Re: [PATCH 2/6] cifs: Allocate validate negoation request through kmalloc

On Mon, Apr 16, 2018 at 05:49:14PM -0700, Long Li wrote:

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.

Signed-off-by: Long Li longli@microsoft.com

fs/cifs/smb2pdu.c | 38 ++++++++++++++++++++++---------------- 1 file changed, 22 insertions(+), 16 deletions(-)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 0f044c4..abbefe2 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -730,7 +730,7 @@ 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;

• 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) @@ -764,52 +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, 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);

• kfree(pneg_inbuf);
  

  return -EIO; }

@@ -838,12 +842,14 @@ 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_inbuf); kfree(pneg_rsp); return 0;

vneg_out: cifs_dbg(VFS, "protocol revalidation - security settings mismatch\n"); err_rsp_free:

• kfree(pneg_inbuf); kfree(pneg_rsp); return -EIO;

}

2.7.4

<formletter>

This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for how to do this properly.

</formletter>