Merge pull request #4391 from JacobBarthelmeh/Sniffer

add sanity check on buffer size

wolfcrypt/src/asn.c

@@ -26838,6 +26838,9 @@ static int DecodeAsymKey(const byte* input, word32* inOutIdx, word32 inSz,
         endKeyIdx = *inOutIdx;
     }
 
+    if ((word32)privSz > *privKeyLen)
+        return BUFFER_E;
+
     if (endKeyIdx == (int)*inOutIdx) {
         *privKeyLen = privSz;
         XMEMCPY(privKey, priv, *privKeyLen);
@@ -26845,6 +26848,10 @@ static int DecodeAsymKey(const byte* input, word32* inOutIdx, word32 inSz,
             *pubKeyLen = 0;
     }
     else {
+        if (pubKeyLen == NULL) {
+            return BAD_FUNC_ARG;
+        }
+
         if (GetASNHeader(input, ASN_CONTEXT_SPECIFIC | ASN_CONSTRUCTED | 1,
                          inOutIdx, &length, inSz) < 0) {
             return ASN_PARSE_E;
@@ -26852,6 +26859,10 @@ static int DecodeAsymKey(const byte* input, word32* inOutIdx, word32 inSz,
         if (GetOctetString(input, inOutIdx, &pubSz, inSz) < 0) {
             return ASN_PARSE_E;
         }
+
+        if ((word32)pubSz > *pubKeyLen)
+            return BUFFER_E;
+
         pub = input + *inOutIdx;
         *inOutIdx += pubSz;
 
@@ -26949,6 +26960,10 @@ static int DecodeAsymKeyPublic(const byte* input, word32* inOutIdx, word32 inSz,
     if (ret != 0)
         return ret;
 
+    /* check that the value found is not too large for pubKey buffer */
+    if (inSz - *inOutIdx > *pubKeyLen)
+        return ASN_PARSE_E;
+
     /* This is the raw point data compressed or uncompressed. */
     *pubKeyLen = inSz - *inOutIdx;
     XMEMCPY(pubKey, input + *inOutIdx, *pubKeyLen);

wolfcrypt/test/test.c

@@ -26042,6 +26042,20 @@ WOLFSSL_TEST_SUBROUTINE int ed25519_test(void)
         0x44,0x49,0xc5,0x69,0x7b,0x32,0x69,0x19,
         0x70,0x3b,0xac,0x03,0x1c,0xae,0x7f,0x60
     };
+    static byte badPrivateEd25519[] = {
+        0x30,0x52,0x02,0x01,0x00,0x30,0x05,0x06,
+        0x03,0x2b,0x65,0x70,0x04,0x22,0x04,0x20,
+        0x9d,0x61,0xb1,0x9d,0xef,0xfd,0x5a,0x60,
+        0xba,0x84,0x4a,0xf4,0x92,0xec,0x2c,0xc4,
+        0x44,0x49,0xc5,0x69,0x7b,0x32,0x69,0x19,
+        0x70,0x3b,0xac,0x03,0x1c,0xae,0x7f,0x60,
+        0xa1,0x22,0x04,0x21,0xd7,0x5a,0x98,0x01, /* octet len 0x20 -> 0x21 */
+        0x82,0xb1,0x0a,0xb7,0xd5,0x4b,0xfe,0xd3,
+        0xc9,0x64,0x07,0x3a,0x0e,0xe1,0x72,0xf3,
+        0xda,0xa6,0x23,0x25,0xaf,0x02,0x1a,0x68,
+        0xf7,0x07,0x51,0x1a,
+        0x00  /* add additional bytes to make the pubkey bigger  */
+    };
     static byte publicEd25519[] = {
         0x30,0x2a,0x30,0x05,0x06,0x03,0x2b,0x65,
         0x70,0x03,0x21,0x00,0xd7,0x5a,0x98,0x01,
@@ -26050,6 +26064,17 @@ WOLFSSL_TEST_SUBROUTINE int ed25519_test(void)
         0xda,0xa6,0x23,0x25,0xaf,0x02,0x1a,0x68,
         0xf7,0x07,0x51,0x1a
     };
+
+    /* size has been altered to catch if sanity check is done */
+    static byte badPublicEd25519[] = {
+        0x30,0x2a,0x30,0x05,0x06,0x03,0x2b,0x65,
+        0x70,0x03,0x21,0x00,0xd7,0x5a,0x98,0x01,
+        0x82,0xb1,0x0a,0xb7,0xd5,0x4b,0xfe,0xd3,
+        0xc9,0x64,0x07,0x3a,0x0e,0xe1,0x72,0xf3,
+        0xda,0xa6,0x23,0x25,0xaf,0x02,0x1a,0x68,
+        0xf7,0x07,0x51,0x1a,
+        0x00 /* add an additional byte to make the pubkey appear bigger */
+    };
     static byte privPubEd25519[] = {
         0x30,0x52,0x02,0x01,0x00,0x30,0x05,0x06,
         0x03,0x2b,0x65,0x70,0x04,0x22,0x04,0x20,
@@ -26182,10 +26207,22 @@ WOLFSSL_TEST_SUBROUTINE int ed25519_test(void)
                                    sizeof(privateEd25519)) != 0)
         return -11121;
 
+    idx = 0;
+    if (wc_Ed25519PrivateKeyDecode(badPrivateEd25519, &idx, &key3,
+                                   sizeof(badPrivateEd25519)) == 0)
+        return -11122;
+
     if (wc_ed25519_sign_msg(msgs[0], msgSz[0], out, &outlen, &key3)
                 != BAD_FUNC_ARG)
         return -11131;
 
+
+    /* try with a buffer size that is too large */
+    idx = 0;
+    if (wc_Ed25519PublicKeyDecode(badPublicEd25519, &idx, &key3,
+                                  sizeof(badPublicEd25519)) == 0)
+        return -11140;
+
     idx = 0;
     if (wc_Ed25519PublicKeyDecode(publicEd25519, &idx, &key3,
                                   sizeof(publicEd25519)) != 0)