1 files changed, 39 insertions, 28 deletions

diff --git a/lib/asn1_decoder.c b/lib/asn1_decoder.c
index 0bd8a611eb83..5738ae286b41 100644
--- a/lib/asn1_decoder.c
+++ b/lib/asn1_decoder.c
@@ -1,12 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /* Decoder for ASN.1 BER/DER/CER encoded bytestream
  *
  * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
  */
 
 #include <linux/export.h>
@@ -228,7 +224,7 @@ next_op:
 		hdr = 2;
 
 		/* Extract a tag from the data */
-		if (unlikely(dp >= datalen - 1))
+		if (unlikely(datalen - dp < 2))
 			goto data_overrun_error;
 		tag = data[dp++];
 		if (unlikely((tag & 0x1f) == ASN1_LONG_TAG))
@@ -274,7 +270,7 @@ next_op:
 				int n = len - 0x80;
 				if (unlikely(n > 2))
 					goto length_too_long;
-				if (unlikely(dp >= datalen - n))
+				if (unlikely(n > datalen - dp))
 					goto data_overrun_error;
 				hdr += n;
 				for (len = 0; n > 0; n--) {
@@ -284,6 +280,9 @@ next_op:
 				if (unlikely(len > datalen - dp))
 					goto data_overrun_error;
 			}
+		} else {
+			if (unlikely(len > datalen - dp))
+				goto data_overrun_error;
 		}
 
 		if (flags & FLAG_CONS) {
@@ -310,42 +309,47 @@ next_op:
 
 	/* Decide how to handle the operation */
 	switch (op) {
-	case ASN1_OP_MATCH_ANY_ACT:
-	case ASN1_OP_MATCH_ANY_ACT_OR_SKIP:
-	case ASN1_OP_COND_MATCH_ANY_ACT:
-	case ASN1_OP_COND_MATCH_ANY_ACT_OR_SKIP:
-		ret = actions[machine[pc + 1]](context, hdr, tag, data + dp, len);
-		if (ret < 0)
-			return ret;
-		goto skip_data;
-
-	case ASN1_OP_MATCH_ACT:
-	case ASN1_OP_MATCH_ACT_OR_SKIP:
-	case ASN1_OP_COND_MATCH_ACT_OR_SKIP:
-		ret = actions[machine[pc + 2]](context, hdr, tag, data + dp, len);
-		if (ret < 0)
-			return ret;
-		goto skip_data;
-
 	case ASN1_OP_MATCH:
 	case ASN1_OP_MATCH_OR_SKIP:
+	case ASN1_OP_MATCH_ACT:
+	case ASN1_OP_MATCH_ACT_OR_SKIP:
 	case ASN1_OP_MATCH_ANY:
 	case ASN1_OP_MATCH_ANY_OR_SKIP:
+	case ASN1_OP_MATCH_ANY_ACT:
+	case ASN1_OP_MATCH_ANY_ACT_OR_SKIP:
 	case ASN1_OP_COND_MATCH_OR_SKIP:
+	case ASN1_OP_COND_MATCH_ACT_OR_SKIP:
 	case ASN1_OP_COND_MATCH_ANY:
 	case ASN1_OP_COND_MATCH_ANY_OR_SKIP:
-	skip_data:
+	case ASN1_OP_COND_MATCH_ANY_ACT:
+	case ASN1_OP_COND_MATCH_ANY_ACT_OR_SKIP:
+
 		if (!(flags & FLAG_CONS)) {
 			if (flags & FLAG_INDEFINITE_LENGTH) {
+				size_t tmp = dp;
+
 				ret = asn1_find_indefinite_length(
-					data, datalen, &dp, &len, &errmsg);
+					data, datalen, &tmp, &len, &errmsg);
 				if (ret < 0)
 					goto error;
-			} else {
-				dp += len;
 			}
 			pr_debug("- LEAF: %zu\n", len);
 		}
+
+		if (op & ASN1_OP_MATCH__ACT) {
+			unsigned char act;
+
+			if (op & ASN1_OP_MATCH__ANY)
+				act = machine[pc + 1];
+			else
+				act = machine[pc + 2];
+			ret = actions[act](context, hdr, tag, data + dp, len);
+			if (ret < 0)
+				return ret;
+		}
+
+		if (!(flags & FLAG_CONS))
+			dp += len;
 		pc += asn1_op_lengths[op];
 		goto next_op;
 
@@ -377,6 +381,8 @@ next_op:
 	case ASN1_OP_END_SET_ACT:
 		if (unlikely(!(flags & FLAG_MATCHED)))
 			goto tag_mismatch;
+		fallthrough;
+
 	case ASN1_OP_END_SEQ:
 	case ASN1_OP_END_SET_OF:
 	case ASN1_OP_END_SEQ_OF:
@@ -431,6 +437,8 @@ next_op:
 			else
 				act = machine[pc + 1];
 			ret = actions[act](context, hdr, 0, data + tdp, len);
+			if (ret < 0)
+				return ret;
 		}
 		pc += asn1_op_lengths[op];
 		goto next_op;
@@ -440,6 +448,8 @@ next_op:
 			pc += asn1_op_lengths[op];
 			goto next_op;
 		}
+		fallthrough;
+
 	case ASN1_OP_ACT:
 		ret = actions[machine[pc + 1]](context, hdr, tag, data + tdp, len);
 		if (ret < 0)
@@ -508,4 +518,5 @@ error:
 }
 EXPORT_SYMBOL_GPL(asn1_ber_decoder);
 
+MODULE_DESCRIPTION("Decoder for ASN.1 BER/DER/CER encoded bytestream");
 MODULE_LICENSE("GPL");