sctp: add a ceiling to optlen in some sockopts (5960cefa) · Commits · 戴 / test

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:

Hangbin Liu <haliu@redhat.com> Signed-off-by:

Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

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))

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