6.12-stable review patch. If anyone has any objections, please let me know.
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From: Björn Töpel bjorn@rivosinc.com
[ Upstream commit 332fa4a802b16ccb727199da685294f85f9880cb ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- arch/riscv/kvm/vcpu_sbi.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
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; }