From: Long Li <[email protected]>
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 <[email protected]>)
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.
Fixes: ff1c038addc4 ("Check SMB3 dialects against downgrade attacks")
Signed-off-by: Long Li <[email protected]>
---
fs/cifs/smb2pdu.c | 61 ++++++++++++++++++++++++++++++-------------------------
1 file changed, 33 insertions(+), 28 deletions(-)
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 0f044c4..caa2a1e 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 */
@@ -741,7 +741,6 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
if (tcon->ses->server->rdma)
return 0;
#endif
-
/* In SMB3.11 preauth integrity supersedes validate negotiate */
if (tcon->ses->server->dialect == SMB311_PROT_ID)
return 0;
@@ -764,63 +763,67 @@ 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 = 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;
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
--
2.7.4
Looks good, but I have two possibly style-related comments.
On 4/19/2018 5:38 PM, Long Li wrote:
> From: Long Li <[email protected]>
>
> 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 <[email protected]>)
> 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.
>
> Fixes: ff1c038addc4 ("Check SMB3 dialects against downgrade attacks")
> Signed-off-by: Long Li <[email protected]>
> ---
> fs/cifs/smb2pdu.c | 61 ++++++++++++++++++++++++++++++-------------------------
> 1 file changed, 33 insertions(+), 28 deletions(-)
>
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index 0f044c4..caa2a1e 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;
Seems awkward to have "rc" and "ret", and based on the code below I
don't see why two variables are needed. Simplify? (see later comment)
> + struct validate_negotiate_info_req *pneg_inbuf;
> struct validate_negotiate_info_rsp *pneg_rsp = NULL;
> u32 rsplen;
> u32 inbuflen; /* max of 4 dialects */
> @@ -741,7 +741,6 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
> if (tcon->ses->server->rdma)
> return 0;
> #endif
> -
> /* In SMB3.11 preauth integrity supersedes validate negotiate */
> if (tcon->ses->server->dialect == SMB311_PROT_ID)
> return 0;
> @@ -764,63 +763,67 @@ 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 = 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;
>
>
> 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;
The "- 2" is a little confusing here. This was existing code, but I
suggest you change this to a sizeof (u16) construct for consistency.
It's reducing by the length of a single Dialects[n] entry.
> } 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;
Ditto previous sizeof (u16) comment, with a *2 this case.
> }
>
> - 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;
> }
Why not leave "rc" alone, and set its value to -EIO before the goto
if the ioctl fails? That will simplify and make the code much more
readable IMO.
>
> - 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;
> }
Would need an rc = -EIO here too if above comment is accepted.
Tom.
>
> /* 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
>
2018-04-20 7:55 GMT-07:00 Tom Talpey <[email protected]>:
> Looks good, but I have two possibly style-related comments.
>
>
> On 4/19/2018 5:38 PM, Long Li wrote:
>>
>> From: Long Li <[email protected]>
>>
>> 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 <[email protected]>)
>> 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.
>>
>> Fixes: ff1c038addc4 ("Check SMB3 dialects against downgrade attacks")
>> Signed-off-by: Long Li <[email protected]>
>> ---
>> fs/cifs/smb2pdu.c | 61
>> ++++++++++++++++++++++++++++++-------------------------
>> 1 file changed, 33 insertions(+), 28 deletions(-)
>>
>> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
>> index 0f044c4..caa2a1e 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;
>
>
> Seems awkward to have "rc" and "ret", and based on the code below I
> don't see why two variables are needed. Simplify? (see later comment)
>
>
>> + struct validate_negotiate_info_req *pneg_inbuf;
>> struct validate_negotiate_info_rsp *pneg_rsp = NULL;
>> u32 rsplen;
>> u32 inbuflen; /* max of 4 dialects */
>> @@ -741,7 +741,6 @@ int smb3_validate_negotiate(const unsigned int xid,
>> struct cifs_tcon *tcon)
>> if (tcon->ses->server->rdma)
>> return 0;
>> #endif
>> -
>> /* In SMB3.11 preauth integrity supersedes validate negotiate */
>> if (tcon->ses->server->dialect == SMB311_PROT_ID)
>> return 0;
>> @@ -764,63 +763,67 @@ 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 = 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;
>> 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;
>
>
> The "- 2" is a little confusing here. This was existing code, but I
> suggest you change this to a sizeof (u16) construct for consistency.
> It's reducing by the length of a single Dialects[n] entry.
I would suggest to make it "- sizeof(pneg_inbuf->Dialects[0])"...
>
>> } 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;
>
>
>
> Ditto previous sizeof (u16) comment, with a *2 this case.
... and "- 2 * sizeof(pneg_inbuf->Dialects[0])" respectively.
>
>> }
>> - 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;
>> }
>
>
> Why not leave "rc" alone, and set its value to -EIO before the goto
> if the ioctl fails? That will simplify and make the code much more
> readable IMO.
>
>> - 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;
>> }
>
>
> Would need an rc = -EIO here too if above comment is accepted.
>
> Tom.
>
>> /* 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
>>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-cifs" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Subject: Re: [Patch v4] cifs: Allocate validate negotiation request through
> kmalloc
>
> Looks good, but I have two possibly style-related comments.
>
> On 4/19/2018 5:38 PM, Long Li wrote:
> > From: Long Li <[email protected]>
> >
> > 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 <[email protected]>) 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.
> >
> > Fixes: ff1c038addc4 ("Check SMB3 dialects against downgrade attacks")
> > Signed-off-by: Long Li <[email protected]>
> > ---
> > fs/cifs/smb2pdu.c | 61 ++++++++++++++++++++++++++++++--------------
> -----------
> > 1 file changed, 33 insertions(+), 28 deletions(-)
> >
> > diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index
> > 0f044c4..caa2a1e 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;
>
> Seems awkward to have "rc" and "ret", and based on the code below I don't
> see why two variables are needed. Simplify? (see later comment)
This is for addressing a prior comment to reduce duplicate code. All the failure paths
(after issuing I/O) returning -EIO, there are 5 of them. Set rc to -EIO at the beginning
so we don’t need to set it multiple times.
>
> > + struct validate_negotiate_info_req *pneg_inbuf;
> > struct validate_negotiate_info_rsp *pneg_rsp = NULL;
> > u32 rsplen;
> > u32 inbuflen; /* max of 4 dialects */ @@ -741,7 +741,6 @@ int
> > smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
> > if (tcon->ses->server->rdma)
> > return 0;
> > #endif
> > -
> > /* In SMB3.11 preauth integrity supersedes validate negotiate */
> > if (tcon->ses->server->dialect == SMB311_PROT_ID)
> > return 0;
> > @@ -764,63 +763,67 @@ 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 = 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;
> >
> >
> > 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;
>
> The "- 2" is a little confusing here. This was existing code, but I suggest you
> change this to a sizeof (u16) construct for consistency.
> It's reducing by the length of a single Dialects[n] entry.
>
> > } 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;
>
> Ditto previous sizeof (u16) comment, with a *2 this case.
>
> > }
> >
> > - 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;
> > }
>
> Why not leave "rc" alone, and set its value to -EIO before the goto if the ioctl
> fails? That will simplify and make the code much more readable IMO.
>
> >
> > - 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;
> > }
>
> Would need an rc = -EIO here too if above comment is accepted.
>
> Tom.
>
> >
> > /* 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 4/20/2018 2:41 PM, Long Li wrote:
>> Subject: Re: [Patch v4] cifs: Allocate validate negotiation request through
>> kmalloc
>>
>> Looks good, but I have two possibly style-related comments.
>>
>> On 4/19/2018 5:38 PM, Long Li wrote:
>>> From: Long Li <[email protected]>
>>>
>>> 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 <[email protected]>) 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.
>>>
>>> Fixes: ff1c038addc4 ("Check SMB3 dialects against downgrade attacks")
>>> Signed-off-by: Long Li <[email protected]>
>>> ---
>>> fs/cifs/smb2pdu.c | 61 ++++++++++++++++++++++++++++++--------------
>> -----------
>>> 1 file changed, 33 insertions(+), 28 deletions(-)
>>>
>>> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index
>>> 0f044c4..caa2a1e 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;
>>
>> Seems awkward to have "rc" and "ret", and based on the code below I don't
>> see why two variables are needed. Simplify? (see later comment)
>
> This is for addressing a prior comment to reduce duplicate code. All the failure paths
> (after issuing I/O) returning -EIO, there are 5 of them. Set rc to -EIO at the beginning
> so we don’t need to set it multiple times.
Well, ok but now there are semi-duplicate and rather confusing "rc"
and "ret" local variables, only one of which is actually returned.
How about a "goto err" with unconditonal -EIO, and just leave the
"return 0" path alone, like it was? That would be much clearer IMO.
As-is, I needed to read it several times to convince myself the right
rc was returned.
Tom,
>
>>
>>> + struct validate_negotiate_info_req *pneg_inbuf;
>>> struct validate_negotiate_info_rsp *pneg_rsp = NULL;
>>> u32 rsplen;
>>> u32 inbuflen; /* max of 4 dialects */ @@ -741,7 +741,6 @@ int
>>> smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
>>> if (tcon->ses->server->rdma)
>>> return 0;
>>> #endif
>>> -
>>> /* In SMB3.11 preauth integrity supersedes validate negotiate */
>>> if (tcon->ses->server->dialect == SMB311_PROT_ID)
>>> return 0;
>>> @@ -764,63 +763,67 @@ 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 = 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;
>>>
>>>
>>> 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;
>>
>> The "- 2" is a little confusing here. This was existing code, but I suggest you
>> change this to a sizeof (u16) construct for consistency.
>> It's reducing by the length of a single Dialects[n] entry.
>>
>>> } 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;
>>
>> Ditto previous sizeof (u16) comment, with a *2 this case.
>>
>>> }
>>>
>>> - 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;
>>> }
>>
>> Why not leave "rc" alone, and set its value to -EIO before the goto if the ioctl
>> fails? That will simplify and make the code much more readable IMO.
>>
>>>
>>> - 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;
>>> }
>>
>> Would need an rc = -EIO here too if above comment is accepted.
>>
>> Tom.
>>
>>>
>>> /* 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 v4] cifs: Allocate validate negotiation request through
> kmalloc
>
> On 4/20/2018 2:41 PM, Long Li wrote:
> >> Subject: Re: [Patch v4] cifs: Allocate validate negotiation request
> >> through kmalloc
> >>
> >> Looks good, but I have two possibly style-related comments.
> >>
> >> On 4/19/2018 5:38 PM, Long Li wrote:
> >>> From: Long Li <[email protected]>
> >>>
> >>> 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 <[email protected]>) 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.
> >>>
> >>> Fixes: ff1c038addc4 ("Check SMB3 dialects against downgrade
> >>> attacks")
> >>> Signed-off-by: Long Li <[email protected]>
> >>> ---
> >>> fs/cifs/smb2pdu.c | 61
> >>> ++++++++++++++++++++++++++++++--------------
> >> -----------
> >>> 1 file changed, 33 insertions(+), 28 deletions(-)
> >>>
> >>> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index
> >>> 0f044c4..caa2a1e 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;
> >>
> >> Seems awkward to have "rc" and "ret", and based on the code below I
> >> don't see why two variables are needed. Simplify? (see later comment)
> >
> > This is for addressing a prior comment to reduce duplicate code. All
> > the failure paths (after issuing I/O) returning -EIO, there are 5 of
> > them. Set rc to -EIO at the beginning so we don’t need to set it multiple
> times.
>
> Well, ok but now there are semi-duplicate and rather confusing "rc"
> and "ret" local variables, only one of which is actually returned.
>
> How about a "goto err" with unconditonal -EIO, and just leave the "return 0"
> path alone, like it was? That would be much clearer IMO.
That means we'll have to call kfree(pneg_rsp) and kfree(pneg_inbuf) on the return 0 path,
as well as the return -EIO path.
I'm happy to do that if there is no objection.
>
> As-is, I needed to read it several times to convince myself the right rc was
> returned.
>
> Tom,
>
>
> >
> >>
> >>> + struct validate_negotiate_info_req *pneg_inbuf;
> >>> struct validate_negotiate_info_rsp *pneg_rsp = NULL;
> >>> u32 rsplen;
> >>> u32 inbuflen; /* max of 4 dialects */ @@ -741,7 +741,6 @@ int
> >>> smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
> >>> if (tcon->ses->server->rdma)
> >>> return 0;
> >>> #endif
> >>> -
> >>> /* In SMB3.11 preauth integrity supersedes validate negotiate */
> >>> if (tcon->ses->server->dialect == SMB311_PROT_ID)
> >>> return 0;
> >>> @@ -764,63 +763,67 @@ 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 = 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;
> >>>
> >>>
> >>> 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;
> >>
> >> The "- 2" is a little confusing here. This was existing code, but I
> >> suggest you change this to a sizeof (u16) construct for consistency.
> >> It's reducing by the length of a single Dialects[n] entry.
> >>
> >>> } 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;
> >>
> >> Ditto previous sizeof (u16) comment, with a *2 this case.
> >>
> >>> }
> >>>
> >>> - 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;
> >>> }
> >>
> >> Why not leave "rc" alone, and set its value to -EIO before the goto
> >> if the ioctl fails? That will simplify and make the code much more readable
> IMO.
> >>
> >>>
> >>> - 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;
> >>> }
> >>
> >> Would need an rc = -EIO here too if above comment is accepted.
> >>
> >> Tom.
> >>
> >>>
> >>> /* 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
> >>>
> > N r y b X ǧv ^ ){.n + { ٚ {ay ʇڙ ,j f h z w
>
> j:+v w j m zZ+ ݢj" !tml=
> >
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