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| author | Björn Töpel <bjorn@rivosinc.com> | 2024-11-04 20:15:01 +0100 |
|---|---|---|
| committer | Anup Patel <anup@brainfault.org> | 2024-11-05 13:27:32 +0530 |
| commit | 332fa4a802b16ccb727199da685294f85f9880cb (patch) | |
| tree | 8e0fe1c41d7ccd7b8c9e010c44f9016ab7101b9b /arch/riscv | |
| parent | 60821fb4dd7345e5662094accf0a52845306de8c (diff) | |
| download | lwn-332fa4a802b16ccb727199da685294f85f9880cb.tar.gz lwn-332fa4a802b16ccb727199da685294f85f9880cb.zip | |
riscv: kvm: Fix out-of-bounds array access
In kvm_riscv_vcpu_sbi_init() the entry->ext_idx can contain an
out-of-bound index. This is used as a special marker for the base
extensions, that cannot be disabled. However, when traversing the
extensions, that special marker is not checked prior indexing the
array.
Add an out-of-bounds check to the function.
Fixes: 56d8a385b605 ("RISC-V: KVM: Allow some SBI extensions to be disabled by default")
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20241104191503.74725-1-bjorn@kernel.org
Signed-off-by: Anup Patel <anup@brainfault.org>
Diffstat (limited to 'arch/riscv')
| -rw-r--r-- | arch/riscv/kvm/vcpu_sbi.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c index 7de128be8db9..6e704ed86a83 100644 --- a/arch/riscv/kvm/vcpu_sbi.c +++ b/arch/riscv/kvm/vcpu_sbi.c @@ -486,19 +486,22 @@ void kvm_riscv_vcpu_sbi_init(struct kvm_vcpu *vcpu) struct kvm_vcpu_sbi_context *scontext = &vcpu->arch.sbi_context; const struct kvm_riscv_sbi_extension_entry *entry; const struct kvm_vcpu_sbi_extension *ext; - int i; + int idx, i; for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) { entry = &sbi_ext[i]; ext = entry->ext_ptr; + idx = entry->ext_idx; + + if (idx < 0 || idx >= ARRAY_SIZE(scontext->ext_status)) + continue; if (ext->probe && !ext->probe(vcpu)) { - scontext->ext_status[entry->ext_idx] = - KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE; + scontext->ext_status[idx] = KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE; continue; } - scontext->ext_status[entry->ext_idx] = ext->default_disabled ? + scontext->ext_status[idx] = ext->default_disabled ? KVM_RISCV_SBI_EXT_STATUS_DISABLED : KVM_RISCV_SBI_EXT_STATUS_ENABLED; } |