qemu-kvm/kvm-memory-stricter-checks-prior-to-unsetting-engaged_in.patch
Jon Maloy fc2ddd6b1c * Thu Jun 29 2023 Jon Maloy <jmaloy@redhat.com> - 6.2.0-36
- kvm-memory-prevent-dma-reentracy-issues.patch [bz#1999236]
- kvm-async-Add-an-optional-reentrancy-guard-to-the-BH-API.patch [bz#1999236]
- kvm-checkpatch-add-qemu_bh_new-aio_bh_new-checks.patch [bz#1999236]
- kvm-hw-replace-most-qemu_bh_new-calls-with-qemu_bh_new_g.patch [bz#1999236]
- kvm-lsi53c895a-disable-reentrancy-detection-for-script-R.patch [bz#1999236]
- kvm-bcm2835_property-disable-reentrancy-detection-for-io.patch [bz#1999236]
- kvm-raven-disable-reentrancy-detection-for-iomem.patch [bz#1999236]
- kvm-apic-disable-reentrancy-detection-for-apic-msi.patch [bz#1999236]
- kvm-async-avoid-use-after-free-on-re-entrancy-guard.patch [bz#1999236]
- kvm-memory-stricter-checks-prior-to-unsetting-engaged_in.patch [bz#1999236]
- kvm-lsi53c895a-disable-reentrancy-detection-for-MMIO-reg.patch [bz#1999236]
- kvm-hw-scsi-lsi53c895a-Fix-reentrancy-issues-in-the-LSI-.patch [bz#1999236]
- kvm-target-i386-add-support-for-FLUSH_L1D-feature.patch [bz#2216203]
- kvm-target-i386-add-support-for-FB_CLEAR-feature.patch [bz#2216203]
- kvm-migration-Disable-postcopy-multifd-migration.patch [bz#2169733]
- Resolves: bz#1999236
  (CVE-2021-3750 virt:rhel/qemu-kvm: QEMU: hcd-ehci: DMA reentrancy issue leads to use-after-free [rhel-8])
- Resolves: bz#2216203
  ([qemu-kvm]VM reports vulnerabilty to mmio_stale_data on patched host with microcode)
- Resolves: bz#2169733
  (Qemu on destination host crashed if migrate with postcopy and multifd enabled)
2023-06-29 21:05:35 +00:00

69 lines
2.3 KiB
Diff

From c24e38eb508b3fb42ce3ea62fe8de0be6a95a6a8 Mon Sep 17 00:00:00 2001
From: Jon Maloy <jmaloy@redhat.com>
Date: Wed, 7 Jun 2023 11:45:09 -0400
Subject: [PATCH 10/15] memory: stricter checks prior to unsetting
engaged_in_io
RH-Author: Jon Maloy <jmaloy@redhat.com>
RH-MergeRequest: 277: memory: prevent dma-reentracy issues
RH-Bugzilla: 1999236
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Commit: [10/12] 773b62a84b2bd4f5ee7fb8e1cfb3bb91c3a01de1 (redhat/rhel/src/qemu-kvm/jons-qemu-kvm-2)
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1999236
Upstream: Merged
CVE: CVE-2021-3750
commit 3884bf6468ac6bbb58c2b3feaa74e87f821b52f3
Author: Alexander Bulekov <alxndr@bu.edu>
Date: Tue May 16 04:40:02 2023 -0400
memory: stricter checks prior to unsetting engaged_in_io
engaged_in_io could be unset by an MR with re-entrancy checks disabled.
Ensure that only MRs that can set the engaged_in_io flag can unset it.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20230516084002.3813836-1-alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Jon Maloy <jmaloy@redhat.com>
---
softmmu/memory.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/softmmu/memory.c b/softmmu/memory.c
index 102f0a4248..6b98615357 100644
--- a/softmmu/memory.c
+++ b/softmmu/memory.c
@@ -533,6 +533,7 @@ static MemTxResult access_with_adjusted_size(hwaddr addr,
unsigned access_size;
unsigned i;
MemTxResult r = MEMTX_OK;
+ bool reentrancy_guard_applied = false;
if (!access_size_min) {
access_size_min = 1;
@@ -551,6 +552,7 @@ static MemTxResult access_with_adjusted_size(hwaddr addr,
return MEMTX_ACCESS_ERROR;
}
mr->dev->mem_reentrancy_guard.engaged_in_io = true;
+ reentrancy_guard_applied = true;
}
/* FIXME: support unaligned access? */
@@ -567,7 +569,7 @@ static MemTxResult access_with_adjusted_size(hwaddr addr,
access_mask, attrs);
}
}
- if (mr->dev) {
+ if (mr->dev && reentrancy_guard_applied) {
mr->dev->mem_reentrancy_guard.engaged_in_io = false;
}
return r;
--
2.37.3