From b470757774a776e2bcbff50c7ae7f40323d10064 Mon Sep 17 00:00:00 2001 Message-Id: From: Michal Privoznik Date: Thu, 7 Mar 2019 14:17:01 +0100 Subject: [PATCH] cpu: Don't access invalid memory in virCPUx86Translate MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Problem is that if there are no signatures for a CPU, then we still allocate cpu->signatures (even though with size 0). Later, we access cpu->signatures[0] if cpu->signatures is not NULL. Invalid read of size 4 at 0x5F439D7: virCPUx86Translate (cpu_x86.c:2930) by 0x5F3C239: virCPUTranslate (cpu.c:927) by 0x57CE7A1: qemuProcessUpdateGuestCPU (qemu_process.c:5870) ... Address 0xf752d40 is 0 bytes after a block of size 0 alloc'd at 0x4C30EC6: calloc (vg_replace_malloc.c:711) by 0x5DBDE4E: virAllocN (viralloc.c:190) by 0x5F3E4FA: x86ModelCopySignatures (cpu_x86.c:990) by 0x5F3E60F: x86ModelCopy (cpu_x86.c:1008) by 0x5F3E7CB: x86ModelFromCPU (cpu_x86.c:1068) by 0x5F4397E: virCPUx86Translate (cpu_x86.c:2922) by 0x5F3C239: virCPUTranslate (cpu.c:927) by 0x57CE7A1: qemuProcessUpdateGuestCPU (qemu_process.c:5870) ... Signed-off-by: Michal Privoznik Reviewed-by: Jiri Denemark (cherry picked from commit 62cb9c335c43a722e81ac0a1ed6e1111ba1d428b) https://bugzilla.redhat.com/show_bug.cgi?id=1558558 https://bugzilla.redhat.com/show_bug.cgi?id=1687515 Signed-off-by: Jiri Denemark Reviewed-by: Ján Tomko --- src/cpu/cpu_x86.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/src/cpu/cpu_x86.c b/src/cpu/cpu_x86.c index f6844aaa0d..466c79031d 100644 --- a/src/cpu/cpu_x86.c +++ b/src/cpu/cpu_x86.c @@ -1021,6 +1021,9 @@ x86ModelCopySignatures(virCPUx86ModelPtr dst, { size_t i; + if (src->nsignatures == 0) + return 0; + if (VIR_ALLOC_N(dst->signatures, src->nsignatures) < 0) return -1; -- 2.21.0