target: fix truncation of mode data, support zero allocation length
The offset was not bumped back to the full size after writing the
header of the MODE SENSE response, so the last 1 or 2 bytes were
not copied.
On top of this, support zero-length requests by checking for the
return value of transport_kmap_data_sg.
Testcase: sg_raw -r20 /dev/sdb 5a 00 0a 00 00 00 00 00 14 00
last byte should be 0x1e
it is 0x00 without the patch
it is correct with the patch
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c
index b3d8fd2..9229bd9 100644
--- a/drivers/target/target_core_spc.c
+++ b/drivers/target/target_core_spc.c
@@ -784,7 +784,7 @@
unsigned char *rbuf;
int type = dev->transport->get_device_type(dev);
int ten = (cmd->t_task_cdb[0] == MODE_SENSE_10);
- int offset = ten ? 8 : 4;
+ u32 offset = ten ? 8 : 4;
int length = 0;
unsigned char buf[SE_MODE_PAGE_BUF];
@@ -817,6 +817,7 @@
offset -= 2;
buf[0] = (offset >> 8) & 0xff;
buf[1] = offset & 0xff;
+ offset += 2;
if ((cmd->se_lun->lun_access & TRANSPORT_LUNFLAGS_READ_ONLY) ||
(cmd->se_deve &&
@@ -826,13 +827,10 @@
if ((dev->se_sub_dev->se_dev_attrib.emulate_write_cache > 0) &&
(dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0))
spc_modesense_dpofua(&buf[3], type);
-
- if ((offset + 2) > cmd->data_length)
- offset = cmd->data_length;
-
} else {
offset -= 1;
buf[0] = offset & 0xff;
+ offset += 1;
if ((cmd->se_lun->lun_access & TRANSPORT_LUNFLAGS_READ_ONLY) ||
(cmd->se_deve &&
@@ -842,14 +840,13 @@
if ((dev->se_sub_dev->se_dev_attrib.emulate_write_cache > 0) &&
(dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0))
spc_modesense_dpofua(&buf[2], type);
-
- if ((offset + 1) > cmd->data_length)
- offset = cmd->data_length;
}
rbuf = transport_kmap_data_sg(cmd);
- memcpy(rbuf, buf, offset);
- transport_kunmap_data_sg(cmd);
+ if (rbuf) {
+ memcpy(rbuf, buf, min(offset, cmd->data_length));
+ transport_kunmap_data_sg(cmd);
+ }
target_complete_cmd(cmd, GOOD);
return 0;