From: Sebastian Ene Date: Fri, 17 Oct 2025 07:57:10 +0000 (+0000) Subject: KVM: arm64: Check the untrusted offset in FF-A memory share X-Git-Tag: v6.18-rc6~42^2~3^2~6 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=103e17aac09cdd358133f9e00998b75d6c1f1518;p=thirdparty%2Flinux.git KVM: arm64: Check the untrusted offset in FF-A memory share Verify the offset to prevent OOB access in the hypervisor FF-A buffer in case an untrusted large enough value [U32_MAX - sizeof(struct ffa_composite_mem_region) + 1, U32_MAX] is set from the host kernel. Signed-off-by: Sebastian Ene Acked-by: Will Deacon Link: https://patch.msgid.link/20251017075710.2605118-1-sebastianene@google.com Signed-off-by: Marc Zyngier --- diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c index 4e16f9b96f63..58b7d0c477d7 100644 --- a/arch/arm64/kvm/hyp/nvhe/ffa.c +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c @@ -479,7 +479,7 @@ static void __do_ffa_mem_xfer(const u64 func_id, struct ffa_mem_region_attributes *ep_mem_access; struct ffa_composite_mem_region *reg; struct ffa_mem_region *buf; - u32 offset, nr_ranges; + u32 offset, nr_ranges, checked_offset; int ret = 0; if (addr_mbz || npages_mbz || fraglen > len || @@ -516,7 +516,12 @@ static void __do_ffa_mem_xfer(const u64 func_id, goto out_unlock; } - if (fraglen < offset + sizeof(struct ffa_composite_mem_region)) { + if (check_add_overflow(offset, sizeof(struct ffa_composite_mem_region), &checked_offset)) { + ret = FFA_RET_INVALID_PARAMETERS; + goto out_unlock; + } + + if (fraglen < checked_offset) { ret = FFA_RET_INVALID_PARAMETERS; goto out_unlock; }