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| author | Philippe Mathieu-Daudé <f4bug@amsat.org> | 2021-01-31 11:34:01 +0100 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2021-02-02 17:00:55 +0000 |
| commit | edfe2eb4360cde4ed5d95bda7777edcb3510f76a (patch) | |
| tree | 2a5891b4b877ef1ca9a1a7ddf5e471eee7cd7ca4 /hw/intc | |
| parent | 8c495d1379211554208c58be75736e3be5ad60e8 (diff) | |
| download | qemu-edfe2eb4360cde4ed5d95bda7777edcb3510f76a.zip qemu-edfe2eb4360cde4ed5d95bda7777edcb3510f76a.tar.gz qemu-edfe2eb4360cde4ed5d95bda7777edcb3510f76a.tar.bz2 | |
hw/intc/arm_gic: Fix interrupt ID in GICD_SGIR register
Per the ARM Generic Interrupt Controller Architecture specification
(document "ARM IHI 0048B.b (ID072613)"), the SGIINTID field is 4 bit,
not 10:
- 4.3 Distributor register descriptions
- 4.3.15 Software Generated Interrupt Register, GICD_SG
- Table 4-21 GICD_SGIR bit assignments
The Interrupt ID of the SGI to forward to the specified CPU
interfaces. The value of this field is the Interrupt ID, in
the range 0-15, for example a value of 0b0011 specifies
Interrupt ID 3.
Correct the irq mask to fix an undefined behavior (which eventually
lead to a heap-buffer-overflow, see [Buglink]):
$ echo 'writel 0x8000f00 0xff4affb0' | qemu-system-aarch64 -M virt,accel=qtest -qtest stdio
[I 1612088147.116987] OPENED
[R +0.278293] writel 0x8000f00 0xff4affb0
../hw/intc/arm_gic.c:1498:13: runtime error: index 944 out of bounds for type 'uint8_t [16][8]'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../hw/intc/arm_gic.c:1498:13
This fixes a security issue when running with KVM on Arm with
kernel-irqchip=off. (The default is kernel-irqchip=on, which is
unaffected, and which is also the correct choice for performance.)
Cc: qemu-stable@nongnu.org
Fixes: CVE-2021-20221
Fixes: 9ee6e8bb853 ("ARMv7 support.")
Buglink: https://bugs.launchpad.net/qemu/+bug/1913916
Buglink: https://bugs.launchpad.net/qemu/+bug/1913917
Reported-by: Alexander Bulekov <alxndr@bu.edu>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20210131103401.217160-1-f4bug@amsat.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'hw/intc')
| -rw-r--r-- | hw/intc/arm_gic.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c index c33b1c8..a994b1f 100644 --- a/hw/intc/arm_gic.c +++ b/hw/intc/arm_gic.c @@ -1477,7 +1477,7 @@ static void gic_dist_writel(void *opaque, hwaddr offset, int target_cpu; cpu = gic_get_current_cpu(s); - irq = value & 0x3ff; + irq = value & 0xf; switch ((value >> 24) & 3) { case 0: mask = (value >> 16) & ALL_CPU_MASK; |