@@ -811,13 +811,9 @@ cifs_read_iter_from_socket(struct TCP_Server_Info *server, struct iov_iter *iter
unsigned int to_read)
{
struct msghdr smb_msg = { .msg_iter = *iter };
- int ret;
iov_iter_truncate(&smb_msg.msg_iter, to_read);
- ret = cifs_readv_from_socket(server, &smb_msg);
- if (ret > 0)
- iov_iter_advance(iter, ret);
- return ret;
+ return cifs_readv_from_socket(server, &smb_msg);
}
static bool
@@ -4869,9 +4869,12 @@ receive_encrypted_read(struct TCP_Server_Info *server, struct mid_q_entry **mid,
goto discard_data;
server->total_read += rc;
- if (rc < len)
- iov_iter_zero(len - rc, &iter);
- iov_iter_revert(&iter, len);
+ if (rc < len) {
+ struct iov_iter tmp = iter;
+
+ iov_iter_advance(&tmp, rc);
+ iov_iter_zero(len - rc, &tmp);
+ }
iov_iter_truncate(&iter, dw->len);
rc = cifs_discard_remaining_data(server);
@@ -1817,11 +1817,8 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
length = data_len; /* An RDMA read is already done. */
else
#endif
- {
length = cifs_read_iter_from_socket(server, &rdata->subreq.io_iter,
data_len);
- iov_iter_revert(&rdata->subreq.io_iter, data_len);
- }
if (length > 0)
rdata->got_bytes += length;
server->total_read += length;
cifs_read_iter_from_socket() copies the iterator that's passed in for the socket to modify as and if it will, and then advances the original iterator by the amount sent. However, both callers revert the advancement (although receive_encrypted_read() zeros beyond the iterator first). The problem is, though, that cifs_readv_receive() reverts by the original length, not the amount transmitted which can cause an oops in iov_iter_revert(). Fix this by: (1) Remove the iov_iter_advance() from cifs_read_iter_from_socket(). (2) Remove the iov_iter_revert() from both callers. This fixes the bug in cifs_readv_receive(). (3) In receive_encrypted_read(), if we didn't get back as much data as the buffer will hold, copy the iterator, advance the copy and use the copy to drive iov_iter_zero(). As a bonus, this gets rid of some unnecessary work. This was triggered by generic/074 with the "-o sign" mount option. Fixes: 3ee1a1fc3981 ("cifs: Cut over to using netfslib") Signed-off-by: David Howells <dhowells@redhat.com> cc: Steve French <sfrench@samba.org> cc: Paulo Alcantara <pc@manguebit.com> cc: Shyam Prasad N <nspmangalore@gmail.com> cc: Rohith Surabattula <rohiths.msft@gmail.com> cc: Jeff Layton <jlayton@kernel.org> cc: linux-cifs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org --- fs/smb/client/connect.c | 6 +----- fs/smb/client/smb2ops.c | 9 ++++++--- fs/smb/client/transport.c | 3 --- 3 files changed, 7 insertions(+), 11 deletions(-)