[PATCH 1/3] CIFS: Use OID registry facility

[David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

Use the OID registry facility from fs/cifs/asn1.c as that converts known OIDs
into an enum which should speed up comparison.

Signed-off-by: David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---

 fs/cifs/Kconfig              |    1 
 fs/cifs/asn1.c               |  156 ++++++++----------------------------------
 include/linux/oid_registry.h |    6 ++
 3 files changed, 36 insertions(+), 127 deletions(-)

diff --git a/fs/cifs/Kconfig b/fs/cifs/Kconfig
index 2075ddf..0f7a0a7 100644
--- a/fs/cifs/Kconfig
+++ b/fs/cifs/Kconfig
@@ -10,6 +10,7 @@ config CIFS
 	select CRYPTO_ECB
 	select CRYPTO_DES
 	select CRYPTO_SHA256
+	select OID_REGISTRY
 	help
 	  This is the client VFS module for the Common Internet File System
 	  (CIFS) protocol which is the successor to the Server Message Block
diff --git a/fs/cifs/asn1.c b/fs/cifs/asn1.c
index cfd1ce3..3a7b2b6 100644
--- a/fs/cifs/asn1.c
+++ b/fs/cifs/asn1.c
@@ -22,6 +22,7 @@
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
+#include <linux/oid_registry.h>
 #include "cifspdu.h"
 #include "cifsglob.h"
 #include "cifs_debug.h"
@@ -76,17 +77,6 @@
 #define ASN1_ERR_DEC_LENGTH_MISMATCH	4
 #define ASN1_ERR_DEC_BADVALUE		5
 
-#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 };
-
 /*
  * ASN.1 context.
  */
@@ -397,95 +387,10 @@ asn1_octets_decode(struct asn1_ctx *ctx,
 	return 1;
 } */
 
-static unsigned char
-asn1_subid_decode(struct asn1_ctx *ctx, unsigned long *subid)
+static enum OID
+asn1_oid_decode(struct asn1_ctx *ctx, unsigned char *eoc)
 {
-	unsigned char ch;
-
-	*subid = 0;
-
-	do {
-		if (!asn1_octet_decode(ctx, &ch))
-			return 0;
-
-		*subid <<= 7;
-		*subid |= ch & 0x7F;
-	} while ((ch & 0x80) == 0x80);
-	return 1;
-}
-
-static int
-asn1_oid_decode(struct asn1_ctx *ctx,
-		unsigned char *eoc, unsigned long **oid, unsigned int *len)
-{
-	unsigned long subid;
-	unsigned int size;
-	unsigned long *optr;
-
-	size = eoc - ctx->pointer + 1;
-
-	/* first subid actually encodes first two subids */
-	if (size < 2 || size > UINT_MAX/sizeof(unsigned long))
-		return 0;
-
-	*oid = kmalloc(size * sizeof(unsigned long), GFP_ATOMIC);
-	if (*oid == NULL)
-		return 0;
-
-	optr = *oid;
-
-	if (!asn1_subid_decode(ctx, &subid)) {
-		kfree(*oid);
-		*oid = NULL;
-		return 0;
-	}
-
-	if (subid < 40) {
-		optr[0] = 0;
-		optr[1] = subid;
-	} else if (subid < 80) {
-		optr[0] = 1;
-		optr[1] = subid - 40;
-	} else {
-		optr[0] = 2;
-		optr[1] = subid - 80;
-	}
-
-	*len = 2;
-	optr += 2;
-
-	while (ctx->pointer < eoc) {
-		if (++(*len) > size) {
-			ctx->error = ASN1_ERR_DEC_BADVALUE;
-			kfree(*oid);
-			*oid = NULL;
-			return 0;
-		}
-
-		if (!asn1_subid_decode(ctx, optr++)) {
-			kfree(*oid);
-			*oid = NULL;
-			return 0;
-		}
-	}
-	return 1;
-}
-
-static int
-compare_oid(unsigned long *oid1, unsigned int oid1len,
-	    unsigned long *oid2, unsigned int oid2len)
-{
-	unsigned int i;
-
-	if (oid1len != oid2len)
-		return 0;
-	else {
-		for (i = 0; i < oid1len; i++) {
-			if (oid1[i] != oid2[i])
-				return 0;
-		}
-		return 1;
-	}
+	return look_up_OID(ctx->pointer, eoc - ctx->pointer);
 }
 
 	/* BB check for endian conversion issues here */
@@ -497,8 +402,7 @@ decode_negTokenInit(unsigned char *security_blob, int length,
 	struct asn1_ctx ctx;
 	unsigned char *end;
 	unsigned char *sequence_end;
-	unsigned long *oid = NULL;
-	unsigned int cls, con, tag, oidlen, rc;
+	unsigned int cls, con, tag, rc;
 
 	/* cifs_dump_mem(" Received SecBlob ", security_blob, length); */
 
@@ -519,12 +423,8 @@ decode_negTokenInit(unsigned char *security_blob, int length,
 	if (rc) {
 		if ((tag == ASN1_OJI) && (con == ASN1_PRI) &&
 		    (cls == ASN1_UNI)) {
-			rc = asn1_oid_decode(&ctx, end, &oid, &oidlen);
-			if (rc) {
-				rc = compare_oid(oid, oidlen, SPNEGO_OID,
-						 SPNEGO_OID_LEN);
-				kfree(oid);
-			}
+			if (asn1_oid_decode(&ctx, end) != OID_SPNEGO)
+				rc = 0;
 		} else
 			rc = 0;
 	}
@@ -588,26 +488,28 @@ decode_negTokenInit(unsigned char *security_blob, int length,
 			return 0;
 		}
 		if ((tag == ASN1_OJI) && (con == ASN1_PRI)) {
-			if (asn1_oid_decode(&ctx, end, &oid, &oidlen)) {
-
-				cFYI(1, "OID len = %d oid = 0x%lx 0x%lx "
-					"0x%lx 0x%lx", oidlen, *oid,
-					*(oid + 1), *(oid + 2), *(oid + 3));
-
-				if (compare_oid(oid, oidlen, MSKRB5_OID,
-						MSKRB5_OID_LEN))
-					server->sec_mskerberos = true;
-				else if (compare_oid(oid, oidlen, KRB5U2U_OID,
-						     KRB5U2U_OID_LEN))
-					server->sec_kerberosu2u = true;
-				else if (compare_oid(oid, oidlen, KRB5_OID,
-						     KRB5_OID_LEN))
-					server->sec_kerberos = true;
-				else if (compare_oid(oid, oidlen, NTLMSSP_OID,
-						     NTLMSSP_OID_LEN))
-					server->sec_ntlmssp = true;
-
-				kfree(oid);
+			enum OID oid = asn1_oid_decode(&ctx, end);
+			if (oid != OID__NR)
+				cFYI(1, "OID oid = %u", oid);
+			switch (oid) {
+			case OID_MSKRB5:
+				server->sec_mskerberos = true;
+				break;
+			case OID_KRB5U2U:
+				server->sec_kerberosu2u = true;
+				break;
+			case OID_KRB5:
+				server->sec_kerberos = true;
+				break;
+			case OID_NTLMSSP:
+				server->sec_ntlmssp = true;
+				break;
+			case OID__NR:
+				cFYI(1, "OID len = %ld oid = %*pX",
+				     end - ctx.pointer,
+				     (int)(end - ctx.pointer), ctx.pointer);
+			default:
+				break;
 			}
 		} else {
 			cFYI(1, "Should be an oid what is going on?");
diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h
index 6926db7..4bff9c5 100644
--- a/include/linux/oid_registry.h
+++ b/include/linux/oid_registry.h
@@ -82,6 +82,12 @@ enum OID {
 	OID_authorityKeyIdentifier,	/* 2.5.29.35 */
 	OID_extKeyUsage,		/* 2.5.29.37 */
 
+	OID_SPNEGO,			/* 1.3.6.1.5.5.2 */
+	OID_NTLMSSP,			/* 1.3.6.1.4.1.311.2.2.10 */
+	OID_KRB5,			/* 1.2.840.113554.1.2.2 */
+	OID_KRB5U2U,			/* 1.2.840.113554.1.2.2.3 */
+	OID_MSKRB5,			/* 1.2.840.48018.1.2.2 */
+
 	OID__NR
 };