diff mbox

CIFS: Fix too big maxBuf size for SMB3 mounts

Message ID 1392370263-10364-1-git-send-email-piastry@etersoft.ru (mailing list archive)
State New, archived
Headers show

Commit Message

Pavel Shilovsky Feb. 14, 2014, 9:31 a.m. UTC
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.

Cc: stable@vger.kernel.org # 3.7+
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
---
 fs/cifs/smb2glob.h |    3 +++
 fs/cifs/smb2ops.c  |   14 ++++----------
 fs/cifs/smb2pdu.c  |    4 +++-
 3 files changed, 10 insertions(+), 11 deletions(-)

Comments

Jeff Layton Feb. 14, 2014, 7:10 p.m. UTC | #1
On Fri, 14 Feb 2014 13:31:02 +0400
Pavel Shilovsky <piastry@etersoft.ru> wrote:

> 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.
> 
> Cc: stable@vger.kernel.org # 3.7+
> Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
> ---
>  fs/cifs/smb2glob.h |    3 +++
>  fs/cifs/smb2ops.c  |   14 ++++----------
>  fs/cifs/smb2pdu.c  |    4 +++-
>  3 files changed, 10 insertions(+), 11 deletions(-)
> 
> diff --git a/fs/cifs/smb2glob.h b/fs/cifs/smb2glob.h
> index c383508..bc0bb9c 100644
> --- 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 */
> diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> index 757da3e..192f51a 100644
> --- a/fs/cifs/smb2ops.c
> +++ b/fs/cifs/smb2ops.c
> @@ -182,11 +182,8 @@ smb2_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *volume_info)
>  	/* 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 *tcon, struct smb_vol *volume_info)
>  	/* 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;
>  }
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index 2013234..787e171 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -413,7 +413,9 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
>  
>  	/* 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? */

Acked-by: Jeff Layton <jlayton@redhat.com>
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Steve French Feb. 14, 2014, 10:51 p.m. UTC | #2
Merged into cifs-2.6.git for-next

On Fri, Feb 14, 2014 at 3:31 AM, Pavel Shilovsky <piastry@etersoft.ru> wrote:
> 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.
>
> Cc: stable@vger.kernel.org # 3.7+
> Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
> ---
>  fs/cifs/smb2glob.h |    3 +++
>  fs/cifs/smb2ops.c  |   14 ++++----------
>  fs/cifs/smb2pdu.c  |    4 +++-
>  3 files changed, 10 insertions(+), 11 deletions(-)
>
> diff --git a/fs/cifs/smb2glob.h b/fs/cifs/smb2glob.h
> index c383508..bc0bb9c 100644
> --- 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 */
> diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> index 757da3e..192f51a 100644
> --- a/fs/cifs/smb2ops.c
> +++ b/fs/cifs/smb2ops.c
> @@ -182,11 +182,8 @@ smb2_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *volume_info)
>         /* 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 *tcon, struct smb_vol *volume_info)
>         /* 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;
>  }
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index 2013234..787e171 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -413,7 +413,9 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
>
>         /* 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? */
> --
> 1.7.10.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-cifs" in
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diff mbox

Patch

diff --git a/fs/cifs/smb2glob.h b/fs/cifs/smb2glob.h
index c383508..bc0bb9c 100644
--- 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 */
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 757da3e..192f51a 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -182,11 +182,8 @@  smb2_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *volume_info)
 	/* 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 *tcon, struct smb_vol *volume_info)
 	/* 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;
 }
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 2013234..787e171 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -413,7 +413,9 @@  SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
 
 	/* 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? */