| From 2365c4eaf077c48574ab6f143960048fc0f31518 Mon Sep 17 00:00:00 2001 |
| From: Pavel Shilovsky <piastry@etersoft.ru> |
| Date: Fri, 14 Feb 2014 13:31:02 +0400 |
| Subject: CIFS: Fix too big maxBuf size for SMB3 mounts |
| |
| From: Pavel Shilovsky <piastry@etersoft.ru> |
| |
| 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@etersoft.ru> |
| Acked-by: Jeff Layton <jlayton@redhat.com> |
| Signed-off-by: Steve French <smfrench@gmail.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/cifs/smb2glob.h | 3 +++ |
| fs/cifs/smb2ops.c | 14 ++++---------- |
| fs/cifs/smb2pdu.c | 4 +++- |
| 3 files changed, 10 insertions(+), 11 deletions(-) |
| |
| --- a/fs/cifs/smb2glob.h |
| +++ b/fs/cifs/smb2glob.h |
| @@ -57,4 +57,7 @@ |
| #define SMB2_CMACAES_SIZE (16) |
| #define SMB3_SIGNKEY_SIZE (16) |
| |
| +/* 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 |
| @@ -182,11 +182,8 @@ 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; |
| } |
| @@ -200,11 +197,8 @@ 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 |
| @@ -413,7 +413,9 @@ SMB2_negotiate(const unsigned int xid, s |
| |
| /* SMB2 only has an extended negflavor */ |
| server->negflavor = CIFS_NEGFLAVOR_EXTENDED; |
| - 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? */ |
