[Xen-changelog] [qemu-upstream-unstable] scsi: fix buffer overflow in scsi_req_parse_cdb (CVE-2015-5158)

[patchbot@xxxxxxx]

commit e40ae8730e83e25f160c7576dd32d882bf2a3846
Author:     Paolo Bonzini <pbonzini@xxxxxxxxxx>
AuthorDate: Tue Jul 21 08:59:39 2015 +0200
Commit:     Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
CommitDate: Wed Jul 29 15:20:24 2015 +0000

    scsi: fix buffer overflow in scsi_req_parse_cdb (CVE-2015-5158)

    This is a guest-triggerable buffer overflow present in QEMU 2.2.0
    and newer.  scsi_cdb_length returns -1 as an error value, but the
    caller does not check it.

    Luckily, the massive overflow means that QEMU will just SIGSEGV,
    making the impact much smaller.

    upstream-commit-id: c170aad8b057223b1139d72e5ce7acceafab4fa9

    Reported-by: Zhu Donghai (��海) <donghai.zdh@xxxxxxxxxxxxxxx>
    Fixes: 1894df02811f6b79ea3ffbf1084599d96f316173
    Reviewed-by: Fam Zheng <famz@xxxxxxxxxx>
    Cc: qemu-stable@xxxxxxxxxx
    Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
    Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
 hw/scsi/scsi-bus.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
index 9b740a3..8e4a986 100644
--- a/hw/scsi/scsi-bus.c
+++ b/hw/scsi/scsi-bus.c
@@ -1234,10 +1234,15 @@ int scsi_cdb_length(uint8_t *buf) {
 int scsi_req_parse_cdb(SCSIDevice *dev, SCSICommand *cmd, uint8_t *buf)
 {
     int rc;
+    int len;

     cmd->lba = -1;
-    cmd->len = scsi_cdb_length(buf);
+    len = scsi_cdb_length(buf);
+    if (len < 0) {
+        return -1;
+    }

+    cmd->len = len;
     switch (dev->type) {
     case TYPE_TAPE:
         rc = scsi_req_stream_xfer(cmd, dev, buf);
--
generated by git-patchbot for /home/xen/git/qemu-upstream-unstable.git

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