newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode)
{
	struct sshbuf *b = NULL;
	struct sshcomp *comp;
	struct sshenc *enc;
	struct sshmac *mac;
	struct newkeys *newkey = NULL;
	size_t keylen, ivlen, maclen;
	int r;

	if ((newkey = calloc(1, sizeof(*newkey))) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	if ((r = sshbuf_froms(m, &b)) != 0)
		goto out;
#ifdef DEBUG_PK
	sshbuf_dump(b, stderr);
#endif
	enc = &newkey->enc;
	mac = &newkey->mac;
	comp = &newkey->comp;

	if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 ||
	    (r = sshbuf_get(b, &enc->cipher, sizeof(enc->cipher))) != 0 ||
	    (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 ||
	    (r = sshbuf_get_u32(b, &enc->block_size)) != 0 ||
	    (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 ||
	    (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0)
		goto out;
	if (cipher_authlen(enc->cipher) == 0) {
		if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0)
			goto out;
		if ((r = mac_setup(mac, mac->name)) != 0)
			goto out;
		if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 ||
		    (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0)
			goto out;
		if (maclen > mac->key_len) {
			r = SSH_ERR_INVALID_FORMAT;
			goto out;
		}
		mac->key_len = maclen;
	}
	if ((r = sshbuf_get_u32(b, &comp->type)) != 0 ||
	    (r = sshbuf_get_u32(b, (u_int *)&comp->enabled)) != 0 ||
	    (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0)
		goto out;
	if (enc->name == NULL ||
	    cipher_by_name(enc->name) != enc->cipher) {
		r = SSH_ERR_INVALID_FORMAT;
		goto out;
	}
	if (sshbuf_len(b) != 0) {
		r = SSH_ERR_INVALID_FORMAT;
		goto out;
	}
	enc->key_len = keylen;
	enc->iv_len = ivlen;
	ssh->kex->newkeys[mode] = newkey;
	newkey = NULL;
	r = 0;
 out:
	if (newkey != NULL)
		free(newkey);
	if (b != NULL)
		sshbuf_free(b);
	return r;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.