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cifs: consolidate SendReceive response checks
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Further consolidate the SendReceive code by moving the checks run over
the packet into a separate function that all the SendReceive variants
can call.

We can also eliminate the check for a receive_len that's too big or too
small. cifs_demultiplex_thread already checks that and disconnects the
socket if that occurs, while setting the midStatus to MALFORMED. It'll
never call this code if that's the case.

Finally do a little cleanup. Use "goto out" on errors so that the flow
of code in the normal case is more evident. Also switch the logErr
variable in map_smb_to_linux_error to a bool.

Reviewed-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
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Jeff Layton authored and Steve French committed May 23, 2011
1 parent 71a8638 commit 2c8f981
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Showing 3 changed files with 45 additions and 118 deletions.
4 changes: 3 additions & 1 deletion fs/cifs/cifsproto.h
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Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,8 @@ extern int SendReceive(const unsigned int /* xid */ , struct cifsSesInfo *,
int * /* bytes returned */ , const int long_op);
extern int SendReceiveNoRsp(const unsigned int xid, struct cifsSesInfo *ses,
struct smb_hdr *in_buf, int flags);
extern int cifs_check_receive(struct mid_q_entry *mid,
struct TCP_Server_Info *server, bool log_error);
extern int SendReceive2(const unsigned int /* xid */ , struct cifsSesInfo *,
struct kvec *, int /* nvec to send */,
int * /* type of buf returned */ , const int flags);
Expand All @@ -99,7 +101,7 @@ extern int cifs_convert_address(struct sockaddr *dst, const char *src, int len);
extern int cifs_set_port(struct sockaddr *addr, const unsigned short int port);
extern int cifs_fill_sockaddr(struct sockaddr *dst, const char *src, int len,
const unsigned short int port);
extern int map_smb_to_linux_error(struct smb_hdr *smb, int logErr);
extern int map_smb_to_linux_error(struct smb_hdr *smb, bool logErr);
extern void header_assemble(struct smb_hdr *, char /* command */ ,
const struct cifsTconInfo *, int /* length of
fixed section (word count) in two byte units */);
Expand Down
2 changes: 1 addition & 1 deletion fs/cifs/netmisc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -836,7 +836,7 @@ ntstatus_to_dos(__u32 ntstatus, __u8 *eclass, __u16 *ecode)
}

int
map_smb_to_linux_error(struct smb_hdr *smb, int logErr)
map_smb_to_linux_error(struct smb_hdr *smb, bool logErr)
{
unsigned int i;
int rc = -EIO; /* if transport error smb error may not be set */
Expand Down
157 changes: 41 additions & 116 deletions fs/cifs/transport.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -501,14 +501,32 @@ send_nt_cancel(struct TCP_Server_Info *server, struct smb_hdr *in_buf,
return rc;
}

int
cifs_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
bool log_error)
{
dump_smb(mid->resp_buf,
min_t(u32, 92, be32_to_cpu(mid->resp_buf->smb_buf_length)));

/* convert the length into a more usable form */
if (server->secMode & (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) {
/* FIXME: add code to kill session */
if (cifs_verify_signature(mid->resp_buf, server,
mid->sequence_number + 1) != 0)
cERROR(1, "Unexpected SMB signature");
}

/* BB special case reconnect tid and uid here? */
return map_smb_to_linux_error(mid->resp_buf, log_error);
}

int
SendReceive2(const unsigned int xid, struct cifsSesInfo *ses,
struct kvec *iov, int n_vec, int *pRespBufType /* ret */,
const int flags)
{
int rc = 0;
int long_op;
unsigned int receive_len;
struct mid_q_entry *midQ;
struct smb_hdr *in_buf = iov[0].iov_base;

Expand Down Expand Up @@ -605,54 +623,24 @@ SendReceive2(const unsigned int xid, struct cifsSesInfo *ses,
return rc;
}

receive_len = be32_to_cpu(midQ->resp_buf->smb_buf_length);

if (receive_len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE) {
cERROR(1, "Frame too large received. Length: %d Xid: %d",
receive_len, xid);
if (!midQ->resp_buf || midQ->midState != MID_RESPONSE_RECEIVED) {
rc = -EIO;
cFYI(1, "Bad MID state?");
goto out;
}

/* rcvd frame is ok */

if (midQ->resp_buf &&
(midQ->midState == MID_RESPONSE_RECEIVED)) {

iov[0].iov_base = (char *)midQ->resp_buf;
if (midQ->largeBuf)
*pRespBufType = CIFS_LARGE_BUFFER;
else
*pRespBufType = CIFS_SMALL_BUFFER;
iov[0].iov_len = receive_len + 4;

dump_smb(midQ->resp_buf, 80);
/* convert the length into a more usable form */
if ((receive_len > 24) &&
(ses->server->secMode & (SECMODE_SIGN_REQUIRED |
SECMODE_SIGN_ENABLED))) {
rc = cifs_verify_signature(midQ->resp_buf,
ses->server,
midQ->sequence_number+1);
if (rc) {
cERROR(1, "Unexpected SMB signature");
/* BB FIXME add code to kill session */
}
}

/* BB special case reconnect tid and uid here? */
rc = map_smb_to_linux_error(midQ->resp_buf,
flags & CIFS_LOG_ERROR);
iov[0].iov_base = (char *)midQ->resp_buf;
iov[0].iov_len = be32_to_cpu(midQ->resp_buf->smb_buf_length) + 4;
if (midQ->largeBuf)
*pRespBufType = CIFS_LARGE_BUFFER;
else
*pRespBufType = CIFS_SMALL_BUFFER;

if ((flags & CIFS_NO_RESP) == 0)
midQ->resp_buf = NULL; /* mark it so buf will
not be freed by
delete_mid */
} else {
rc = -EIO;
cFYI(1, "Bad MID state?");
}
rc = cifs_check_receive(midQ, ses->server, flags & CIFS_LOG_ERROR);

/* mark it so buf will not be freed by delete_mid */
if ((flags & CIFS_NO_RESP) == 0)
midQ->resp_buf = NULL;
out:
delete_mid(midQ);
atomic_dec(&ses->server->inFlight);
Expand All @@ -667,7 +655,6 @@ SendReceive(const unsigned int xid, struct cifsSesInfo *ses,
int *pbytes_returned, const int long_op)
{
int rc = 0;
unsigned int receive_len;
struct mid_q_entry *midQ;

if (ses == NULL) {
Expand Down Expand Up @@ -757,47 +744,16 @@ SendReceive(const unsigned int xid, struct cifsSesInfo *ses,
return rc;
}

receive_len = be32_to_cpu(midQ->resp_buf->smb_buf_length);

if (receive_len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE) {
cERROR(1, "Frame too large received. Length: %d Xid: %d",
receive_len, xid);
rc = -EIO;
goto out;
}

/* rcvd frame is ok */

if (midQ->resp_buf && out_buf
&& (midQ->midState == MID_RESPONSE_RECEIVED)) {
out_buf->smb_buf_length = cpu_to_be32(receive_len);
memcpy((char *)out_buf + 4,
(char *)midQ->resp_buf + 4,
receive_len);

dump_smb(out_buf, 92);
/* convert the length into a more usable form */
if ((receive_len > 24) &&
(ses->server->secMode & (SECMODE_SIGN_REQUIRED |
SECMODE_SIGN_ENABLED))) {
rc = cifs_verify_signature(out_buf,
ses->server,
midQ->sequence_number+1);
if (rc) {
cERROR(1, "Unexpected SMB signature");
/* BB FIXME add code to kill session */
}
}

*pbytes_returned = be32_to_cpu(out_buf->smb_buf_length);

/* BB special case reconnect tid and uid here? */
rc = map_smb_to_linux_error(out_buf, 0 /* no log */ );
} else {
if (!midQ->resp_buf || !out_buf ||
midQ->midState != MID_RESPONSE_RECEIVED) {
rc = -EIO;
cERROR(1, "Bad MID state?");
goto out;
}

*pbytes_returned = be32_to_cpu(midQ->resp_buf->smb_buf_length);
memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
rc = cifs_check_receive(midQ, ses->server, 0);
out:
delete_mid(midQ);
atomic_dec(&ses->server->inFlight);
Expand Down Expand Up @@ -838,7 +794,6 @@ SendReceiveBlockingLock(const unsigned int xid, struct cifsTconInfo *tcon,
{
int rc = 0;
int rstart = 0;
unsigned int receive_len;
struct mid_q_entry *midQ;
struct cifsSesInfo *ses;

Expand Down Expand Up @@ -961,46 +916,16 @@ SendReceiveBlockingLock(const unsigned int xid, struct cifsTconInfo *tcon,
if (rc != 0)
return rc;

receive_len = be32_to_cpu(midQ->resp_buf->smb_buf_length);
if (receive_len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE) {
cERROR(1, "Frame too large received. Length: %d Xid: %d",
receive_len, xid);
rc = -EIO;
goto out;
}

/* rcvd frame is ok */

if ((out_buf == NULL) || (midQ->midState != MID_RESPONSE_RECEIVED)) {
if (out_buf == NULL || midQ->midState != MID_RESPONSE_RECEIVED) {
rc = -EIO;
cERROR(1, "Bad MID state?");
goto out;
}

out_buf->smb_buf_length = cpu_to_be32(receive_len);
memcpy((char *)out_buf + 4,
(char *)midQ->resp_buf + 4,
receive_len);

dump_smb(out_buf, 92);
/* convert the length into a more usable form */
if ((receive_len > 24) &&
(ses->server->secMode & (SECMODE_SIGN_REQUIRED |
SECMODE_SIGN_ENABLED))) {
rc = cifs_verify_signature(out_buf,
ses->server,
midQ->sequence_number+1);
if (rc) {
cERROR(1, "Unexpected SMB signature");
/* BB FIXME add code to kill session */
}
}

*pbytes_returned = be32_to_cpu(out_buf->smb_buf_length);

/* BB special case reconnect tid and uid here? */
rc = map_smb_to_linux_error(out_buf, 0 /* no log */ );

*pbytes_returned = be32_to_cpu(midQ->resp_buf->smb_buf_length);
memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
rc = cifs_check_receive(midQ, ses->server, 0);
out:
delete_mid(midQ);
if (rstart && rc == -EACCES)
Expand Down

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