diff options
author | Peter Maydell <peter.maydell@linaro.org> | 2018-07-16 17:18:41 +0100 |
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committer | Peter Maydell <peter.maydell@linaro.org> | 2018-07-16 17:18:41 +0100 |
commit | ee03cca88ec2e4cd1ffd319764cced1cab707ee2 (patch) | |
tree | e90014334432f9f0e1ea5a1a82be1058cd710d8e /hw/intc | |
parent | 333b9c8a684c58f6711521e446e4b26de5addadc (diff) |
hw/intc/arm_gic: Check interrupt number in gic_deactivate_irq()
In gic_deactivate_irq() the interrupt number comes from the guest
(on a write to the GICC_DIR register), so we need to sanity check
that it isn't out of range before we use it as an array index.
Handle this in a similar manner to the check we do in
gic_complete_irq() for the GICC_EOI register.
The array overrun is not disastrous because the calling code
uses (value & 0x3ff) to extract the interrupt field, so the
only out-of-range values possible are 1020..1023, which allow
overrunning only from irq_state[] into the following
irq_target[] array which the guest can already manipulate.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Luc Michel <luc.michel@greensocs.com>
Message-id: 20180712154152.32183-2-peter.maydell@linaro.org
Diffstat (limited to 'hw/intc')
-rw-r--r-- | hw/intc/arm_gic.c | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c index ea0323f969..b0a69d6386 100644 --- a/hw/intc/arm_gic.c +++ b/hw/intc/arm_gic.c @@ -543,7 +543,21 @@ static bool gic_eoi_split(GICState *s, int cpu, MemTxAttrs attrs) static void gic_deactivate_irq(GICState *s, int cpu, int irq, MemTxAttrs attrs) { int cm = 1 << cpu; - int group = gic_has_groups(s) && GIC_TEST_GROUP(irq, cm); + int group; + + if (irq >= s->num_irq) { + /* + * This handles two cases: + * 1. If software writes the ID of a spurious interrupt [ie 1023] + * to the GICC_DIR, the GIC ignores that write. + * 2. If software writes the number of a non-existent interrupt + * this must be a subcase of "value written is not an active interrupt" + * and so this is UNPREDICTABLE. We choose to ignore it. + */ + return; + } + + group = gic_has_groups(s) && GIC_TEST_GROUP(irq, cm); if (!gic_eoi_split(s, cpu, attrs)) { /* This is UNPREDICTABLE; we choose to ignore it */ |