also removes obsolete distinction between rawntlmssp and ntlmssp (in asn/SPNEGO)
since as jra noted we can always send raw ntlmssp in session setup now.

remove check for experimental runtime flag (/proc/fs/cifs/Experimental) in
ntlmssp path.

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 49 insertions, 6 deletions

diff --git a/fs/cifs/asn1.c b/fs/cifs/asn1.c
index 1b09f1670061..20692fbfdb24 100644
--- a/fs/cifs/asn1.c
+++ b/fs/cifs/asn1.c
@@ -49,6 +49,7 @@
 #define ASN1_OJI        6       /* Object Identifier  */
 #define ASN1_OJD        7       /* Object Description */
 #define ASN1_EXT        8       /* External */
+#define ASN1_ENUM       10      /* Enumerated */
 #define ASN1_SEQ        16      /* Sequence */
 #define ASN1_SET        17      /* Set */
 #define ASN1_NUMSTR     18      /* Numerical String */
@@ -78,10 +79,12 @@
 #define SPNEGO_OID_LEN 7
 #define NTLMSSP_OID_LEN  10
 #define KRB5_OID_LEN  7
+#define KRB5U2U_OID_LEN  8
 #define MSKRB5_OID_LEN  7
 static unsigned long SPNEGO_OID[7] = { 1, 3, 6, 1, 5, 5, 2 };
 static unsigned long NTLMSSP_OID[10] = { 1, 3, 6, 1, 4, 1, 311, 2, 2, 10 };
 static unsigned long KRB5_OID[7] = { 1, 2, 840, 113554, 1, 2, 2 };
+static unsigned long KRB5U2U_OID[8] = { 1, 2, 840, 113554, 1, 2, 2, 3 };
 static unsigned long MSKRB5_OID[7] = { 1, 2, 840, 48018, 1, 2, 2 };
 
 /*
@@ -122,6 +125,28 @@ asn1_octet_decode(struct asn1_ctx *ctx, unsigned char *ch)
         return 1;
 }
 
+#if 0 /* will be needed later by spnego decoding/encoding of ntlmssp */
+static unsigned char
+asn1_enum_decode(struct asn1_ctx *ctx, __le32 *val)
+{
+        unsigned char ch;
+
+        if (ctx->pointer >= ctx->end) {
+                ctx->error = ASN1_ERR_DEC_EMPTY;
+                return 0;
+        }
+
+        ch = *(ctx->pointer)++; /* ch has 0xa, ptr points to lenght octet */
+        if ((ch) == ASN1_ENUM)  /* if ch value is ENUM, 0xa */
+                *val = *(++(ctx->pointer)); /* value has enum value */
+        else
+                return 0;
+
+        ctx->pointer++;
+        return 1;
+}
+#endif
+
 static unsigned char
 asn1_tag_decode(struct asn1_ctx *ctx, unsigned int *tag)
 {
@@ -476,10 +501,9 @@ decode_negTokenInit(unsigned char *security_blob, int length,
         unsigned int cls, con, tag, oidlen, rc;
         bool use_ntlmssp = false;
         bool use_kerberos = false;
+        bool use_kerberosu2u = false;
         bool use_mskerberos = false;
 
-        *secType = NTLM; /* BB eventually make Kerberos or NLTMSSP the default*/
-
         /* cifs_dump_mem(" Received SecBlob ", security_blob, length); */
 
         asn1_open(&ctx, security_blob, length);
@@ -515,6 +539,7 @@ decode_negTokenInit(unsigned char *security_blob, int length,
                 return 0;
         }
 
+        /* SPNEGO */
         if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
                 cFYI(1, ("Error decoding negTokenInit"));
                 return 0;
@@ -526,6 +551,7 @@ decode_negTokenInit(unsigned char *security_blob, int length,
                 return 0;
         }
 
+        /* negTokenInit */
         if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
                 cFYI(1, ("Error decoding negTokenInit"));
                 return 0;
@@ -537,6 +563,7 @@ decode_negTokenInit(unsigned char *security_blob, int length,
                 return 0;
         }
 
+        /* sequence */
         if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
                 cFYI(1, ("Error decoding 2nd part of negTokenInit"));
                 return 0;
@@ -548,6 +575,7 @@ decode_negTokenInit(unsigned char *security_blob, int length,
                 return 0;
         }
 
+        /* sequence of */
         if (asn1_header_decode
             (&ctx, &sequence_end, &cls, &con, &tag) == 0) {
                 cFYI(1, ("Error decoding 2nd part of negTokenInit"));
@@ -560,6 +588,7 @@ decode_negTokenInit(unsigned char *security_blob, int length,
                 return 0;
         }
 
+        /* list of security mechanisms */
         while (!asn1_eoc_decode(&ctx, sequence_end)) {
                 rc = asn1_header_decode(&ctx, &end, &cls, &con, &tag);
                 if (!rc) {
@@ -576,11 +605,15 @@ decode_negTokenInit(unsigned char *security_blob, int length,
 
                                 if (compare_oid(oid, oidlen, MSKRB5_OID,
                                                 MSKRB5_OID_LEN) &&
-                                                !use_kerberos)
+                                                !use_mskerberos)
                                         use_mskerberos = true;
+                                else if (compare_oid(oid, oidlen, KRB5U2U_OID,
+                                                     KRB5U2U_OID_LEN) &&
+                                                     !use_kerberosu2u)
+                                        use_kerberosu2u = true;
                                 else if (compare_oid(oid, oidlen, KRB5_OID,
                                                      KRB5_OID_LEN) &&
-                                                     !use_mskerberos)
+                                                     !use_kerberos)
                                         use_kerberos = true;
                                 else if (compare_oid(oid, oidlen, NTLMSSP_OID,
                                                      NTLMSSP_OID_LEN))
@@ -593,7 +626,12 @@ decode_negTokenInit(unsigned char *security_blob, int length,
                 }
         }
 
+        /* mechlistMIC */
         if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
+                /* Check if we have reached the end of the blob, but with
+                   no mechListMic (e.g. NTLMSSP instead of KRB5) */
+                if (ctx.error == ASN1_ERR_DEC_EMPTY)
+                        goto decode_negtoken_exit;
                 cFYI(1, ("Error decoding last part negTokenInit exit3"));
                 return 0;
         } else if ((cls != ASN1_CTX) || (con != ASN1_CON)) {
@@ -602,6 +640,8 @@ decode_negTokenInit(unsigned char *security_blob, int length,
                          cls, con, tag, end, *end));
                 return 0;
         }
+
+        /* sequence */
         if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
                 cFYI(1, ("Error decoding last part negTokenInit exit5"));
                 return 0;
@@ -611,6 +651,7 @@ decode_negTokenInit(unsigned char *security_blob, int length,
                         cls, con, tag, end, *end));
         }
 
+        /* sequence of */
         if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
                 cFYI(1, ("Error decoding last part negTokenInit exit 7"));
                 return 0;
@@ -619,6 +660,8 @@ decode_negTokenInit(unsigned char *security_blob, int length,
                          cls, con, tag, end, *end));
                 return 0;
         }
+
+        /* general string */
         if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
                 cFYI(1, ("Error decoding last part negTokenInit exit9"));
                 return 0;
@@ -630,13 +673,13 @@ decode_negTokenInit(unsigned char *security_blob, int length,
         }
         cFYI(1, ("Need to call asn1_octets_decode() function for %s",
                  ctx.pointer)); /* is this UTF-8 or ASCII? */
-
+decode_negtoken_exit:
         if (use_kerberos)
                 *secType = Kerberos;
         else if (use_mskerberos)
                 *secType = MSKerberos;
         else if (use_ntlmssp)
-                *secType = NTLMSSP;
+                *secType = RawNTLMSSP;
 
         return 1;
 }