3.16.60-rc1 review patch. If anyone has any objections, please let me know.
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From: Long Li longli@microsoft.com
commit 2796d303e3c5ec213c578ed3a66872205c126eb8 upstream.
The data buffer allocated on the stack can't be DMA'ed, ib_dma_map_page will return an invalid DMA address for a buffer on stack. Even worse, this incorrect address can't be detected by ib_dma_mapping_error. Sending data from this address to hardware will not fail, but the remote peer will get junk data.
Fix this by allocating the request on the heap in smb3_validate_negotiate.
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.
Changes in v3: Added "Fixes" to the patch. Changed several sizeof() to use *pointer in place of struct.
Changes in v4: Added detailed comments on the failure through RDMA. Allocate request buffer using GPF_NOFS. Fixed possible memory leak.
Changes in v5: Removed variable ret for checking return value. Changed to use pneg_inbuf->Dialects[0] to calculate unused space in pneg_inbuf.
Fixes: ff1c038addc4 ("Check SMB3 dialects against downgrade attacks") Signed-off-by: Long Li longli@microsoft.com Signed-off-by: Steve French stfrench@microsoft.com Reviewed-by: Ronnie Sahlberg lsahlber@redhat.com Reviewed-by: Tom Talpey ttalpey@microsoft.com [bwh: Backported to 3.16: We only ever pass one dialect] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- fs/cifs/smb2pdu.c | 68 ++++++++++++++++++++++++++--------------------- 1 file changed, 38 insertions(+), 30 deletions(-)
--- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -477,8 +477,8 @@ neg_exit:
int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon) { - int rc = 0; - struct validate_negotiate_info_req vneg_inbuf; + int rc; + struct validate_negotiate_info_req *pneg_inbuf; struct validate_negotiate_info_rsp *pneg_rsp = NULL; u32 rsplen;
@@ -502,42 +502,47 @@ int smb3_validate_negotiate(const unsign 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 = kmalloc(sizeof(*pneg_inbuf), GFP_NOFS); + if (!pneg_inbuf) + return -ENOMEM; + + 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;
- vneg_inbuf.DialectCount = cpu_to_le16(1); - vneg_inbuf.Dialects[0] = + pneg_inbuf->DialectCount = cpu_to_le16(1); + pneg_inbuf->Dialects[0] = cpu_to_le16(tcon->ses->server->vals->protocol_id);
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); - return -EIO; + rc = -EIO; + goto out_free_inbuf; }
- if (rsplen != sizeof(struct validate_negotiate_info_rsp)) { + rc = -EIO; + if (rsplen != sizeof(*pneg_rsp)) { cifs_dbg(VFS, "invalid protocol negotiate response size: %d\n", rsplen);
/* relax check since Mac returns max bufsize allowed on ioctl */ - if ((rsplen > CIFSMaxBufSize) - || (rsplen < sizeof(struct validate_negotiate_info_rsp))) - goto err_rsp_free; + if (rsplen > CIFSMaxBufSize || rsplen < sizeof(*pneg_rsp)) + goto out_free_rsp; }
/* check validate negotiate info response matches what we got earlier */ @@ -554,15 +559,17 @@ int smb3_validate_negotiate(const unsign goto vneg_out;
/* validate negotiate successful */ + rc = 0; cifs_dbg(FYI, "validate negotiate info successful\n"); - kfree(pneg_rsp); - return 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; }
int