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Commit 5960cefa authored by Marcelo Ricardo Leitner's avatar Marcelo Ricardo Leitner Committed by David S. Miller
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sctp: add a ceiling to optlen in some sockopts 



Hangbin Liu reported that some sockopt calls could cause the kernel to log
a warning on memory allocation failure if the user supplied a large optlen
value. That is because some of them called memdup_user() without a ceiling
on optlen, allowing it to try to allocate really large buffers.

This patch adds a ceiling by limiting optlen to the maximum allowed that
would still make sense for these sockopt.

Reported-by: default avatarHangbin Liu <haliu@redhat.com>
Signed-off-by: default avatarMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2e83acb9

net/sctp/socket.c

+10 −0
Original line number Diff line number Diff line
@@ -3498,6 +3498,8 @@ static int sctp_setsockopt_hmac_ident(struct sock *sk, 


	if (optlen < sizeof(struct sctp_hmacalgo))

		return -EINVAL;

	optlen = min_t(unsigned int, optlen, sizeof(struct sctp_hmacalgo) +

					     SCTP_AUTH_NUM_HMACS * sizeof(u16));



	hmacs = memdup_user(optval, optlen);

	if (IS_ERR(hmacs))
@@ -3536,6 +3538,11 @@ static int sctp_setsockopt_auth_key(struct sock *sk, 


	if (optlen <= sizeof(struct sctp_authkey))

		return -EINVAL;

	/* authkey->sca_keylength is u16, so optlen can't be bigger than

	 * this.

	 */

	optlen = min_t(unsigned int, optlen, USHRT_MAX +

					     sizeof(struct sctp_authkey));



	authkey = memdup_user(optval, optlen);

	if (IS_ERR(authkey))
@@ -3893,6 +3900,9 @@ static int sctp_setsockopt_reset_streams(struct sock *sk, 


	if (optlen < sizeof(*params))

		return -EINVAL;

	/* srs_number_streams is u16, so optlen can't be bigger than this. */

	optlen = min_t(unsigned int, optlen, USHRT_MAX +

					     sizeof(__u16) * sizeof(*params));



	params = memdup_user(optval, optlen);

	if (IS_ERR(params))