From: Kees Cook Date: Wed, 14 Feb 2018 23:45:07 +0000 (-0800) Subject: NFC: llcp: Limit size of SDP URI X-Git-Tag: v4.9.104~213 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=69b28c18f7c8b3bbdc037f1cc029acc21723b997;p=thirdparty%2Fkernel%2Fstable.git NFC: llcp: Limit size of SDP URI [ Upstream commit fe9c842695e26d8116b61b80bfb905356f07834b ] The tlv_len is u8, so we need to limit the size of the SDP URI. Enforce this both in the NLA policy and in the code that performs the allocation and copy, to avoid writing past the end of the allocated buffer. Fixes: d9b8d8e19b073 ("NFC: llcp: Service Name Lookup netlink interface") Signed-off-by: Kees Cook Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/nfc/llcp_commands.c b/net/nfc/llcp_commands.c index c5959ce503e6c..3f266115294f1 100644 --- a/net/nfc/llcp_commands.c +++ b/net/nfc/llcp_commands.c @@ -149,6 +149,10 @@ struct nfc_llcp_sdp_tlv *nfc_llcp_build_sdreq_tlv(u8 tid, char *uri, pr_debug("uri: %s, len: %zu\n", uri, uri_len); + /* sdreq->tlv_len is u8, takes uri_len, + 3 for header, + 1 for NULL */ + if (WARN_ON_ONCE(uri_len > U8_MAX - 4)) + return NULL; + sdreq = kzalloc(sizeof(struct nfc_llcp_sdp_tlv), GFP_KERNEL); if (sdreq == NULL) return NULL; diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c index 102c681c48b50..dbf74afe82fb6 100644 --- a/net/nfc/netlink.c +++ b/net/nfc/netlink.c @@ -68,7 +68,8 @@ static const struct nla_policy nfc_genl_policy[NFC_ATTR_MAX + 1] = { }; static const struct nla_policy nfc_sdp_genl_policy[NFC_SDP_ATTR_MAX + 1] = { - [NFC_SDP_ATTR_URI] = { .type = NLA_STRING }, + [NFC_SDP_ATTR_URI] = { .type = NLA_STRING, + .len = U8_MAX - 4 }, [NFC_SDP_ATTR_SAP] = { .type = NLA_U8 }, };