| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.13 096/223] sctp: trim optlen when its a huge value in sctp_setsockopt | Date | Mon, 26 Jul 2021 17:38:08 +0200 |
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From: Xin Long <lucien.xin@gmail.com>
[ Upstream commit 2f3fdd8d4805015fa964807e1c7f3d88f31bd389 ]
After commit ca84bd058dae ("sctp: copy the optval from user space in sctp_setsockopt"), it does memory allocation in sctp_setsockopt with the optlen, and it would fail the allocation and return error if the optlen from user space is a huge value.
This breaks some sockopts, like SCTP_HMAC_IDENT, SCTP_RESET_STREAMS and SCTP_AUTH_KEY, as when processing these sockopts before, optlen would be trimmed to a biggest value it needs when optlen is a huge value, instead of failing the allocation and returning error.
This patch is to fix the allocation failure when it's a huge optlen from user space by trimming it to the biggest size sctp sockopt may need when necessary, and this biggest size is from sctp_setsockopt_reset_streams() for SCTP_RESET_STREAMS, which is bigger than those for SCTP_HMAC_IDENT and SCTP_AUTH_KEY.
Fixes: ca84bd058dae ("sctp: copy the optval from user space in sctp_setsockopt") Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> --- net/sctp/socket.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/net/sctp/socket.c b/net/sctp/socket.c index a79d193ff872..dbd074f4d450 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -4521,6 +4521,10 @@ static int sctp_setsockopt(struct sock *sk, int level, int optname, } if (optlen > 0) { + /* Trim it to the biggest size sctp sockopt may need if necessary */ + optlen = min_t(unsigned int, optlen, + PAGE_ALIGN(USHRT_MAX + + sizeof(__u16) * sizeof(struct sctp_reset_streams))); kopt = memdup_sockptr(optval, optlen); if (IS_ERR(kopt)) return PTR_ERR(kopt); -- 2.30.2
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