From: Xin Long lucien.xin@gmail.com
stable inclusion from stable-5.10.54 commit 096a8dca8ca5191292bcc6409c552a7b7f5e7362 bugzilla: 175586 https://gitee.com/openeuler/kernel/issues/I4DVDU
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ 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 Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com Signed-off-by: Chen Jun chenjun102@huawei.com --- net/sctp/socket.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 3ac6b21ecf2c..e872bc50bbe6 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -4471,6 +4471,10 @@ 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);