Patchwork SCSI Improved checking for LBA out of range

login
register
mail settings
Submitter ronniesahlberg@gmail.com
Date July 12, 2012, 7:05 a.m.
Message ID <1342076712-27013-2-git-send-email-ronniesahlberg@gmail.com>
Download mbox | patch
Permalink /patch/170585/
State New
Headers show

Comments

ronniesahlberg@gmail.com - July 12, 2012, 7:05 a.m.
Improve the tests for the LBA to cover more cases, the new test looks like this
        if (r->req.cmd.lba > r->req.cmd.lba + len
        ||  r->req.cmd.lba + len > s->qdev.max_lba + 1) {

For the 16 byte opcodes, the lba is a uint64, so the first check is to make sure that we do not wrap.
For example if an opcode would specify the LBA:0xffffffffffffffff and LEN:2
then lba+len would wrap to 1.

The second part of the test is to verify that ALL requested blocks are available, not just the first one.

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
---
 hw/scsi-disk.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

Patch

diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index b2f3c0c..2c2be33 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -1558,7 +1558,8 @@  static int32_t scsi_send_command(SCSIRequest *req, uint8_t *buf)
         if (r->req.cmd.buf[1] & 0xe0) {
             goto fail;
         }
-        if (r->req.cmd.lba > s->qdev.max_lba) {
+        if (r->req.cmd.lba > r->req.cmd.lba + len
+        ||  r->req.cmd.lba + len > s->qdev.max_lba + 1) {
             goto illegal_lba;
         }
         r->sector = r->req.cmd.lba * (s->qdev.blocksize / 512);
@@ -1581,7 +1582,8 @@  static int32_t scsi_send_command(SCSIRequest *req, uint8_t *buf)
         if (r->req.cmd.buf[1] & 0xe0) {
             goto fail;
         }
-        if (r->req.cmd.lba > s->qdev.max_lba) {
+        if (r->req.cmd.lba > r->req.cmd.lba + len
+        ||  r->req.cmd.lba + len > s->qdev.max_lba + 1) {
             goto illegal_lba;
         }
         r->sector = r->req.cmd.lba * (s->qdev.blocksize / 512);