linux/drivers/scsi/libfc/fc_elsct.c

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/*
* Copyright(c) 2008 Intel Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
*
* Maintained at www.Open-FCoE.org
*/
/*
* Provide interface to send ELS/CT FC frames
*/
#include <asm/unaligned.h>
#include <scsi/fc/fc_gs.h>
#include <scsi/fc/fc_ns.h>
#include <scsi/fc/fc_els.h>
#include <scsi/libfc.h>
#include <scsi/fc_encode.h>
/**
* fc_elsct_send() - Send an ELS or CT frame
* @lport: The local port to send the frame on
* @did: The destination ID for the frame
* @fp: The frame to be sent
* @op: The operational code
* @resp: The callback routine when the response is received
* @arg: The argument to pass to the response callback routine
* @timer_msec: The timeout period for the frame (in msecs)
*/
struct fc_seq *fc_elsct_send(struct fc_lport *lport, u32 did,
struct fc_frame *fp, unsigned int op,
void (*resp)(struct fc_seq *,
struct fc_frame *,
void *),
void *arg, u32 timer_msec)
{
enum fc_rctl r_ctl;
enum fc_fh_type fh_type;
int rc;
/* ELS requests */
if ((op >= ELS_LS_RJT) && (op <= ELS_AUTH_ELS))
rc = fc_els_fill(lport, did, fp, op, &r_ctl, &fh_type);
else {
/* CT requests */
rc = fc_ct_fill(lport, did, fp, op, &r_ctl, &fh_type);
did = FC_FID_DIR_SERV;
}
[SCSI] libfc: fix memory corruption caused by double frees and bad error handling I was running into several different panics under stress, which I traced down to a few different possible slab corruption issues in error handling paths. I have not yet looked into why these exchange sends fail, but with these fixes my test system is much more stable under stress than before. fc_elsct_send() could fail and either leave the passed in frame intact (failure in fc_ct/els_fill) or the frame could have been freed if the failure was is fc_exch_seq_send(). The caller had no way of knowing, and there was a potential double free in the error handling in fc_fcp_rec(). Make fc_elsct_send() always free the frame before returning, and remove the fc_frame_free() call in fc_fcp_rec(). While fc_exch_seq_send() did always consume the frame, there were double free bugs in the error handling of fc_fcp_cmd_send() and fc_fcp_srr() as well. Numerous calls to error handling routines (fc_disc_error(), fc_lport_error(), fc_rport_error_retry() ) were passing in a frame pointer that had already been freed in the case of an error. I have changed the call sites to pass in a NULL pointer, but there may be more appropriate error codes to use. Question: Why do these error routines take a frame pointer anyway? I understand passing in a pointer encoded error to the response handlers, but the error routines take no action on a valid pointer and should never be called that way. Signed-off-by: Chris Leech <christopher.leech@intel.com> Signed-off-by: Robert Love <robert.w.love@intel.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
2009-10-21 23:28:09 +00:00
if (rc) {
fc_frame_free(fp);
return NULL;
[SCSI] libfc: fix memory corruption caused by double frees and bad error handling I was running into several different panics under stress, which I traced down to a few different possible slab corruption issues in error handling paths. I have not yet looked into why these exchange sends fail, but with these fixes my test system is much more stable under stress than before. fc_elsct_send() could fail and either leave the passed in frame intact (failure in fc_ct/els_fill) or the frame could have been freed if the failure was is fc_exch_seq_send(). The caller had no way of knowing, and there was a potential double free in the error handling in fc_fcp_rec(). Make fc_elsct_send() always free the frame before returning, and remove the fc_frame_free() call in fc_fcp_rec(). While fc_exch_seq_send() did always consume the frame, there were double free bugs in the error handling of fc_fcp_cmd_send() and fc_fcp_srr() as well. Numerous calls to error handling routines (fc_disc_error(), fc_lport_error(), fc_rport_error_retry() ) were passing in a frame pointer that had already been freed in the case of an error. I have changed the call sites to pass in a NULL pointer, but there may be more appropriate error codes to use. Question: Why do these error routines take a frame pointer anyway? I understand passing in a pointer encoded error to the response handlers, but the error routines take no action on a valid pointer and should never be called that way. Signed-off-by: Chris Leech <christopher.leech@intel.com> Signed-off-by: Robert Love <robert.w.love@intel.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
2009-10-21 23:28:09 +00:00
}
fc_fill_fc_hdr(fp, r_ctl, did, lport->port_id, fh_type,
FC_FCTL_REQ, 0);
return lport->tt.exch_seq_send(lport, fp, resp, NULL, arg, timer_msec);
}
EXPORT_SYMBOL(fc_elsct_send);
/**
* fc_elsct_init() - Initialize the ELS/CT layer
* @lport: The local port to initialize the ELS/CT layer for
*/
int fc_elsct_init(struct fc_lport *lport)
{
if (!lport->tt.elsct_send)
lport->tt.elsct_send = fc_elsct_send;
return 0;
}
EXPORT_SYMBOL(fc_elsct_init);
/**
* fc_els_resp_type() - Return a string describing the ELS response
* @fp: The frame pointer or possible error code
*/
const char *fc_els_resp_type(struct fc_frame *fp)
{
const char *msg;
struct fc_frame_header *fh;
struct fc_ct_hdr *ct;
if (IS_ERR(fp)) {
switch (-PTR_ERR(fp)) {
case FC_NO_ERR:
msg = "response no error";
break;
case FC_EX_TIMEOUT:
msg = "response timeout";
break;
case FC_EX_CLOSED:
msg = "response closed";
break;
default:
msg = "response unknown error";
break;
}
} else {
fh = fc_frame_header_get(fp);
switch (fh->fh_type) {
case FC_TYPE_ELS:
switch (fc_frame_payload_op(fp)) {
case ELS_LS_ACC:
msg = "accept";
break;
case ELS_LS_RJT:
msg = "reject";
break;
default:
msg = "response unknown ELS";
break;
}
break;
case FC_TYPE_CT:
ct = fc_frame_payload_get(fp, sizeof(*ct));
if (ct) {
switch (ntohs(ct->ct_cmd)) {
case FC_FS_ACC:
msg = "CT accept";
break;
case FC_FS_RJT:
msg = "CT reject";
break;
default:
msg = "response unknown CT";
break;
}
} else {
msg = "short CT response";
}
break;
default:
msg = "response not ELS or CT";
break;
}
}
return msg;
}