Re: [syzbot] [net?] KASAN: slab-out-of-bounds Read in dns_resolver_preparse
From: syzbot <hidden>
Date: 2023-12-23 23:17:22
Also in:
keyrings, lkml, netdev
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
want either no args or 2 args (repo, branch), got 5
quoted hunk ↗ jump to hunk
diff --git a/net/dns_resolver/dns_key.c b/net/dns_resolver/dns_key.c index 2a6d363763a2..f18ca02aa95a 100644 --- a/net/dns_resolver/dns_key.c +++ b/net/dns_resolver/dns_key.c@@ -91,8 +91,6 @@ const struct cred *dns_resolver_cache; static int dns_resolver_preparse(struct key_preparsed_payload *prep) { - const struct dns_server_list_v1_header *v1; - const struct dns_payload_header *bin; struct user_key_payload *upayload; unsigned long derrno; int ret;@@ -103,27 +101,28 @@ dns_resolver_preparse(struct key_preparsed_payload *prep) return -EINVAL; if (data[0] == 0) { + const struct dns_server_list_v1_header *v1; + /* It may be a server list. */ - if (datalen <= sizeof(*bin)) + if (datalen <= sizeof(*v1)) return -EINVAL; - bin = (const struct dns_payload_header *)data; - kenter("[%u,%u],%u", bin->content, bin->version, datalen); - if (bin->content != DNS_PAYLOAD_IS_SERVER_LIST) { + v1 = (const struct dns_server_list_v1_header *)data; + kenter("[%u,%u],%u", v1->hdr.content, v1->hdr.version, datalen); + if (v1->hdr.content != DNS_PAYLOAD_IS_SERVER_LIST) { pr_warn_ratelimited( "dns_resolver: Unsupported content type (%u)\n", - bin->content); + v1->hdr.content); return -EINVAL; } - if (bin->version != 1) { + if (v1->hdr.version != 1) { pr_warn_ratelimited( "dns_resolver: Unsupported server list version (%u)\n", - bin->version); + v1->hdr.version); return -EINVAL; } - v1 = (const struct dns_server_list_v1_header *)bin; if ((v1->status != DNS_LOOKUP_GOOD && v1->status != DNS_LOOKUP_GOOD_WITH_BAD)) { if (prep->expiry == TIME64_MAX)