qemu: Fix CVE-2020-1711

see https://git.qemu.org/?p=qemu.git;a=commit;h=693fd2acdf14dd86c0bf852610f1c2cca80a74dc

(From OE-Core rev: 66289b3ba800c1b9e74b35fd1af2f4825c698550)

Signed-off-by: Lee Chee Yang <chee.yang.lee@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 66 insertions, 1 deletions

diff --git a/meta/recipes-devtools/qemu/qemu.inc b/meta/recipes-devtools/qemu/qemu.inc
index a557e74e97..f26e722f43 100644
--- a/meta/recipes-devtools/qemu/qemu.inc
+++ b/meta/recipes-devtools/qemu/qemu.inc
@@ -29,7 +29,8 @@ SRC_URI = "https://download.qemu.org/${BPN}-${PV}.tar.xz \
            file://0010-configure-Add-pkg-config-handling-for-libgcrypt.patch \
            file://0011-hw-i386-pc-fix-regression-in-parsing-vga-cmdline-par.patch \
            file://CVE-2019-15890.patch \
-           "
+           file://CVE-2020-1711.patch \
+           "
 UPSTREAM_CHECK_REGEX = "qemu-(?P<pver>\d+(\.\d+)+)\.tar"
 
 SRC_URI[md5sum] = "278eeb294e4b497e79af7a57e660cb9a"
diff --git a/meta/recipes-devtools/qemu/qemu/CVE-2020-1711.patch b/meta/recipes-devtools/qemu/qemu/CVE-2020-1711.patch
new file mode 100644
index 0000000000..aa7bc82329
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu/CVE-2020-1711.patch
@@ -0,0 +1,64 @@
+From 693fd2acdf14dd86c0bf852610f1c2cca80a74dc Mon Sep 17 00:00:00 2001
+From: Felipe Franciosi <felipe@nutanix.com>
+Date: Thu, 23 Jan 2020 12:44:59 +0000
+Subject: [PATCH] iscsi: Cap block count from GET LBA STATUS (CVE-2020-1711)
+
+When querying an iSCSI server for the provisioning status of blocks (via
+GET LBA STATUS), Qemu only validates that the response descriptor zero's
+LBA matches the one requested. Given the SCSI spec allows servers to
+respond with the status of blocks beyond the end of the LUN, Qemu may
+have its heap corrupted by clearing/setting too many bits at the end of
+its allocmap for the LUN.
+
+A malicious guest in control of the iSCSI server could carefully program
+Qemu's heap (by selectively setting the bitmap) and then smash it.
+
+This limits the number of bits that iscsi_co_block_status() will try to
+update in the allocmap so it can't overflow the bitmap.
+
+Upstream-Status: Backport [https://git.qemu.org/?p=qemu.git;a=patch;h=693fd2acdf14dd86c0bf852610f1c2cca80a74dc]
+CVE: CVE-2020-1711
+
+Fixes: CVE-2020-1711
+Cc: qemu-stable@nongnu.org
+Signed-off-by: Felipe Franciosi <felipe@nutanix.com>
+Signed-off-by: Peter Turschmid <peter.turschm@nutanix.com>
+Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
+Signed-off-by: Kevin Wolf <kwolf@redhat.com>
+Signed-off-by: Lee Chee Yang <chee.yang.lee@intel.com>
+---
+ block/iscsi.c | 5 +++--
+ 1 file changed, 3 insertions(+), 2 deletions(-)
+
+diff --git a/block/iscsi.c b/block/iscsi.c
+index 2aea7e3..cbd5729 100644
+--- a/block/iscsi.c
++++ b/block/iscsi.c
+@@ -701,7 +701,7 @@ static int coroutine_fn iscsi_co_block_status(BlockDriverState *bs,
+     struct scsi_get_lba_status *lbas = NULL;
+     struct scsi_lba_status_descriptor *lbasd = NULL;
+     struct IscsiTask iTask;
+-    uint64_t lba;
++    uint64_t lba, max_bytes;
+     int ret;
+ 
+     iscsi_co_init_iscsitask(iscsilun, &iTask);
+@@ -721,6 +721,7 @@ static int coroutine_fn iscsi_co_block_status(BlockDriverState *bs,
+     }
+ 
+     lba = offset / iscsilun->block_size;
++    max_bytes = (iscsilun->num_blocks - lba) * iscsilun->block_size;
+ 
+     qemu_mutex_lock(&iscsilun->mutex);
+ retry:
+@@ -764,7 +765,7 @@ retry:
+         goto out_unlock;
+     }
+ 
+-    *pnum = (int64_t) lbasd->num_blocks * iscsilun->block_size;
++    *pnum = MIN((int64_t) lbasd->num_blocks * iscsilun->block_size, max_bytes);
+ 
+     if (lbasd->provisioning == SCSI_PROVISIONING_TYPE_DEALLOCATED ||
+         lbasd->provisioning == SCSI_PROVISIONING_TYPE_ANCHORED) {
+-- 
+1.8.3.1