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Commit 2b7566af authored by Kees Cook's avatar Kees Cook Committed by TARKZiM
Browse files

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: d9b8d8e1 ("NFC: llcp: Service Name Lookup netlink interface")
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <alexander.levin@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent cc60ad48

net/nfc/llcp_commands.c

+4 −0
Original line number Diff line number Diff line
@@ -151,6 +151,10 @@ 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;

net/nfc/netlink.c

+2 −1
Original line number Diff line number Diff line
@@ -59,7 +59,8 @@ 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 },

};