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authorJeff Layton <jlayton@redhat.com>2008-02-06 01:36:43 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-06 10:41:02 -0800
commitce88cc5ed80de746f5bd2d8242291c87e7b87f63 (patch)
treeac0c1890d0f741a33c6e2cd41712ae3200bf38ea /fs/smbfs
parent941e492bdb1239d2ca8f5736cdfd3ff83d00cb90 (diff)
downloadlinux-linaro-ce88cc5ed80de746f5bd2d8242291c87e7b87f63.tar.gz
smbfs: fix calculation of kernel_recvmsg size parameter in smb_receive()
smb_receive calls kernel_recvmsg with a size that's the minimum of the amount of buffer space in the kvec passed in or req->rq_rlen (which represents the length of the response). This does not take into account any data that was read in a request earlier pass through smb_receive. If the first pass through smb_receive receives some but not all of the response, then the next pass can call kernel_recvmsg with a size field that's too big. kernel_recvmsg can overrun into the next response, throwing off the alignment and making it unrecognizable. This causes messages like this to pop up in the ring buffer: smb_get_length: Invalid NBT packet, code=69 as well as other errors indicating that the response is unrecognizable. Typically this is seen on a smbfs mount under heavy I/O. This patch changes the code to use (req->rq_rlen - req->rq_bytes_recvd) instead instead of just req->rq_rlen, since that should represent the amount of unread data in the response. I think this is correct, but an ACK or NACK from someone more familiar with this code would be appreciated... Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/smbfs')
-rw-r--r--fs/smbfs/sock.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/fs/smbfs/sock.c b/fs/smbfs/sock.c
index e48bd8235a8..e37fe4deebd 100644
--- a/fs/smbfs/sock.c
+++ b/fs/smbfs/sock.c
@@ -329,9 +329,8 @@ smb_receive(struct smb_sb_info *server, struct smb_request *req)
msg.msg_control = NULL;
/* Dont repeat bytes and count available bufferspace */
- rlen = smb_move_iov(&p, &num, iov, req->rq_bytes_recvd);
- if (req->rq_rlen < rlen)
- rlen = req->rq_rlen;
+ rlen = min_t(int, smb_move_iov(&p, &num, iov, req->rq_bytes_recvd),
+ (req->rq_rlen - req->rq_bytes_recvd));
result = kernel_recvmsg(sock, &msg, p, num, rlen, flags);