This is a note to let you know that I've just added the patch titled
CIFS: Fix too big maxBuf size for SMB3 mounts
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
cifs-fix-too-big-maxbuf-size-for-smb3-mounts.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2365c4eaf077c48574ab6f143960048fc0f31518 Mon Sep 17 00:00:00 2001
From: Pavel Shilovsky <piastry@xxxxxxxxxxx>
Date: Fri, 14 Feb 2014 13:31:02 +0400
Subject: CIFS: Fix too big maxBuf size for SMB3 mounts
From: Pavel Shilovsky <piastry@xxxxxxxxxxx>
commit 2365c4eaf077c48574ab6f143960048fc0f31518 upstream.
SMB3 servers can respond with MaxTransactSize of more than 4M
that can cause a memory allocation error returned from kmalloc
in a lock codepath. Also the client doesn't support multicredit
requests now and allows buffer sizes of 65536 bytes only. Set
MaxTransactSize to this maximum supported value.
Signed-off-by: Pavel Shilovsky <piastry@xxxxxxxxxxx>
Acked-by: Jeff Layton <jlayton@xxxxxxxxxx>
Signed-off-by: Steve French <smfrench@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/cifs/smb2glob.h | 3 +++
fs/cifs/smb2ops.c | 14 ++++----------
fs/cifs/smb2pdu.c | 3 +++
3 files changed, 10 insertions(+), 10 deletions(-)
--- a/fs/cifs/smb2glob.h
+++ b/fs/cifs/smb2glob.h
@@ -55,4 +55,7 @@
#define SMB2_NTLMV2_SESSKEY_SIZE (16)
#define SMB2_HMACSHA256_SIZE (32)
+/* Maximum buffer size value we can send with 1 credit */
+#define SMB2_MAX_BUFFER_SIZE 65536
+
#endif /* _SMB2_GLOB_H */
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -181,11 +181,8 @@ smb2_negotiate_wsize(struct cifs_tcon *t
/* start with specified wsize, or default */
wsize = volume_info->wsize ? volume_info->wsize : CIFS_DEFAULT_IOSIZE;
wsize = min_t(unsigned int, wsize, server->max_write);
- /*
- * limit write size to 2 ** 16, because we don't support multicredit
- * requests now.
- */
- wsize = min_t(unsigned int, wsize, 2 << 15);
+ /* set it to the maximum buffer size value we can send with 1 credit */
+ wsize = min_t(unsigned int, wsize, SMB2_MAX_BUFFER_SIZE);
return wsize;
}
@@ -199,11 +196,8 @@ smb2_negotiate_rsize(struct cifs_tcon *t
/* start with specified rsize, or default */
rsize = volume_info->rsize ? volume_info->rsize : CIFS_DEFAULT_IOSIZE;
rsize = min_t(unsigned int, rsize, server->max_read);
- /*
- * limit write size to 2 ** 16, because we don't support multicredit
- * requests now.
- */
- rsize = min_t(unsigned int, rsize, 2 << 15);
+ /* set it to the maximum buffer size value we can send with 1 credit */
+ rsize = min_t(unsigned int, rsize, SMB2_MAX_BUFFER_SIZE);
return rsize;
}
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -408,6 +408,9 @@ SMB2_negotiate(const unsigned int xid, s
server->dialect = le16_to_cpu(rsp->DialectRevision);
server->maxBuf = le32_to_cpu(rsp->MaxTransactSize);
+ /* set it to the maximum buffer size value we can send with 1 credit */
+ server->maxBuf = min_t(unsigned int, le32_to_cpu(rsp->MaxTransactSize),
+ SMB2_MAX_BUFFER_SIZE);
server->max_read = le32_to_cpu(rsp->MaxReadSize);
server->max_write = le32_to_cpu(rsp->MaxWriteSize);
/* BB Do we need to validate the SecurityMode? */
Patches currently in stable-queue which might be from piastry@xxxxxxxxxxx are
queue-3.10/cifs-fix-too-big-maxbuf-size-for-smb3-mounts.patch
queue-3.10/cifs-ensure-that-uncached-writes-handle-unmapped-areas-correctly.patch
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