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megasas: do not read DCMD opcode more than once from frame

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Avoid TOC-TOU bugs by storing the DCMD opcode in the MegasasCmd

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2017-06-01 17:18:23 +02:00
parent 24c0c77af5
commit 5104fac853
1 changed files with 11 additions and 14 deletions
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25
hw/scsi/megasas.c
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@ -63,6 +63,7 @@ typedef struct MegasasCmd {
hwaddr pa;
hwaddr pa_size;
uint32_t dcmd_opcode;
union mfi_frame *frame;
SCSIRequest *req;
QEMUSGList qsg;
@ -513,6 +514,7 @@ static MegasasCmd *megasas_enqueue_frame(MegasasState *s,
cmd->context &= (uint64_t)0xFFFFFFFF;
}
cmd->count = count;
cmd->dcmd_opcode = -1;
s->busy++;
if (s->consumer_pa) {
@ -1562,22 +1564,21 @@ static const struct dcmd_cmd_tbl_t {
static int megasas_handle_dcmd(MegasasState *s, MegasasCmd *cmd)
{
int opcode;
int retval = 0;
size_t len;
const struct dcmd_cmd_tbl_t *cmdptr = dcmd_cmd_tbl;
opcode = le32_to_cpu(cmd->frame->dcmd.opcode);
trace_megasas_handle_dcmd(cmd->index, opcode);
cmd->dcmd_opcode = le32_to_cpu(cmd->frame->dcmd.opcode);
trace_megasas_handle_dcmd(cmd->index, cmd->dcmd_opcode);
if (megasas_map_dcmd(s, cmd) < 0) {
return MFI_STAT_MEMORY_NOT_AVAILABLE;
}
while (cmdptr->opcode != -1 && cmdptr->opcode != opcode) {
while (cmdptr->opcode != -1 && cmdptr->opcode != cmd->dcmd_opcode) {
cmdptr++;
}
len = cmd->iov_size;
if (cmdptr->opcode == -1) {
trace_megasas_dcmd_unhandled(cmd->index, opcode, len);
trace_megasas_dcmd_unhandled(cmd->index, cmd->dcmd_opcode, len);
retval = megasas_dcmd_dummy(s, cmd);
} else {
trace_megasas_dcmd_enter(cmd->index, cmdptr->desc, len);
@ -1592,13 +1593,11 @@ static int megasas_handle_dcmd(MegasasState *s, MegasasCmd *cmd)
static int megasas_finish_internal_dcmd(MegasasCmd *cmd,
SCSIRequest *req)
{
int opcode;
int retval = MFI_STAT_OK;
int lun = req->lun;
opcode = le32_to_cpu(cmd->frame->dcmd.opcode);
trace_megasas_dcmd_internal_finish(cmd->index, opcode, lun);
switch (opcode) {
trace_megasas_dcmd_internal_finish(cmd->index, cmd->dcmd_opcode, lun);
switch (cmd->dcmd_opcode) {
case MFI_DCMD_PD_GET_INFO:
retval = megasas_pd_get_info_submit(req->dev, lun, cmd);
break;
@ -1606,7 +1605,7 @@ static int megasas_finish_internal_dcmd(MegasasCmd *cmd,
retval = megasas_ld_get_info_submit(req->dev, lun, cmd);
break;
default:
trace_megasas_dcmd_internal_invalid(cmd->index, opcode);
trace_megasas_dcmd_internal_invalid(cmd->index, cmd->dcmd_opcode);
retval = MFI_STAT_INVALID_DCMD;
break;
}
@ -1827,7 +1826,6 @@ static void megasas_xfer_complete(SCSIRequest *req, uint32_t len)
{
MegasasCmd *cmd = req->hba_private;
uint8_t *buf;
uint32_t opcode;
trace_megasas_io_complete(cmd->index, len);
@ -1837,8 +1835,7 @@ static void megasas_xfer_complete(SCSIRequest *req, uint32_t len)
}
buf = scsi_req_get_buf(req);
opcode = le32_to_cpu(cmd->frame->dcmd.opcode);
if (opcode == MFI_DCMD_PD_GET_INFO && cmd->iov_buf) {
if (cmd->dcmd_opcode == MFI_DCMD_PD_GET_INFO && cmd->iov_buf) {
struct mfi_pd_info *info = cmd->iov_buf;
if (info->inquiry_data[0] == 0x7f) {
@ -1849,7 +1846,7 @@ static void megasas_xfer_complete(SCSIRequest *req, uint32_t len)
memcpy(info->vpd_page83, buf, len);
}
scsi_req_continue(req);
} else if (opcode == MFI_DCMD_LD_GET_INFO) {
} else if (cmd->dcmd_opcode == MFI_DCMD_LD_GET_INFO) {
struct mfi_ld_info *info = cmd->iov_buf;
if (cmd->iov_buf) {