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

[Long Li]

> Subject: RE: [Patch v2 2/6] cifs: Allocate validate negotiation request through
> kmalloc
> 
> 
> 
> > -----Original Message-----
> > From: linux-rdma-owner at vger.kernel.org [mailto:linux-rdma-
> > owner at vger.kernel.org] On Behalf Of Long Li
> > Sent: Tuesday, April 17, 2018 2:17 PM
> > To: Steve French <sfrench at samba.org>; linux-cifs at vger.kernel.org;
> > samba- technical at lists.samba.org; linux-kernel at vger.kernel.org; linux-
> > rdma at vger.kernel.org
> > Cc: longli <longli at microsoft.com>; stable at vger.kernel.org
> > Subject: [Patch v2 2/6] cifs: Allocate validate negotiation request
> > through kmalloc
> >
> > From: Long Li <longli at 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 at mellanox.com>)
> >
> > Fixed typo in the patch title.
> >
> > Signed-off-by: Long Li <longli at microsoft.com>
> > Cc: stable at 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))