⬢ DragonFlyBSD Kernel Audit
DF-2364 / fix.diff
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--- a/sys/crypto/chachapoly.c
+++ b/sys/crypto/chachapoly.c
@@ -74,6 +74,9 @@
 	/* Initialize the authenticator. */
 	poly1305_init(&ctx->poly, poly_key);
 
+	/* wipe the one-time key from the stack (DF-2363) */
+	explicit_bzero(poly_key, sizeof(poly_key));
+
 	ctx->flags |= (enc_mode ? F_MODE_ENCRYPTION : 0);
 	ctx->flags |= F_INITIALIZED;
 }
@@ -113,6 +116,8 @@
 	KKASSERT((ctx->flags & F_INITIALIZED) != 0);
 	KKASSERT(in_len == 0 || (in_len > 0 && out != NULL));
 	KKASSERT(in_len % CHACHA_BLOCKLEN == 0); /* must be complete blocks */
+	/* chacha_encrypt_bytes() takes a uint32_t byte count (DF-2364) */
+	KKASSERT(in_len <= 0xffffffffU);
 
 	if ((ctx->flags & F_AD_DONE) == 0) {
 		poly1305_update(&ctx->poly, pad0, PADDING_LEN(ctx->ad_len));
@@ -313,8 +318,10 @@
 			/* Skip possibly empty mbufs. */
 			while (m != NULL && m->m_len == 0)
 				m = m->m_next;
-			if (m == NULL)
+			if (m == NULL) {
+				explicit_bzero(ctx, sizeof(*ctx));
 				return (EINVAL); /* because len > 0 */
+			}
 		}
 
 		if (m->m_len >= off + sizeof(block)) {
@@ -334,8 +341,10 @@
 
 			/* Advance pointer. */
 			m = m_getptr(m, off + sizeof(block), &off);
-			if (m == NULL)
+			if (m == NULL) {
+				explicit_bzero(ctx, sizeof(*ctx));
 				return (EINVAL);
+			}
 
 			len -= (int)sizeof(block);
 		}