[patch 30/42] sctp: correct bounds check insctp_setsockopt_auth_key

From: Greg KH
Date: Wed Sep 03 2008 - 13:43:30 EST


2.6.26-stable review patch. If anyone has any objections, please let us know.

------------------

From: Vlad Yasevich <vladislav.yasevich@xxxxxx>

[ Upstream commit 328fc47ea0bcc27d9afa69c3ad6e52431cadd76c ]

The bonds check to prevent buffer overlflow was not exactly
right. It still allowed overflow of up to 8 bytes which is
sizeof(struct sctp_authkey).

Since optlen is already checked against the size of that struct,
we are guaranteed not to cause interger overflow either.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@xxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
net/sctp/socket.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -3054,7 +3054,7 @@ static int sctp_setsockopt_auth_key(stru
goto out;
}

- if (authkey->sca_keylength > optlen) {
+ if (authkey->sca_keylength > optlen - sizeof(struct sctp_authkey)) {
ret = -EINVAL;
goto out;
}

--
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