Commit 5960cefa authored by Marcelo Ricardo Leitner's avatar Marcelo Ricardo Leitner Committed by David S. Miller

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
...@@ -3498,6 +3498,8 @@ static int sctp_setsockopt_hmac_ident(struct sock *sk, ...@@ -3498,6 +3498,8 @@ static int sctp_setsockopt_hmac_ident(struct sock *sk,
if (optlen < sizeof(struct sctp_hmacalgo)) if (optlen < sizeof(struct sctp_hmacalgo))
return -EINVAL; return -EINVAL;
optlen = min_t(unsigned int, optlen, sizeof(struct sctp_hmacalgo) +
SCTP_AUTH_NUM_HMACS * sizeof(u16));
hmacs = memdup_user(optval, optlen); hmacs = memdup_user(optval, optlen);
if (IS_ERR(hmacs)) if (IS_ERR(hmacs))
...@@ -3536,6 +3538,11 @@ static int sctp_setsockopt_auth_key(struct sock *sk, ...@@ -3536,6 +3538,11 @@ static int sctp_setsockopt_auth_key(struct sock *sk,
if (optlen <= sizeof(struct sctp_authkey)) if (optlen <= sizeof(struct sctp_authkey))
return -EINVAL; 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); authkey = memdup_user(optval, optlen);
if (IS_ERR(authkey)) if (IS_ERR(authkey))
...@@ -3893,6 +3900,9 @@ static int sctp_setsockopt_reset_streams(struct sock *sk, ...@@ -3893,6 +3900,9 @@ static int sctp_setsockopt_reset_streams(struct sock *sk,
if (optlen < sizeof(*params)) if (optlen < sizeof(*params))
return -EINVAL; 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); params = memdup_user(optval, optlen);
if (IS_ERR(params)) if (IS_ERR(params))
......
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