[Git][NTPsec/ntpsec][master] 3 commits: Add length checks to fix fuzzer 393742176

[Hal Murray (@hal.murray)]

Hal Murray pushed to branch master at NTPsec / ntpsec


Commits:
0a36941e by Hal Murray at 2025-05-01T22:32:56-07:00
Add length checks to fix fuzzer 393742176

Also fix nonce length checking.

- - - - -
2b9fa5f2 by Hal Murray at 2025-05-01T22:35:46-07:00
Remove unneeded zeroing -- let fuzzer find bugs

The zeroing shouldn't be necessary.
It might be masking a real bug.

- - - - -
8937bef3 by Hal Murray at 2025-05-01T22:43:26-07:00
Turn off default bit on sys_var_list (mode6)

sys_var_list returns a list of all the variables you can ask for.
It adds lots of clutter to rv 0

This area needs cleanup.  I think I added the DEF bit to all
slots when I cleaned up this area a while ago.

- - - - -


3 changed files:

- ntpd/ntp_control.c
- ntpd/nts_extens.c
- ntpd/nts_server.c


Changes:

=====================================
ntpd/ntp_control.c
=====================================
@@ -313,7 +313,7 @@ static const struct var sys_var[] = {
   Var_strP("version", RO|DEF, ntpd_version),
 
   Var_dbl("clk_wander", RO|DEF|ToPPM|DBL6, loop_data.clock_stability),
-  Var_special("sys_var_list", RO|DEF, vs_varlist),
+  Var_special("sys_var_list", RO, vs_varlist),
   Var_uint("tai", RO|DEF, sys_tai),
   Var_time("leapsec", RO|DEF|N_LEAP, lsig.ttime),
   Var_time("expire", RO|DEF|N_LEAP, lsig.etime),


=====================================
ntpd/nts_extens.c
=====================================
@@ -397,14 +397,18 @@ bool extens_client_recv(struct peer *peer, uint8_t *pkt, int lng) {
 			break;
 		    case NTS_AEEF:
 			adlength = buf.next-NTP_EX_HDR_LNG-pkt;  /* backup over header */
+			if (NTP_EX_U16_LNG*2 > length)
+				return false;        /* garbage packet */
 			noncelen = next_uint16(&buf);
 			outlen = next_uint16(&buf);
 			if (noncelen&3 || outlen&3)
-				return false;                 /* else round up */
+				return false;        /* else round up */
 			nonce = buf.next;
 			ciphertext = nonce+noncelen;
 			plaintext = ciphertext+CMAC_LENGTH;
-			outlen = buf.left-NONCE_LENGTH-CMAC_LENGTH;
+			if (noncelen+CMAC_LENGTH > length)
+				return false;        /* garbage packet */
+			outlen = buf.left-noncelen-CMAC_LENGTH;
 			//      printf("ECRa: %lu, %d\n", (long unsigned)outlen, noncelen);
 			ok = AES_SIV_Decrypt(wire_ctx,
 					     plaintext, &outlen,
@@ -416,8 +420,8 @@ bool extens_client_recv(struct peer *peer, uint8_t *pkt, int lng) {
 			if (!ok)
 				return false;
 			/* setup to process encrypted headers */
-			buf.next += NONCE_LENGTH+CMAC_LENGTH;
-			buf.left -= NONCE_LENGTH+CMAC_LENGTH;
+			buf.next += noncelen+CMAC_LENGTH;
+			buf.left -= noncelen+CMAC_LENGTH;
 			sawAEEF = true;
 			break;
 		    default:


=====================================
ntpd/nts_server.c
=====================================
@@ -381,10 +381,10 @@ bool nts_ke_request(SSL *ssl) {
 	 * Our cookies can be 104, 136, or 168 for AES_SIV_CMAC_xxx
 	 * 8*168 fits comfortably into 2K.
 	 */
-	uint8_t buff[2048] = {0};
-	uint8_t c2s[NTS_MAX_KEYLEN] = {0}, s2c[NTS_MAX_KEYLEN] = {0};
+	uint8_t buff[2048];
+	uint8_t c2s[NTS_MAX_KEYLEN], s2c[NTS_MAX_KEYLEN];
 	int aead = NO_AEAD, keylen;
-	struct BufCtl_t buf = {0, 0};
+	struct BufCtl_t buf;
 	int bytes_read, bytes_written;
 	int used;
 



View it on GitLab: https://gitlab.com/NTPsec/ntpsec/-/compare/3c42d068b51a4c859e0299fadd6f3970572c4da6...8937bef325b7cf04020499502bd6227f623bc87a

-- 
View it on GitLab: https://gitlab.com/NTPsec/ntpsec/-/compare/3c42d068b51a4c859e0299fadd6f3970572c4da6...8937bef325b7cf04020499502bd6227f623bc87a
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