[v2,2/6] cifs: Allocate validate negotiation request through kmalloc

Message ID 20180417191710.14855-2-longli@linuxonhyperv.com
State New
Headers show
Series
  • [v2,1/6] cifs: smbd: Check for iov length on sending the last iov
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Commit Message

Long Li April 17, 2018, 7:17 p.m.
From: Long Li <longli@microsoft.com>

The data buffer allocated on the stack can't be DMA'ed, and hence can't send
through RDMA via SMB Direct.

Fix this by allocating the request on the heap in smb3_validate_negotiate.

Fixes: ff1c038addc4f205d5f1ede449426c7d316c0eed "Check SMB3 dialects against
downgrade attacks"

Changes in v2:
Removed duplicated code on freeing buffers on function exit.
(Thanks to Parav Pandit <parav@mellanox.com>)

Fixed typo in the patch title.

Signed-off-by: Long Li <longli@microsoft.com>
Cc: stable@vger.kernel.org
---
 fs/cifs/smb2pdu.c | 57 ++++++++++++++++++++++++++++++-------------------------
 1 file changed, 31 insertions(+), 26 deletions(-)

Comments

Parav Pandit April 17, 2018, 7:59 p.m. | #1
> -----Original Message-----
> From: linux-rdma-owner@vger.kernel.org [mailto:linux-rdma-
> owner@vger.kernel.org] On Behalf Of Long Li
> Sent: Tuesday, April 17, 2018 2:17 PM
> To: Steve French <sfrench@samba.org>; linux-cifs@vger.kernel.org; samba-
> technical@lists.samba.org; linux-kernel@vger.kernel.org; linux-
> rdma@vger.kernel.org
> Cc: longli <longli@microsoft.com>; stable@vger.kernel.org
> Subject: [Patch v2 2/6] cifs: Allocate validate negotiation request through
> kmalloc
> 
> From: Long Li <longli@microsoft.com>
> 
> The data buffer allocated on the stack can't be DMA'ed, and hence can't send
> through RDMA via SMB Direct.
> 
> Fix this by allocating the request on the heap in smb3_validate_negotiate.
> 
> Fixes: ff1c038addc4f205d5f1ede449426c7d316c0eed "Check SMB3 dialects
> against downgrade attacks"
> 

Format is:
Fixes: ff1c038addc4 ("Check SMB3 dialects against downgrade attacks")
It should be right above Signed-off signature.

> Changes in v2:
> Removed duplicated code on freeing buffers on function exit.
> (Thanks to Parav Pandit <parav@mellanox.com>)
> 
> Fixed typo in the patch title.
> 
> Signed-off-by: Long Li <longli@microsoft.com>
> Cc: stable@vger.kernel.org
> ---
>  fs/cifs/smb2pdu.c | 57 ++++++++++++++++++++++++++++++------------------------
> -
>  1 file changed, 31 insertions(+), 26 deletions(-)
> 
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 0f044c4..41625e4
> 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -729,8 +729,8 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses
> *ses)
> 
>  int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)  {
> -	int rc = 0;
> -	struct validate_negotiate_info_req vneg_inbuf;
> +	int ret, rc = -EIO;
> +	struct validate_negotiate_info_req *pneg_inbuf;
>  	struct validate_negotiate_info_rsp *pneg_rsp = NULL;
>  	u32 rsplen;
>  	u32 inbuflen; /* max of 4 dialects */
> @@ -741,6 +741,9 @@ int smb3_validate_negotiate(const unsigned int xid,
> struct cifs_tcon *tcon)
>  	if (tcon->ses->server->rdma)
>  		return 0;
>  #endif
> +	pneg_inbuf = kmalloc(sizeof(*pneg_inbuf), GFP_KERNEL);
> +	if (!pneg_inbuf)
> +		return -ENOMEM;
> 
>  	/* In SMB3.11 preauth integrity supersedes validate negotiate */
>  	if (tcon->ses->server->dialect == SMB311_PROT_ID) @@ -764,53
> +767,53 @@ int smb3_validate_negotiate(const unsigned int xid, struct
> cifs_tcon *tcon)
>  	if (tcon->ses->session_flags & SMB2_SESSION_FLAG_IS_NULL)
>  		cifs_dbg(VFS, "Unexpected null user (anonymous) auth flag sent
> by server\n");
> 
> -	vneg_inbuf.Capabilities =
> +	pneg_inbuf->Capabilities =
>  			cpu_to_le32(tcon->ses->server->vals-
> >req_capabilities);
> -	memcpy(vneg_inbuf.Guid, tcon->ses->server->client_guid,
> +	memcpy(pneg_inbuf->Guid, tcon->ses->server->client_guid,
>  					SMB2_CLIENT_GUID_SIZE);
> 
>  	if (tcon->ses->sign)
> -		vneg_inbuf.SecurityMode =
> +		pneg_inbuf->SecurityMode =
>  			cpu_to_le16(SMB2_NEGOTIATE_SIGNING_REQUIRED);
>  	else if (global_secflags & CIFSSEC_MAY_SIGN)
> -		vneg_inbuf.SecurityMode =
> +		pneg_inbuf->SecurityMode =
>  			cpu_to_le16(SMB2_NEGOTIATE_SIGNING_ENABLED);
>  	else
> -		vneg_inbuf.SecurityMode = 0;
> +		pneg_inbuf->SecurityMode = 0;
> 
> 
>  	if (strcmp(tcon->ses->server->vals->version_string,
Please check if strncmp() should be used or not.

>  		SMB3ANY_VERSION_STRING) == 0) {
> -		vneg_inbuf.Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
> -		vneg_inbuf.Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
> -		vneg_inbuf.DialectCount = cpu_to_le16(2);
> +		pneg_inbuf->Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
> +		pneg_inbuf->Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
> +		pneg_inbuf->DialectCount = cpu_to_le16(2);
>  		/* structure is big enough for 3 dialects, sending only 2 */
>  		inbuflen = sizeof(struct validate_negotiate_info_req) - 2;
>  	} else if (strcmp(tcon->ses->server->vals->version_string,
>  		SMBDEFAULT_VERSION_STRING) == 0) {
> -		vneg_inbuf.Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
> -		vneg_inbuf.Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
> -		vneg_inbuf.Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
> -		vneg_inbuf.DialectCount = cpu_to_le16(3);
> +		pneg_inbuf->Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
> +		pneg_inbuf->Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
> +		pneg_inbuf->Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
> +		pneg_inbuf->DialectCount = cpu_to_le16(3);
>  		/* structure is big enough for 3 dialects */
>  		inbuflen = sizeof(struct validate_negotiate_info_req);
>  	} else {
>  		/* otherwise specific dialect was requested */
> -		vneg_inbuf.Dialects[0] =
> +		pneg_inbuf->Dialects[0] =
>  			cpu_to_le16(tcon->ses->server->vals->protocol_id);
> -		vneg_inbuf.DialectCount = cpu_to_le16(1);
> +		pneg_inbuf->DialectCount = cpu_to_le16(1);
>  		/* structure is big enough for 3 dialects, sending only 1 */
>  		inbuflen = sizeof(struct validate_negotiate_info_req) - 4;
>  	}
> 
> -	rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
> +	ret = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
>  		FSCTL_VALIDATE_NEGOTIATE_INFO, true /* is_fsctl */,
> -		(char *)&vneg_inbuf, sizeof(struct
> validate_negotiate_info_req),
> +		(char *)pneg_inbuf, sizeof(struct validate_negotiate_info_req),

Use sizeof(*pneg_inbuf)

>  		(char **)&pneg_rsp, &rsplen);
> 
> -	if (rc != 0) {
> -		cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", rc);
> -		return -EIO;
> +	if (ret != 0) {

if (ret) is fine.

> +		cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", ret);
> +		goto out_free_inbuf;
>  	}
> 
>  	if (rsplen != sizeof(struct validate_negotiate_info_rsp)) { @@ -820,7

if (rsplen != sizeof(*pneg_rsp))

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Long Li April 17, 2018, 8:11 p.m. | #2
> Subject: RE: [Patch v2 2/6] cifs: Allocate validate negotiation request through
> kmalloc
> 
> 
> 
> > -----Original Message-----
> > From: linux-rdma-owner@vger.kernel.org [mailto:linux-rdma-
> > owner@vger.kernel.org] On Behalf Of Long Li
> > Sent: Tuesday, April 17, 2018 2:17 PM
> > To: Steve French <sfrench@samba.org>; linux-cifs@vger.kernel.org;
> > samba- technical@lists.samba.org; linux-kernel@vger.kernel.org; linux-
> > rdma@vger.kernel.org
> > Cc: longli <longli@microsoft.com>; stable@vger.kernel.org
> > Subject: [Patch v2 2/6] cifs: Allocate validate negotiation request
> > through kmalloc
> >
> > From: Long Li <longli@microsoft.com>
> >
> > The data buffer allocated on the stack can't be DMA'ed, and hence
> > can't send through RDMA via SMB Direct.
> >
> > Fix this by allocating the request on the heap in smb3_validate_negotiate.
> >
> > Fixes: ff1c038addc4f205d5f1ede449426c7d316c0eed "Check SMB3 dialects
> > against downgrade attacks"
> >
> 
> Format is:
> Fixes: ff1c038addc4 ("Check SMB3 dialects against downgrade attacks") It
> should be right above Signed-off signature.

I will fix up and resend this patch.

How about the rest patches (1, 3-6) in the series? If they don't need any changes, is it okay that I resend this one only?

> 
> > Changes in v2:
> > Removed duplicated code on freeing buffers on function exit.
> > (Thanks to Parav Pandit <parav@mellanox.com>)
> >
> > Fixed typo in the patch title.
> >
> > Signed-off-by: Long Li <longli@microsoft.com>
> > Cc: stable@vger.kernel.org
> > ---
> >  fs/cifs/smb2pdu.c | 57
> > ++++++++++++++++++++++++++++++------------------------
> > -
> >  1 file changed, 31 insertions(+), 26 deletions(-)
> >
> > diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index
> > 0f044c4..41625e4
> > 100644
> > --- a/fs/cifs/smb2pdu.c
> > +++ b/fs/cifs/smb2pdu.c
> > @@ -729,8 +729,8 @@ SMB2_negotiate(const unsigned int xid, struct
> > cifs_ses
> > *ses)
> >
> >  int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
> {
> > -	int rc = 0;
> > -	struct validate_negotiate_info_req vneg_inbuf;
> > +	int ret, rc = -EIO;
> > +	struct validate_negotiate_info_req *pneg_inbuf;
> >  	struct validate_negotiate_info_rsp *pneg_rsp = NULL;
> >  	u32 rsplen;
> >  	u32 inbuflen; /* max of 4 dialects */ @@ -741,6 +741,9 @@ int
> > smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon
> > *tcon)
> >  	if (tcon->ses->server->rdma)
> >  		return 0;
> >  #endif
> > +	pneg_inbuf = kmalloc(sizeof(*pneg_inbuf), GFP_KERNEL);
> > +	if (!pneg_inbuf)
> > +		return -ENOMEM;
> >
> >  	/* In SMB3.11 preauth integrity supersedes validate negotiate */
> >  	if (tcon->ses->server->dialect == SMB311_PROT_ID) @@ -764,53
> > +767,53 @@ int smb3_validate_negotiate(const unsigned int xid, struct
> > cifs_tcon *tcon)
> >  	if (tcon->ses->session_flags & SMB2_SESSION_FLAG_IS_NULL)
> >  		cifs_dbg(VFS, "Unexpected null user (anonymous) auth flag
> sent by
> > server\n");
> >
> > -	vneg_inbuf.Capabilities =
> > +	pneg_inbuf->Capabilities =
> >  			cpu_to_le32(tcon->ses->server->vals-
> > >req_capabilities);
> > -	memcpy(vneg_inbuf.Guid, tcon->ses->server->client_guid,
> > +	memcpy(pneg_inbuf->Guid, tcon->ses->server->client_guid,
> >  					SMB2_CLIENT_GUID_SIZE);
> >
> >  	if (tcon->ses->sign)
> > -		vneg_inbuf.SecurityMode =
> > +		pneg_inbuf->SecurityMode =
> >
> 	cpu_to_le16(SMB2_NEGOTIATE_SIGNING_REQUIRED);
> >  	else if (global_secflags & CIFSSEC_MAY_SIGN)
> > -		vneg_inbuf.SecurityMode =
> > +		pneg_inbuf->SecurityMode =
> >
> 	cpu_to_le16(SMB2_NEGOTIATE_SIGNING_ENABLED);
> >  	else
> > -		vneg_inbuf.SecurityMode = 0;
> > +		pneg_inbuf->SecurityMode = 0;
> >
> >
> >  	if (strcmp(tcon->ses->server->vals->version_string,
> Please check if strncmp() should be used or not.
> 
> >  		SMB3ANY_VERSION_STRING) == 0) {
> > -		vneg_inbuf.Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
> > -		vneg_inbuf.Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
> > -		vneg_inbuf.DialectCount = cpu_to_le16(2);
> > +		pneg_inbuf->Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
> > +		pneg_inbuf->Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
> > +		pneg_inbuf->DialectCount = cpu_to_le16(2);
> >  		/* structure is big enough for 3 dialects, sending only 2 */
> >  		inbuflen = sizeof(struct validate_negotiate_info_req) - 2;
> >  	} else if (strcmp(tcon->ses->server->vals->version_string,
> >  		SMBDEFAULT_VERSION_STRING) == 0) {
> > -		vneg_inbuf.Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
> > -		vneg_inbuf.Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
> > -		vneg_inbuf.Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
> > -		vneg_inbuf.DialectCount = cpu_to_le16(3);
> > +		pneg_inbuf->Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
> > +		pneg_inbuf->Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
> > +		pneg_inbuf->Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
> > +		pneg_inbuf->DialectCount = cpu_to_le16(3);
> >  		/* structure is big enough for 3 dialects */
> >  		inbuflen = sizeof(struct validate_negotiate_info_req);
> >  	} else {
> >  		/* otherwise specific dialect was requested */
> > -		vneg_inbuf.Dialects[0] =
> > +		pneg_inbuf->Dialects[0] =
> >  			cpu_to_le16(tcon->ses->server->vals->protocol_id);
> > -		vneg_inbuf.DialectCount = cpu_to_le16(1);
> > +		pneg_inbuf->DialectCount = cpu_to_le16(1);
> >  		/* structure is big enough for 3 dialects, sending only 1 */
> >  		inbuflen = sizeof(struct validate_negotiate_info_req) - 4;
> >  	}
> >
> > -	rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
> > +	ret = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
> >  		FSCTL_VALIDATE_NEGOTIATE_INFO, true /* is_fsctl */,
> > -		(char *)&vneg_inbuf, sizeof(struct
> > validate_negotiate_info_req),
> > +		(char *)pneg_inbuf, sizeof(struct
> validate_negotiate_info_req),
> 
> Use sizeof(*pneg_inbuf)
> 
> >  		(char **)&pneg_rsp, &rsplen);
> >
> > -	if (rc != 0) {
> > -		cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", rc);
> > -		return -EIO;
> > +	if (ret != 0) {
> 
> if (ret) is fine.
> 
> > +		cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", ret);
> > +		goto out_free_inbuf;
> >  	}
> >
> >  	if (rsplen != sizeof(struct validate_negotiate_info_rsp)) { @@
> > -820,7
> 
> if (rsplen != sizeof(*pneg_rsp))

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Steve French April 17, 2018, 8:37 p.m. | #3
On Tue, Apr 17, 2018 at 3:11 PM, Long Li via samba-technical
<samba-technical@lists.samba.org> wrote:
>> Subject: RE: [Patch v2 2/6] cifs: Allocate validate negotiation request through
>> kmalloc
>>
>>
>>
>> > -----Original Message-----
>> > From: linux-rdma-owner@vger.kernel.org [mailto:linux-rdma-
>> > owner@vger.kernel.org] On Behalf Of Long Li
>> > Sent: Tuesday, April 17, 2018 2:17 PM
>> > To: Steve French <sfrench@samba.org>; linux-cifs@vger.kernel.org;
>> > samba- technical@lists.samba.org; linux-kernel@vger.kernel.org; linux-
>> > rdma@vger.kernel.org
>> > Cc: longli <longli@microsoft.com>; stable@vger.kernel.org
>> > Subject: [Patch v2 2/6] cifs: Allocate validate negotiation request
>> > through kmalloc
>> >
>> > From: Long Li <longli@microsoft.com>
>> >
>> > The data buffer allocated on the stack can't be DMA'ed, and hence
>> > can't send through RDMA via SMB Direct.
>> >
>> > Fix this by allocating the request on the heap in smb3_validate_negotiate.
>> >
>> > Fixes: ff1c038addc4f205d5f1ede449426c7d316c0eed "Check SMB3 dialects
>> > against downgrade attacks"
>> >
>>
>> Format is:
>> Fixes: ff1c038addc4 ("Check SMB3 dialects against downgrade attacks") It
>> should be right above Signed-off signature.
>
> I will fix up and resend this patch.
>
> How about the rest patches (1, 3-6) in the series? If they don't need any changes, is it okay that I resend this one only?

Doesn't matter to me either way - I already merged patch 1 in any case.

>> > Changes in v2:
>> > Removed duplicated code on freeing buffers on function exit.
>> > (Thanks to Parav Pandit <parav@mellanox.com>)
Michael Kelley (EOSG) April 19, 2018, 12:45 a.m. | #4
> -----Original Message-----
> From: linux-kernel-owner@vger.kernel.org <linux-kernel-owner@vger.kernel.org> On Behalf
> Of Long Li
> Sent: Tuesday, April 17, 2018 12:17 PM
> To: Steve French <sfrench@samba.org>; linux-cifs@vger.kernel.org; samba-
> technical@lists.samba.org; linux-kernel@vger.kernel.org; linux-rdma@vger.kernel.org
> Cc: Long Li <longli@microsoft.com>; stable@vger.kernel.org
> Subject: [Patch v2 2/6] cifs: Allocate validate negotiation request through kmalloc
> 
> From: Long Li <longli@microsoft.com>
> 
> The data buffer allocated on the stack can't be DMA'ed, and hence can't send
> through RDMA via SMB Direct.
> 
> Fix this by allocating the request on the heap in smb3_validate_negotiate.
> 
> Fixes: ff1c038addc4f205d5f1ede449426c7d316c0eed "Check SMB3 dialects against
> downgrade attacks"
> 
> Changes in v2:
> Removed duplicated code on freeing buffers on function exit.
> (Thanks to Parav Pandit <parav@mellanox.com>)
> 
> Fixed typo in the patch title.
> 
> Signed-off-by: Long Li <longli@microsoft.com>
> Cc: stable@vger.kernel.org
> ---
>  fs/cifs/smb2pdu.c | 57 ++++++++++++++++++++++++++++++-------------------------
>  1 file changed, 31 insertions(+), 26 deletions(-)
> 
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index 0f044c4..41625e4 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -729,8 +729,8 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
> 
>  int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
>  {
> -	int rc = 0;
> -	struct validate_negotiate_info_req vneg_inbuf;
> +	int ret, rc = -EIO;
> +	struct validate_negotiate_info_req *pneg_inbuf;
>  	struct validate_negotiate_info_rsp *pneg_rsp = NULL;
>  	u32 rsplen;
>  	u32 inbuflen; /* max of 4 dialects */
> @@ -741,6 +741,9 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon
> *tcon)
>  	if (tcon->ses->server->rdma)
>  		return 0;
>  #endif
> +	pneg_inbuf = kmalloc(sizeof(*pneg_inbuf), GFP_KERNEL);
> +	if (!pneg_inbuf)
> +		return -ENOMEM;

Immediately after the above new code, there are three if statements that can
'return 0' and never free the pneg_inbuf memory.  They should instead set 'rc'
appropriately and 'goto' the out_free_inbuf label.

Michael

> 
>  	/* In SMB3.11 preauth integrity supersedes validate negotiate */
>  	if (tcon->ses->server->dialect == SMB311_PROT_ID)
> @@ -764,53 +767,53 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon
> *tcon)
>  	if (tcon->ses->session_flags & SMB2_SESSION_FLAG_IS_NULL)
>  		cifs_dbg(VFS, "Unexpected null user (anonymous) auth flag sent by server\n");
> 
> -	vneg_inbuf.Capabilities =
> +	pneg_inbuf->Capabilities =
>  			cpu_to_le32(tcon->ses->server->vals->req_capabilities);
> -	memcpy(vneg_inbuf.Guid, tcon->ses->server->client_guid,
> +	memcpy(pneg_inbuf->Guid, tcon->ses->server->client_guid,
>  					SMB2_CLIENT_GUID_SIZE);
> 
>  	if (tcon->ses->sign)
> -		vneg_inbuf.SecurityMode =
> +		pneg_inbuf->SecurityMode =
>  			cpu_to_le16(SMB2_NEGOTIATE_SIGNING_REQUIRED);
>  	else if (global_secflags & CIFSSEC_MAY_SIGN)
> -		vneg_inbuf.SecurityMode =
> +		pneg_inbuf->SecurityMode =
>  			cpu_to_le16(SMB2_NEGOTIATE_SIGNING_ENABLED);
>  	else
> -		vneg_inbuf.SecurityMode = 0;
> +		pneg_inbuf->SecurityMode = 0;
> 
> 
>  	if (strcmp(tcon->ses->server->vals->version_string,
>  		SMB3ANY_VERSION_STRING) == 0) {
> -		vneg_inbuf.Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
> -		vneg_inbuf.Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
> -		vneg_inbuf.DialectCount = cpu_to_le16(2);
> +		pneg_inbuf->Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
> +		pneg_inbuf->Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
> +		pneg_inbuf->DialectCount = cpu_to_le16(2);
>  		/* structure is big enough for 3 dialects, sending only 2 */
>  		inbuflen = sizeof(struct validate_negotiate_info_req) - 2;
>  	} else if (strcmp(tcon->ses->server->vals->version_string,
>  		SMBDEFAULT_VERSION_STRING) == 0) {
> -		vneg_inbuf.Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
> -		vneg_inbuf.Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
> -		vneg_inbuf.Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
> -		vneg_inbuf.DialectCount = cpu_to_le16(3);
> +		pneg_inbuf->Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
> +		pneg_inbuf->Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
> +		pneg_inbuf->Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
> +		pneg_inbuf->DialectCount = cpu_to_le16(3);
>  		/* structure is big enough for 3 dialects */
>  		inbuflen = sizeof(struct validate_negotiate_info_req);
>  	} else {
>  		/* otherwise specific dialect was requested */
> -		vneg_inbuf.Dialects[0] =
> +		pneg_inbuf->Dialects[0] =
>  			cpu_to_le16(tcon->ses->server->vals->protocol_id);
> -		vneg_inbuf.DialectCount = cpu_to_le16(1);
> +		pneg_inbuf->DialectCount = cpu_to_le16(1);
>  		/* structure is big enough for 3 dialects, sending only 1 */
>  		inbuflen = sizeof(struct validate_negotiate_info_req) - 4;
>  	}
> 
> -	rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
> +	ret = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
>  		FSCTL_VALIDATE_NEGOTIATE_INFO, true /* is_fsctl */,
> -		(char *)&vneg_inbuf, sizeof(struct validate_negotiate_info_req),
> +		(char *)pneg_inbuf, sizeof(struct validate_negotiate_info_req),
>  		(char **)&pneg_rsp, &rsplen);
> 
> -	if (rc != 0) {
> -		cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", rc);
> -		return -EIO;
> +	if (ret != 0) {
> +		cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", ret);
> +		goto out_free_inbuf;
>  	}
> 
>  	if (rsplen != sizeof(struct validate_negotiate_info_rsp)) {
> @@ -820,7 +823,7 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon
> *tcon)
>  		/* relax check since Mac returns max bufsize allowed on ioctl */
>  		if ((rsplen > CIFSMaxBufSize)
>  		     || (rsplen < sizeof(struct validate_negotiate_info_rsp)))
> -			goto err_rsp_free;
> +			goto out_free_rsp;
>  	}
> 
>  	/* check validate negotiate info response matches what we got earlier */
> @@ -838,14 +841,16 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon
> *tcon)
> 
>  	/* validate negotiate successful */
>  	cifs_dbg(FYI, "validate negotiate info successful\n");
> -	kfree(pneg_rsp);
> -	return 0;
> +	rc = 0;
> +	goto out_free_rsp;
> 
>  vneg_out:
>  	cifs_dbg(VFS, "protocol revalidation - security settings mismatch\n");
> -err_rsp_free:
> +out_free_rsp:
>  	kfree(pneg_rsp);
> -	return -EIO;
> +out_free_inbuf:
> +	kfree(pneg_inbuf);
> +	return rc;
>  }
> 
>  enum securityEnum
> --
> 2.7.4

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Long Li April 19, 2018, 12:48 a.m. | #5
> Subject: RE: [Patch v2 2/6] cifs: Allocate validate negotiation request through
> kmalloc
> 
> > -----Original Message-----
> > From: linux-kernel-owner@vger.kernel.org
> > <linux-kernel-owner@vger.kernel.org> On Behalf Of Long Li
> > Sent: Tuesday, April 17, 2018 12:17 PM
> > To: Steve French <sfrench@samba.org>; linux-cifs@vger.kernel.org;
> > samba- technical@lists.samba.org; linux-kernel@vger.kernel.org;
> > linux-rdma@vger.kernel.org
> > Cc: Long Li <longli@microsoft.com>; stable@vger.kernel.org
> > Subject: [Patch v2 2/6] cifs: Allocate validate negotiation request
> > through kmalloc
> >
> > From: Long Li <longli@microsoft.com>
> >
> > The data buffer allocated on the stack can't be DMA'ed, and hence
> > can't send through RDMA via SMB Direct.
> >
> > Fix this by allocating the request on the heap in smb3_validate_negotiate.
> >
> > Fixes: ff1c038addc4f205d5f1ede449426c7d316c0eed "Check SMB3 dialects
> > against downgrade attacks"
> >
> > Changes in v2:
> > Removed duplicated code on freeing buffers on function exit.
> > (Thanks to Parav Pandit <parav@mellanox.com>)
> >
> > Fixed typo in the patch title.
> >
> > Signed-off-by: Long Li <longli@microsoft.com>
> > Cc: stable@vger.kernel.org
> > ---
> >  fs/cifs/smb2pdu.c | 57
> > ++++++++++++++++++++++++++++++-------------------------
> >  1 file changed, 31 insertions(+), 26 deletions(-)
> >
> > diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index
> > 0f044c4..41625e4 100644
> > --- a/fs/cifs/smb2pdu.c
> > +++ b/fs/cifs/smb2pdu.c
> > @@ -729,8 +729,8 @@ SMB2_negotiate(const unsigned int xid, struct
> > cifs_ses *ses)
> >
> >  int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon
> > *tcon)  {
> > -	int rc = 0;
> > -	struct validate_negotiate_info_req vneg_inbuf;
> > +	int ret, rc = -EIO;
> > +	struct validate_negotiate_info_req *pneg_inbuf;
> >  	struct validate_negotiate_info_rsp *pneg_rsp = NULL;
> >  	u32 rsplen;
> >  	u32 inbuflen; /* max of 4 dialects */ @@ -741,6 +741,9 @@ int
> > smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon
> > *tcon)
> >  	if (tcon->ses->server->rdma)
> >  		return 0;
> >  #endif
> > +	pneg_inbuf = kmalloc(sizeof(*pneg_inbuf), GFP_KERNEL);
> > +	if (!pneg_inbuf)
> > +		return -ENOMEM;
> 
> Immediately after the above new code, there are three if statements that
> can 'return 0' and never free the pneg_inbuf memory.  They should instead
> set 'rc'
> appropriately and 'goto' the out_free_inbuf label.

Thanks!

I will move the kmalloc after those statements.

> 
> Michael
> 
> >
> >  	/* In SMB3.11 preauth integrity supersedes validate negotiate */
> >  	if (tcon->ses->server->dialect == SMB311_PROT_ID) @@ -764,53
> +767,53
> > @@ int smb3_validate_negotiate(const unsigned int xid, struct
> > cifs_tcon
> > *tcon)
> >  	if (tcon->ses->session_flags & SMB2_SESSION_FLAG_IS_NULL)
> >  		cifs_dbg(VFS, "Unexpected null user (anonymous) auth flag
> sent by
> > server\n");
> >
> > -	vneg_inbuf.Capabilities =
> > +	pneg_inbuf->Capabilities =
> >  			cpu_to_le32(tcon->ses->server->vals-
> >req_capabilities);
> > -	memcpy(vneg_inbuf.Guid, tcon->ses->server->client_guid,
> > +	memcpy(pneg_inbuf->Guid, tcon->ses->server->client_guid,
> >  					SMB2_CLIENT_GUID_SIZE);
> >
> >  	if (tcon->ses->sign)
> > -		vneg_inbuf.SecurityMode =
> > +		pneg_inbuf->SecurityMode =
> >
> 	cpu_to_le16(SMB2_NEGOTIATE_SIGNING_REQUIRED);
> >  	else if (global_secflags & CIFSSEC_MAY_SIGN)
> > -		vneg_inbuf.SecurityMode =
> > +		pneg_inbuf->SecurityMode =
> >
> 	cpu_to_le16(SMB2_NEGOTIATE_SIGNING_ENABLED);
> >  	else
> > -		vneg_inbuf.SecurityMode = 0;
> > +		pneg_inbuf->SecurityMode = 0;
> >
> >
> >  	if (strcmp(tcon->ses->server->vals->version_string,
> >  		SMB3ANY_VERSION_STRING) == 0) {
> > -		vneg_inbuf.Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
> > -		vneg_inbuf.Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
> > -		vneg_inbuf.DialectCount = cpu_to_le16(2);
> > +		pneg_inbuf->Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
> > +		pneg_inbuf->Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
> > +		pneg_inbuf->DialectCount = cpu_to_le16(2);
> >  		/* structure is big enough for 3 dialects, sending only 2 */
> >  		inbuflen = sizeof(struct validate_negotiate_info_req) - 2;
> >  	} else if (strcmp(tcon->ses->server->vals->version_string,
> >  		SMBDEFAULT_VERSION_STRING) == 0) {
> > -		vneg_inbuf.Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
> > -		vneg_inbuf.Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
> > -		vneg_inbuf.Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
> > -		vneg_inbuf.DialectCount = cpu_to_le16(3);
> > +		pneg_inbuf->Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
> > +		pneg_inbuf->Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
> > +		pneg_inbuf->Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
> > +		pneg_inbuf->DialectCount = cpu_to_le16(3);
> >  		/* structure is big enough for 3 dialects */
> >  		inbuflen = sizeof(struct validate_negotiate_info_req);
> >  	} else {
> >  		/* otherwise specific dialect was requested */
> > -		vneg_inbuf.Dialects[0] =
> > +		pneg_inbuf->Dialects[0] =
> >  			cpu_to_le16(tcon->ses->server->vals->protocol_id);
> > -		vneg_inbuf.DialectCount = cpu_to_le16(1);
> > +		pneg_inbuf->DialectCount = cpu_to_le16(1);
> >  		/* structure is big enough for 3 dialects, sending only 1 */
> >  		inbuflen = sizeof(struct validate_negotiate_info_req) - 4;
> >  	}
> >
> > -	rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
> > +	ret = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
> >  		FSCTL_VALIDATE_NEGOTIATE_INFO, true /* is_fsctl */,
> > -		(char *)&vneg_inbuf, sizeof(struct
> validate_negotiate_info_req),
> > +		(char *)pneg_inbuf, sizeof(struct
> validate_negotiate_info_req),
> >  		(char **)&pneg_rsp, &rsplen);
> >
> > -	if (rc != 0) {
> > -		cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", rc);
> > -		return -EIO;
> > +	if (ret != 0) {
> > +		cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", ret);
> > +		goto out_free_inbuf;
> >  	}
> >
> >  	if (rsplen != sizeof(struct validate_negotiate_info_rsp)) { @@
> > -820,7 +823,7 @@ int smb3_validate_negotiate(const unsigned int xid,
> > struct cifs_tcon
> > *tcon)
> >  		/* relax check since Mac returns max bufsize allowed on ioctl
> */
> >  		if ((rsplen > CIFSMaxBufSize)
> >  		     || (rsplen < sizeof(struct validate_negotiate_info_rsp)))
> > -			goto err_rsp_free;
> > +			goto out_free_rsp;
> >  	}
> >
> >  	/* check validate negotiate info response matches what we got
> > earlier */ @@ -838,14 +841,16 @@ int smb3_validate_negotiate(const
> > unsigned int xid, struct cifs_tcon
> > *tcon)
> >
> >  	/* validate negotiate successful */
> >  	cifs_dbg(FYI, "validate negotiate info successful\n");
> > -	kfree(pneg_rsp);
> > -	return 0;
> > +	rc = 0;
> > +	goto out_free_rsp;
> >
> >  vneg_out:
> >  	cifs_dbg(VFS, "protocol revalidation - security settings
> > mismatch\n");
> > -err_rsp_free:
> > +out_free_rsp:
> >  	kfree(pneg_rsp);
> > -	return -EIO;
> > +out_free_inbuf:
> > +	kfree(pneg_inbuf);
> > +	return rc;
> >  }
> >
> >  enum securityEnum
> > --
> > 2.7.4

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Patch

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 0f044c4..41625e4 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -729,8 +729,8 @@  SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
 
 int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
 {
-	int rc = 0;
-	struct validate_negotiate_info_req vneg_inbuf;
+	int ret, rc = -EIO;
+	struct validate_negotiate_info_req *pneg_inbuf;
 	struct validate_negotiate_info_rsp *pneg_rsp = NULL;
 	u32 rsplen;
 	u32 inbuflen; /* max of 4 dialects */
@@ -741,6 +741,9 @@  int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
 	if (tcon->ses->server->rdma)
 		return 0;
 #endif
+	pneg_inbuf = kmalloc(sizeof(*pneg_inbuf), GFP_KERNEL);
+	if (!pneg_inbuf)
+		return -ENOMEM;
 
 	/* In SMB3.11 preauth integrity supersedes validate negotiate */
 	if (tcon->ses->server->dialect == SMB311_PROT_ID)
@@ -764,53 +767,53 @@  int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
 	if (tcon->ses->session_flags & SMB2_SESSION_FLAG_IS_NULL)
 		cifs_dbg(VFS, "Unexpected null user (anonymous) auth flag sent by server\n");
 
-	vneg_inbuf.Capabilities =
+	pneg_inbuf->Capabilities =
 			cpu_to_le32(tcon->ses->server->vals->req_capabilities);
-	memcpy(vneg_inbuf.Guid, tcon->ses->server->client_guid,
+	memcpy(pneg_inbuf->Guid, tcon->ses->server->client_guid,
 					SMB2_CLIENT_GUID_SIZE);
 
 	if (tcon->ses->sign)
-		vneg_inbuf.SecurityMode =
+		pneg_inbuf->SecurityMode =
 			cpu_to_le16(SMB2_NEGOTIATE_SIGNING_REQUIRED);
 	else if (global_secflags & CIFSSEC_MAY_SIGN)
-		vneg_inbuf.SecurityMode =
+		pneg_inbuf->SecurityMode =
 			cpu_to_le16(SMB2_NEGOTIATE_SIGNING_ENABLED);
 	else
-		vneg_inbuf.SecurityMode = 0;
+		pneg_inbuf->SecurityMode = 0;
 
 
 	if (strcmp(tcon->ses->server->vals->version_string,
 		SMB3ANY_VERSION_STRING) == 0) {
-		vneg_inbuf.Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
-		vneg_inbuf.Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
-		vneg_inbuf.DialectCount = cpu_to_le16(2);
+		pneg_inbuf->Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
+		pneg_inbuf->Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
+		pneg_inbuf->DialectCount = cpu_to_le16(2);
 		/* structure is big enough for 3 dialects, sending only 2 */
 		inbuflen = sizeof(struct validate_negotiate_info_req) - 2;
 	} else if (strcmp(tcon->ses->server->vals->version_string,
 		SMBDEFAULT_VERSION_STRING) == 0) {
-		vneg_inbuf.Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
-		vneg_inbuf.Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
-		vneg_inbuf.Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
-		vneg_inbuf.DialectCount = cpu_to_le16(3);
+		pneg_inbuf->Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
+		pneg_inbuf->Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
+		pneg_inbuf->Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
+		pneg_inbuf->DialectCount = cpu_to_le16(3);
 		/* structure is big enough for 3 dialects */
 		inbuflen = sizeof(struct validate_negotiate_info_req);
 	} else {
 		/* otherwise specific dialect was requested */
-		vneg_inbuf.Dialects[0] =
+		pneg_inbuf->Dialects[0] =
 			cpu_to_le16(tcon->ses->server->vals->protocol_id);
-		vneg_inbuf.DialectCount = cpu_to_le16(1);
+		pneg_inbuf->DialectCount = cpu_to_le16(1);
 		/* structure is big enough for 3 dialects, sending only 1 */
 		inbuflen = sizeof(struct validate_negotiate_info_req) - 4;
 	}
 
-	rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
+	ret = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
 		FSCTL_VALIDATE_NEGOTIATE_INFO, true /* is_fsctl */,
-		(char *)&vneg_inbuf, sizeof(struct validate_negotiate_info_req),
+		(char *)pneg_inbuf, sizeof(struct validate_negotiate_info_req),
 		(char **)&pneg_rsp, &rsplen);
 
-	if (rc != 0) {
-		cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", rc);
-		return -EIO;
+	if (ret != 0) {
+		cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", ret);
+		goto out_free_inbuf;
 	}
 
 	if (rsplen != sizeof(struct validate_negotiate_info_rsp)) {
@@ -820,7 +823,7 @@  int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
 		/* relax check since Mac returns max bufsize allowed on ioctl */
 		if ((rsplen > CIFSMaxBufSize)
 		     || (rsplen < sizeof(struct validate_negotiate_info_rsp)))
-			goto err_rsp_free;
+			goto out_free_rsp;
 	}
 
 	/* check validate negotiate info response matches what we got earlier */
@@ -838,14 +841,16 @@  int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
 
 	/* validate negotiate successful */
 	cifs_dbg(FYI, "validate negotiate info successful\n");
-	kfree(pneg_rsp);
-	return 0;
+	rc = 0;
+	goto out_free_rsp;
 
 vneg_out:
 	cifs_dbg(VFS, "protocol revalidation - security settings mismatch\n");
-err_rsp_free:
+out_free_rsp:
 	kfree(pneg_rsp);
-	return -EIO;
+out_free_inbuf:
+	kfree(pneg_inbuf);
+	return rc;
 }
 
 enum securityEnum