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.
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 sizeof() to use *pointer in place of struct.
Fixes: ff1c038addc4 ("Check SMB3 dialects against downgrade attacks") Signed-off-by: Long Li longli@microsoft.com Cc: stable@vger.kernel.org --- fs/cifs/smb2pdu.c | 59 ++++++++++++++++++++++++++++++------------------------- 1 file changed, 32 insertions(+), 27 deletions(-)
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 0f044c4..5582a02 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) @@ -764,63 +767,63 @@ 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(*pneg_inbuf), (char **)&pneg_rsp, &rsplen);
- if (rc != 0) { - cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", rc); - return -EIO; + if (ret) { + cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", ret); + goto out_free_inbuf; }
- if (rsplen != sizeof(struct validate_negotiate_info_rsp)) { + 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; + 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
Two comments.
On 4/17/2018 8:33 PM, 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.
This comment is confusing. Any registered memory can be DMA'd, need to state the reason for the choice here more clearly.
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 sizeof() to use *pointer in place of struct.
Fixes: ff1c038addc4 ("Check SMB3 dialects against downgrade attacks") Signed-off-by: Long Li longli@microsoft.com Cc: stable@vger.kernel.org
fs/cifs/smb2pdu.c | 59 ++++++++++++++++++++++++++++++------------------------- 1 file changed, 32 insertions(+), 27 deletions(-)
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 0f044c4..5582a02 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;
Why is this a nonblocking allocation? It would seem more robust to use GFP_NOFS here.
Tom.
/* In SMB3.11 preauth integrity supersedes validate negotiate */ if (tcon->ses->server->dialect == SMB311_PROT_ID) @@ -764,63 +767,63 @@ 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);
vneg_inbuf.SecurityMode =
pneg_inbuf->SecurityMode = cpu_to_le16(SMB2_NEGOTIATE_SIGNING_ENABLED);
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);
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);
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);
- 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(*pneg_inbuf),
- if (rc != 0) {
cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", rc);return -EIO;
- if (ret) {
cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", ret);goto out_free_inbuf;
- if (rsplen != sizeof(struct validate_negotiate_info_rsp)) {
- 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;
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
From: Tom Talpey
Sent: 18 April 2018 12:32
...
On 4/17/2018 8:33 PM, 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.
This comment is confusing. Any registered memory can be DMA'd, need to state the reason for the choice here more clearly.
The stack could be allocated with vmalloc(). In which case the pages might not be physically contiguous and there is no (sensible) call to get the physical address required by the dma controller (or other bus master).
David
On 4/18/2018 9:08 AM, David Laight wrote:
From: Tom Talpey
Sent: 18 April 2018 12:32
...
On 4/17/2018 8:33 PM, 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.
This comment is confusing. Any registered memory can be DMA'd, need to state the reason for the choice here more clearly.
The stack could be allocated with vmalloc(). In which case the pages might not be physically contiguous and there is no (sensible) call to get the physical address required by the dma controller (or other bus master).
Memory registration does not requires pages to be physically contiguous. RDMA Regions can and do support very large physical page scatter/gather, and the adapter DMA's them readily. Is this the only reason?
Tom.
Subject: Re: [Patch v3 2/6] cifs: Allocate validate negotiation request through kmalloc
On 4/18/2018 9:08 AM, David Laight wrote:
From: Tom Talpey
Sent: 18 April 2018 12:32
...
On 4/17/2018 8:33 PM, 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.
This comment is confusing. Any registered memory can be DMA'd, need to state the reason for the choice here more clearly.
The stack could be allocated with vmalloc(). In which case the pages might not be physically contiguous and there is no (sensible) call to get the physical address required by the dma controller (or other bus master).
Memory registration does not requires pages to be physically contiguous. RDMA Regions can and do support very large physical page scatter/gather, and the adapter DMA's them readily. Is this the only reason?
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.
I think it makes sense as stack is dynamic and can shrink as I/O proceeds, so the buffer is gone. Other kernel code use only data on the heap for DMA, e.g. BLK/SCSI layer never use buffer on the stack to send data.
Tom.
On 4/18/2018 1:11 PM, Long Li wrote:
Subject: Re: [Patch v3 2/6] cifs: Allocate validate negotiation request through kmalloc
On 4/18/2018 9:08 AM, David Laight wrote:
From: Tom Talpey
Sent: 18 April 2018 12:32
...
On 4/17/2018 8:33 PM, 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.
This comment is confusing. Any registered memory can be DMA'd, need to state the reason for the choice here more clearly.
The stack could be allocated with vmalloc(). In which case the pages might not be physically contiguous and there is no (sensible) call to get the physical address required by the dma controller (or other bus master).
Memory registration does not requires pages to be physically contiguous. RDMA Regions can and do support very large physical page scatter/gather, and the adapter DMA's them readily. Is this the only reason?
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.
I think it makes sense as stack is dynamic and can shrink as I/O proceeds, so the buffer is gone. Other kernel code use only data on the heap for DMA, e.g. BLK/SCSI layer never use buffer on the stack to send data.
I totally agree that registering the stack is a bad idea. I mainly suggest that you capture these fundamental ib_dma* reasons in the commit. There's no other practical reason why the original approach would not work.
Tom.
Subject: Re: [Patch v3 2/6] cifs: Allocate validate negotiation request through kmalloc
On 4/18/2018 1:11 PM, Long Li wrote:
Subject: Re: [Patch v3 2/6] cifs: Allocate validate negotiation request through kmalloc
On 4/18/2018 9:08 AM, David Laight wrote:
From: Tom Talpey
Sent: 18 April 2018 12:32
...
On 4/17/2018 8:33 PM, 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.
This comment is confusing. Any registered memory can be DMA'd,
need
to state the reason for the choice here more clearly.
The stack could be allocated with vmalloc(). In which case the pages might not be physically contiguous and there is no (sensible) call to get the physical address required by the dma controller (or other bus master).
Memory registration does not requires pages to be physically contiguous. RDMA Regions can and do support very large physical page scatter/gather, and the adapter DMA's them readily. Is this the only
reason?
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.
I think it makes sense as stack is dynamic and can shrink as I/O proceeds, so
the buffer is gone. Other kernel code use only data on the heap for DMA, e.g. BLK/SCSI layer never use buffer on the stack to send data.
I totally agree that registering the stack is a bad idea. I mainly suggest that you capture these fundamental ib_dma* reasons in the commit. There's no other practical reason why the original approach would not work.
Sure I will fix that.
Subject: Re: [Patch v3 2/6] cifs: Allocate validate negotiation request through kmalloc
Two comments.
On 4/17/2018 8:33 PM, 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.
This comment is confusing. Any registered memory can be DMA'd, need to state the reason for the choice here more clearly.
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 sizeof() to use *pointer in place of struct.
Fixes: ff1c038addc4 ("Check SMB3 dialects against downgrade attacks") Signed-off-by: Long Li longli@microsoft.com Cc: stable@vger.kernel.org
fs/cifs/smb2pdu.c | 59 ++++++++++++++++++++++++++++++--------------
1 file changed, 32 insertions(+), 27 deletions(-)
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 0f044c4..5582a02 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;Why is this a nonblocking allocation? It would seem more robust to use GFP_NOFS here.
I agree it makes sense to use GFP_NOFS.
The choice here is made consistent with all the rest CIFS code allocating protocol request buffers. Maybe we should do another patch to cleanup all those code.
Tom.
/* In SMB3.11 preauth integrity supersedes validate negotiate */ if (tcon->ses->server->dialect == SMB311_PROT_ID) @@ -764,63 +767,63 @@ 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);
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);
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);
- 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(structvalidate_negotiate_info_req),
(char *)pneg_inbuf, sizeof(*pneg_inbuf),
- if (rc != 0) {
cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", rc);return -EIO;
- if (ret) {
cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", ret);goto out_free_inbuf;
- if (rsplen != sizeof(struct validate_negotiate_info_rsp)) {
- 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;
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
On 4/18/2018 1:16 PM, Long Li wrote:
Subject: Re: [Patch v3 2/6] cifs: Allocate validate negotiation request through kmalloc
Two comments.
On 4/17/2018 8:33 PM, 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.
This comment is confusing. Any registered memory can be DMA'd, need to state the reason for the choice here more clearly.
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 sizeof() to use *pointer in place of struct.
Fixes: ff1c038addc4 ("Check SMB3 dialects against downgrade attacks") Signed-off-by: Long Li longli@microsoft.com Cc: stable@vger.kernel.org
fs/cifs/smb2pdu.c | 59 ++++++++++++++++++++++++++++++--------------
1 file changed, 32 insertions(+), 27 deletions(-)
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 0f044c4..5582a02 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;Why is this a nonblocking allocation? It would seem more robust to use GFP_NOFS here.
I agree it makes sense to use GFP_NOFS.
The choice here is made consistent with all the rest CIFS code allocating protocol request buffers. Maybe we should do another patch to cleanup all those code.
It'll be required sooner or later. I'm agnostic as to how you apply it, but I still suggest you change this one now rather than continue the fragile behavior. It may not be a global search-and-replace since some allocations may require nonblocking.
Tom.
/* In SMB3.11 preauth integrity supersedes validate negotiate */ if (tcon->ses->server->dialect == SMB311_PROT_ID) @@ -764,63+767,63 @@ 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 flagsent 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;
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);
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(structvalidate_negotiate_info_req),
(char *)pneg_inbuf, sizeof(*pneg_inbuf), (char **)&pneg_rsp, &rsplen);
- if (rc != 0) {
cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", rc);return -EIO;
- if (ret) {
cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", ret);goto out_free_inbuf;
- if (rsplen != sizeof(struct validate_negotiate_info_rsp)) {
- 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;
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
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Subject: Re: [Patch v3 2/6] cifs: Allocate validate negotiation request through kmalloc
On 4/18/2018 1:16 PM, Long Li wrote:
Subject: Re: [Patch v3 2/6] cifs: Allocate validate negotiation request through kmalloc
Two comments.
On 4/17/2018 8:33 PM, 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.
This comment is confusing. Any registered memory can be DMA'd, need to state the reason for the choice here more clearly.
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 sizeof() to use *pointer in place of struct.
Fixes: ff1c038addc4 ("Check SMB3 dialects against downgrade attacks") Signed-off-by: Long Li longli@microsoft.com Cc: stable@vger.kernel.org
fs/cifs/smb2pdu.c | 59 ++++++++++++++++++++++++++++++--------------
1 file changed, 32 insertions(+), 27 deletions(-)
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 0f044c4..5582a02 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;Why is this a nonblocking allocation? It would seem more robust to use GFP_NOFS here.
I agree it makes sense to use GFP_NOFS.
The choice here is made consistent with all the rest CIFS code allocating
protocol request buffers. Maybe we should do another patch to cleanup all those code.
It'll be required sooner or later. I'm agnostic as to how you apply it, but I still suggest you change this one now rather than continue the fragile behavior. It may not be a global search-and-replace since some allocations may require nonblocking.
Okay, I will fix this.
Tom.
/* In SMB3.11 preauth integrity supersedes validate negotiate */ if (tcon->ses->server->dialect == SMB311_PROT_ID) @@ -764,63+767,63 @@ 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 flagsent 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;
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);
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(structvalidate_negotiate_info_req),
(char *)pneg_inbuf, sizeof(*pneg_inbuf), (char **)&pneg_rsp, &rsplen);
- if (rc != 0) {
cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", rc);return -EIO;
- if (ret) {
cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", ret);goto out_free_inbuf;
- if (rsplen != sizeof(struct validate_negotiate_info_rsp)) {
- 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;
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
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linux-stable-mirror@lists.linaro.org
-
David Laight -
Long Li -
Long Li -
Tom Talpey