70 lines
2.5 KiB
Diff
70 lines
2.5 KiB
Diff
Fix CVE-2020-1711:
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https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-1711
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Patch copied from upstream source repository:
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https://git.qemu.org/?p=qemu.git;a=commitdiff;h=693fd2acdf14dd86c0bf852610f1c2cca80a74dc
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From 693fd2acdf14dd86c0bf852610f1c2cca80a74dc Mon Sep 17 00:00:00 2001
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From: Felipe Franciosi <felipe@nutanix.com>
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Date: Thu, 23 Jan 2020 12:44:59 +0000
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Subject: [PATCH] iscsi: Cap block count from GET LBA STATUS (CVE-2020-1711)
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When querying an iSCSI server for the provisioning status of blocks (via
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GET LBA STATUS), Qemu only validates that the response descriptor zero's
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LBA matches the one requested. Given the SCSI spec allows servers to
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respond with the status of blocks beyond the end of the LUN, Qemu may
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have its heap corrupted by clearing/setting too many bits at the end of
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its allocmap for the LUN.
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A malicious guest in control of the iSCSI server could carefully program
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Qemu's heap (by selectively setting the bitmap) and then smash it.
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This limits the number of bits that iscsi_co_block_status() will try to
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update in the allocmap so it can't overflow the bitmap.
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Fixes: CVE-2020-1711
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Cc: qemu-stable@nongnu.org
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Signed-off-by: Felipe Franciosi <felipe@nutanix.com>
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Signed-off-by: Peter Turschmid <peter.turschm@nutanix.com>
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Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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---
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block/iscsi.c | 5 +++--
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1 file changed, 3 insertions(+), 2 deletions(-)
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diff --git a/block/iscsi.c b/block/iscsi.c
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index 2aea7e3f13..cbd57294ab 100644
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--- a/block/iscsi.c
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+++ b/block/iscsi.c
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@@ -701,7 +701,7 @@ static int coroutine_fn iscsi_co_block_status(BlockDriverState *bs,
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struct scsi_get_lba_status *lbas = NULL;
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struct scsi_lba_status_descriptor *lbasd = NULL;
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struct IscsiTask iTask;
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- uint64_t lba;
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+ uint64_t lba, max_bytes;
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int ret;
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iscsi_co_init_iscsitask(iscsilun, &iTask);
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@@ -721,6 +721,7 @@ static int coroutine_fn iscsi_co_block_status(BlockDriverState *bs,
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}
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lba = offset / iscsilun->block_size;
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+ max_bytes = (iscsilun->num_blocks - lba) * iscsilun->block_size;
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qemu_mutex_lock(&iscsilun->mutex);
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retry:
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@@ -764,7 +765,7 @@ retry:
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goto out_unlock;
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}
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- *pnum = (int64_t) lbasd->num_blocks * iscsilun->block_size;
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+ *pnum = MIN((int64_t) lbasd->num_blocks * iscsilun->block_size, max_bytes);
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if (lbasd->provisioning == SCSI_PROVISIONING_TYPE_DEALLOCATED ||
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lbasd->provisioning == SCSI_PROVISIONING_TYPE_ANCHORED) {
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--
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2.25.0
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