This is a note to let you know that I've just added the patch titled

sctp: add a ceiling to optlen in some sockopts

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: sctp-add-a-ceiling-to-optlen-in-some-sockopts.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Wed Feb 28 16:23:28 CET 2018

From: Marcelo Ricardo Leitner marcelo.leitner@gmail.com Date: Mon, 8 Jan 2018 19:02:28 -0200 Subject: sctp: add a ceiling to optlen in some sockopts

From: Marcelo Ricardo Leitner marcelo.leitner@gmail.com

[ Upstream commit 5960cefab9df76600a1a7d4ff592c59e14616e88 ]

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 Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sctp/socket.c | 10 ++++++++++ 1 file changed, 10 insertions(+)

--- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -3494,6 +3494,8 @@ static int sctp_setsockopt_hmac_ident(st

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)) @@ -3532,6 +3534,11 @@ static int sctp_setsockopt_auth_key(stru

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)) @@ -3889,6 +3896,9 @@ static int sctp_setsockopt_reset_streams

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))

Patches currently in stable-queue which might be from marcelo.leitner@gmail.com are

queue-4.14/sctp-make-use-of-pre-calculated-len.patch queue-4.14/sctp-add-a-ceiling-to-optlen-in-some-sockopts.patch queue-4.14/sctp-fix-the-issue-that-a-__u16-variable-may-overflow-in-sctp_ulpq_renege.patch