[libvirt] [PATCH] cpu: Don't access invalid memory in virCPUx86Translate
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 <mprivozn(a)redhat.com>
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
src/cpu/cpu_x86.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/src/cpu/cpu_x86.c b/src/cpu/cpu_x86.c
index 92941d1287..c8697819ab 100644
--- a/src/cpu/cpu_x86.c
+++ b/src/cpu/cpu_x86.c
@@ -987,6 +987,9 @@ x86ModelCopySignatures(virCPUx86ModelPtr dst,
{
size_t i;
+ if (src->nsignatures == 0)
+ return 0;
+
if (VIR_ALLOC_N(dst->signatures, src->nsignatures) < 0)
return -1;
@@ -2926,7 +2929,7 @@ virCPUx86Translate(virCPUDefPtr cpu,
virCPUx86DataAddCPUIDInt(&model->data, &model->vendor->cpuid)
< 0)
goto cleanup;
- if (model->signatures &&
+ if (model->nsignatures &&
x86DataAddSignature(&model->data, model->signatures[0]) < 0)
goto cleanup;
--
2.19.2