diff options
| author | Jeff Layton <jlayton@redhat.com> | 2014-02-14 07:21:00 -0500 |
|---|---|---|
| committer | Steve French <smfrench@gmail.com> | 2014-02-23 20:55:07 -0600 |
| commit | a26054d184763969a411e3939fe243516715ff59 (patch) | |
| tree | 949134388a332f66f28a80d329263031e7136d43 | |
| parent | 6b1168e1617d9d4db73ef5276490627abf5adec4 (diff) | |
cifs: sanity check length of data to send before sending
We had a bug discovered recently where an upper layer function
(cifs_iovec_write) could pass down a smb_rqst with an invalid amount of
data in it. The length of the SMB frame would be correct, but the rqst
struct would cause smb_send_rqst to send nearly 4GB of data.
This should never be the case. Add some sanity checking to the beginning
of smb_send_rqst that ensures that the amount of data we're going to
send agrees with the length in the RFC1002 header. If it doesn't, WARN()
and return -EIO to the upper layers.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Sachin Prabhu <sprabhu@redhat.com>
Reviewed-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <smfrench@gmail.com>
| -rw-r--r-- | fs/cifs/transport.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c index b3757095284..18cd5650a5f 100644 --- a/fs/cifs/transport.c +++ b/fs/cifs/transport.c @@ -270,6 +270,26 @@ cifs_rqst_page_to_kvec(struct smb_rqst *rqst, unsigned int idx, iov->iov_len = rqst->rq_pagesz; } +static unsigned long +rqst_len(struct smb_rqst *rqst) +{ + unsigned int i; + struct kvec *iov = rqst->rq_iov; + unsigned long buflen = 0; + + /* total up iov array first */ + for (i = 0; i < rqst->rq_nvec; i++) + buflen += iov[i].iov_len; + + /* add in the page array if there is one */ + if (rqst->rq_npages) { + buflen += rqst->rq_pagesz * (rqst->rq_npages - 1); + buflen += rqst->rq_tailsz; + } + + return buflen; +} + static int smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst) { @@ -277,6 +297,7 @@ smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst) struct kvec *iov = rqst->rq_iov; int n_vec = rqst->rq_nvec; unsigned int smb_buf_length = get_rfc1002_length(iov[0].iov_base); + unsigned long send_length; unsigned int i; size_t total_len = 0, sent; struct socket *ssocket = server->ssocket; @@ -285,6 +306,14 @@ smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst) if (ssocket == NULL) return -ENOTSOCK; + /* sanity check send length */ + send_length = rqst_len(rqst); + if (send_length != smb_buf_length + 4) { + WARN(1, "Send length mismatch(send_length=%lu smb_buf_length=%u)\n", + send_length, smb_buf_length); + return -EIO; + } + cifs_dbg(FYI, "Sending smb: smb_len=%u\n", smb_buf_length); dump_smb(iov[0].iov_base, iov[0].iov_len); |