diff options
| author | Alexander Bulekov <alxndr@bu.edu> | 2023-04-27 17:10:06 -0400 |
|---|---|---|
| committer | Michael Tokarev <mjt@tls.msk.ru> | 2023-09-11 10:53:50 +0300 |
| commit | c40ca2301c7603524eaddb5308a3f524c6f89d24 (patch) | |
| tree | 24ea2150b77a79be544e9b52a0af59203890483f /include | |
| parent | 590e71e53679308f822f83ea806f580c29008964 (diff) | |
memory: prevent dma-reentracy issues
Add a flag to the DeviceState, when a device is engaged in PIO/MMIO/DMA.
This flag is set/checked prior to calling a device's MemoryRegion
handlers, and set when device code initiates DMA. The purpose of this
flag is to prevent two types of DMA-based reentrancy issues:
1.) mmio -> dma -> mmio case
2.) bh -> dma write -> mmio case
These issues have led to problems such as stack-exhaustion and
use-after-frees.
Summary of the problem from Peter Maydell:
https://lore.kernel.org/qemu-devel/CAFEAcA_23vc7hE3iaM-JVA6W38LK4hJoWae5KcknhPRD5fPBZA@mail.gmail.com
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/62
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/540
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/541
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/556
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/557
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/827
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1282
Resolves: CVE-2023-0330
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20230427211013.2994127-2-alxndr@bu.edu>
[thuth: Replace warn_report() with warn_report_once()]
Signed-off-by: Thomas Huth <thuth@redhat.com>
(cherry picked from commit a2e1753b8054344f32cf94f31c6399a58794a380)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Diffstat (limited to 'include')
| -rw-r--r-- | include/exec/memory.h | 5 | ||||
| -rw-r--r-- | include/hw/qdev-core.h | 7 |
2 files changed, 12 insertions, 0 deletions
diff --git a/include/exec/memory.h b/include/exec/memory.h index 91f8a2395a..124628ada4 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -741,6 +741,8 @@ struct MemoryRegion { bool is_iommu; RAMBlock *ram_block; Object *owner; + /* owner as TYPE_DEVICE. Used for re-entrancy checks in MR access hotpath */ + DeviceState *dev; const MemoryRegionOps *ops; void *opaque; @@ -765,6 +767,9 @@ struct MemoryRegion { unsigned ioeventfd_nb; MemoryRegionIoeventfd *ioeventfds; RamDiscardManager *rdm; /* Only for RAM */ + + /* For devices designed to perform re-entrant IO into their own IO MRs */ + bool disable_reentrancy_guard; }; struct IOMMUMemoryRegion { diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h index 785dd5a56e..886f6bb79e 100644 --- a/include/hw/qdev-core.h +++ b/include/hw/qdev-core.h @@ -162,6 +162,10 @@ struct NamedClockList { QLIST_ENTRY(NamedClockList) node; }; +typedef struct { + bool engaged_in_io; +} MemReentrancyGuard; + /** * DeviceState: * @realized: Indicates whether the device has been fully constructed. @@ -194,6 +198,9 @@ struct DeviceState { int alias_required_for_version; ResettableState reset; GSList *unplug_blockers; + + /* Is the device currently in mmio/pio/dma? Used to prevent re-entrancy */ + MemReentrancyGuard mem_reentrancy_guard; }; struct DeviceListener { |