Fix sctp privilege elevation (CVE-2006-3745)

sctp_make_abort_user() now takes the msg_len along with the msg
so that we don't have to recalculate the bytes in iovec.
It also uses memcpy_fromiovec() so that we don't go beyond the
length allocated.

It is good to have this fix even if verify_iovec() is fixed to
return error on overflow.

Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 1 insertions, 15 deletions

diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index a9663b49ea54..92eae0e0f3f1 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -404,19 +404,6 @@ static inline int sctp_list_single_entry(struct list_head *head)
         return ((head->next != head) && (head->next == head->prev));
 }
 
-/* Calculate the size (in bytes) occupied by the data of an iovec.  */
-static inline size_t get_user_iov_size(struct iovec *iov, int iovlen)
-{
-        size_t retval = 0;
-
-        for (; iovlen > 0; --iovlen) {
-                retval += iov->iov_len;
-                iov++;
-        }
-
-        return retval;
-}
-
 /* Generate a random jitter in the range of -50% ~ +50% of input RTO. */
 static inline __s32 sctp_jitter(__u32 rto)
 {
diff --git a/include/net/sctp/sm.h b/include/net/sctp/sm.h
index 1eac3d0eb7a9..de313de4fefe 100644
--- a/include/net/sctp/sm.h
+++ b/include/net/sctp/sm.h
@@ -221,8 +221,7 @@ struct sctp_chunk *sctp_make_abort_no_data(const struct sctp_association *,
                                       const struct sctp_chunk *,
                                       __u32 tsn);
 struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *,
-                                   const struct sctp_chunk *,
-                                   const struct msghdr *);
+                                        const struct msghdr *, size_t msg_len);
 struct sctp_chunk *sctp_make_abort_violation(const struct sctp_association *,
                                    const struct sctp_chunk *,
                                    const __u8 *,