On 02/07/2018 10:52, Dima Stepanov wrote:
> Ping.
>
> On Fri, Jun 15, 2018 at 12:11:44PM +0300, Dima Stepanov wrote:
>> The prh_co_entry() routine handles requests. The first part is to read a
>> request by calling the prh_read_request() routine, if:
>> 1. scsi_cdb_xfer(req->cdb) call returns 0, and
>> 2. req->cdb[0] == PERSISTENT_RESERVE_IN, then
>> The resp->result field will be uninitialized. As a result the resp.sz
>> field will be also uninitialized in the prh_co_entry() function.
>> The second part is to send the response by calling the
>> prh_write_response() routine:
>> 1. For the PERSISTENT_RESERVE_IN command, and
>> 2. resp->result == GOOD (previous successful reply or just luck), then
>> There is a probability that the following assert will not be trigered:
>> assert(resp->sz <= req->sz && resp->sz <= sizeof(client->data));
>> As a result some uninitialized response will be sent.
>>
>> The fix is to initialize the response structure to CHECK_CONDITION and 0
>> values before calling the prh_read_request() routine.
The actual bug is that the "if (sz > 0)" should apply only to
PERSISTENT_RESERVE_OUT, and in fact it can be done in do_pr_out.
PERSISTENT_RESERVE_IN with sz == 0 is weird but okay.
This simplifies the code a bit too, because we can handle closing the
file descriptor in prh_co_entry.
Does something like this work for you?
diff --git a/scsi/qemu-pr-helper.c b/scsi/qemu-pr-helper.c
index 0218d65bbf..c89a446a45 100644
--- a/scsi/qemu-pr-helper.c
+++ b/scsi/qemu-pr-helper.c
@@ -455,6 +455,14 @@ static int multipath_pr_out(int fd, const uint8_t *cdb,
uint8_t *sense,
char transportids[PR_HELPER_DATA_SIZE];
int r;
+ if (sz < PR_OUT_FIXED_PARAM_SIZE) {
+ /* Illegal request, Parameter list length error. This isn't fatal;
+ * we have read the data, send an error without closing the socket.
+ */
+ scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM_LEN));
+ return CHECK_CONDITION;
+ }
+
switch (rq_servact) {
case MPATH_PROUT_REG_SA:
case MPATH_PROUT_RES_SA:
@@ -574,6 +582,12 @@ static int do_pr_out(int fd, const uint8_t *cdb, uint8_t
*sense,
const uint8_t *param, int sz)
{
int resp_sz;
+
+ if ((fcntl(fd, F_GETFL) & O_ACCMODE) == O_RDONLY) {
+ scsi_build_sense(sense, SENSE_CODE(INVALID_OPCODE));
+ return CHECK_CONDITION;
+ }
+
#ifdef CONFIG_MPATH
if (is_mpath(fd)) {
return multipath_pr_out(fd, cdb, sense, param, sz);
@@ -690,21 +704,6 @@ static int coroutine_fn prh_read_request(PRHelperClient
*client,
errp) < 0) {
goto out_close;
}
- if ((fcntl(client->fd, F_GETFL) & O_ACCMODE) == O_RDONLY) {
- scsi_build_sense(resp->sense, SENSE_CODE(INVALID_OPCODE));
- sz = 0;
- } else if (sz < PR_OUT_FIXED_PARAM_SIZE) {
- /* Illegal request, Parameter list length error. This isn't fatal;
- * we have read the data, send an error without closing the socket.
- */
- scsi_build_sense(resp->sense, SENSE_CODE(INVALID_PARAM_LEN));
- sz = 0;
- }
- if (sz == 0) {
- resp->result = CHECK_CONDITION;
- close(client->fd);
- client->fd = -1;
- }
}
req->fd = client->fd;
@@ -785,25 +784,23 @@ static void coroutine_fn prh_co_entry(void *opaque)
break;
}
- if (sz > 0) {
- num_active_sockets++;
- if (req.cdb[0] == PERSISTENT_RESERVE_OUT) {
- r = do_pr_out(req.fd, req.cdb, resp.sense,
- client->data, sz);
- resp.sz = 0;
- } else {
- resp.sz = sizeof(client->data);
- r = do_pr_in(req.fd, req.cdb, resp.sense,
- client->data, &resp.sz);
- resp.sz = MIN(resp.sz, sz);
- }
- num_active_sockets--;
- close(req.fd);
- if (r == -1) {
- break;
- }
- resp.result = r;
+ num_active_sockets++;
+ if (req.cdb[0] == PERSISTENT_RESERVE_OUT) {
+ r = do_pr_out(req.fd, req.cdb, resp.sense,
+ client->data, sz);
+ resp.sz = 0;
+ } else {
+ resp.sz = sizeof(client->data);
+ r = do_pr_in(req.fd, req.cdb, resp.sense,
+ client->data, &resp.sz);
+ resp.sz = MIN(resp.sz, sz);
+ }
+ num_active_sockets--;
+ close(req.fd);
+ if (r == -1) {
+ break;
}
+ resp.result = r;
if (prh_write_response(client, &req, &resp, &local_err) < 0) {
break;
