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| author | Philippe Mathieu-Daudé <f4bug@amsat.org> | 2020-07-17 17:17:05 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-11-03 09:42:53 -0500 |
| commit | 4177b062fc58dd250667415e487618ac59393d04 (patch) | |
| tree | 77bf6c1939e47d16e7171ee68cddc9266c983b7b /hw | |
| parent | f8b8f3746327d577cdd25d6f86bd993178aece58 (diff) | |
| download | qemu-4177b062fc58dd250667415e487618ac59393d04.zip qemu-4177b062fc58dd250667415e487618ac59393d04.tar.gz qemu-4177b062fc58dd250667415e487618ac59393d04.tar.bz2 | |
hw/isa/lpc_ich9: Ignore reserved/invalid SCI IRQ
libFuzzer triggered the following assertion:
cat << EOF | qemu-system-i386 -M pc-q35-5.0 \
-nographic -monitor none -serial none \
-qtest stdio -d guest_errors -trace pci\*
outl 0xcf8 0x8400f841
outl 0xcfc 0xebed205d
outl 0x5d02 0xedf82049
EOF
pci_cfg_write ICH9-LPC 31:0 @0x41 <- 0xebed205d
hw/pci/pci.c:268: int pci_bus_get_irq_level(PCIBus *, int): Assertion `irq_num < bus->nirq' failed.
This is because ich9_lpc_sci_irq() returns -1 for reserved
(illegal) values, but ich9_lpc_pmbase_sci_update() considers
it valid and store it in a 8-bit unsigned type. Then the 255
value is used as GSI IRQ, resulting in a PIRQ value of 247,
more than ICH9_LPC_NB_PIRQS (8).
Fix by simply ignoring the invalid access (and reporting it):
pci_cfg_write ICH9-LPC 31:0 @0x41 <- 0xebed205d
ICH9 LPC: SCI IRQ SEL #3 is reserved
pci_cfg_read mch 00:0 @0x0 -> 0x8086
pci_cfg_read mch 00:0 @0x0 -> 0x29c08086
...
Cc: qemu-stable@nongnu.org
Reported-by: Alexander Bulekov <alxndr@bu.edu>
Fixes: 8f242cb724 ("ich9: implement SCI_IRQ_SEL register")
BugLink: https://bugs.launchpad.net/qemu/+bug/1878642
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20200717151705.18611-1-f4bug@amsat.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'hw')
| -rw-r--r-- | hw/isa/lpc_ich9.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c index 04e5323..087a18d 100644 --- a/hw/isa/lpc_ich9.c +++ b/hw/isa/lpc_ich9.c @@ -29,6 +29,7 @@ */ #include "qemu/osdep.h" +#include "qemu/log.h" #include "cpu.h" #include "qapi/visitor.h" #include "qemu/range.h" @@ -312,10 +313,12 @@ void ich9_generate_smi(void) cpu_interrupt(first_cpu, CPU_INTERRUPT_SMI); } +/* Returns -1 on error, IRQ number on success */ static int ich9_lpc_sci_irq(ICH9LPCState *lpc) { - switch (lpc->d.config[ICH9_LPC_ACPI_CTRL] & - ICH9_LPC_ACPI_CTRL_SCI_IRQ_SEL_MASK) { + uint8_t sel = lpc->d.config[ICH9_LPC_ACPI_CTRL] & + ICH9_LPC_ACPI_CTRL_SCI_IRQ_SEL_MASK; + switch (sel) { case ICH9_LPC_ACPI_CTRL_9: return 9; case ICH9_LPC_ACPI_CTRL_10: @@ -328,6 +331,8 @@ static int ich9_lpc_sci_irq(ICH9LPCState *lpc) return 21; default: /* reserved */ + qemu_log_mask(LOG_GUEST_ERROR, + "ICH9 LPC: SCI IRQ SEL #%u is reserved\n", sel); break; } return -1; @@ -459,7 +464,7 @@ ich9_lpc_pmbase_sci_update(ICH9LPCState *lpc) { uint32_t pm_io_base = pci_get_long(lpc->d.config + ICH9_LPC_PMBASE); uint8_t acpi_cntl = pci_get_long(lpc->d.config + ICH9_LPC_ACPI_CTRL); - uint8_t new_gsi; + int new_gsi; if (acpi_cntl & ICH9_LPC_ACPI_CTRL_ACPI_EN) { pm_io_base &= ICH9_LPC_PMBASE_BASE_ADDRESS_MASK; @@ -470,6 +475,9 @@ ich9_lpc_pmbase_sci_update(ICH9LPCState *lpc) ich9_pm_iospace_update(&lpc->pm, pm_io_base); new_gsi = ich9_lpc_sci_irq(lpc); + if (new_gsi == -1) { + return; + } if (lpc->sci_level && new_gsi != lpc->sci_gsi) { qemu_set_irq(lpc->pm.irq, 0); lpc->sci_gsi = new_gsi; |