From: Björn Töpel Date: Mon, 4 Nov 2024 19:15:01 +0000 (+0100) Subject: riscv: kvm: Fix out-of-bounds array access X-Git-Tag: v6.13-rc1~97^2~16^2 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=332fa4a802b16ccb727199da685294f85f9880cb;p=thirdparty%2Flinux.git 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 Reviewed-by: Anup Patel Link: https://lore.kernel.org/r/20241104191503.74725-1-bjorn@kernel.org Signed-off-by: Anup Patel --- diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c index 7de128be8db9b..6e704ed86a83a 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; }