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authorEduardo Habkost <ehabkost@redhat.com>2018-01-09 13:45:13 -0200
committerEduardo Habkost <ehabkost@redhat.com>2018-01-17 23:04:31 -0200
commit807e9869b8c4119b81df902625af818519e01759 (patch)
tree3acb35c8261708235b64cfe3b0b72daebae44edc
parentc68bcb3a994a3647ea70899d050debb0ff72d86a (diff)
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i386: Change X86CPUDefinition::model_id to const char*
It is valid to have a 48-character model ID on CPUID, however the definition of X86CPUDefinition::model_id is char[48], which can make the compiler drop the null terminator from the string. If a CPU model happens to have 48 bytes on model_id, "-cpu help" will print garbage and the object_property_set_str() call at x86_cpu_load_def() will read data outside the model_id array. We could increase the array size to 49, but this would mean the compiler would not issue a warning if a 49-char string is used by mistake for model_id. To make things simpler, simply change model_id to be const char*, and validate the string length using an assert() on x86_register_cpudef_type(). Reported-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> Message-Id: <20180109154519.25634-2-ehabkost@redhat.com> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
-rw-r--r--target/i386/cpu.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 4385853..0e26fa4 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -754,7 +754,7 @@ struct X86CPUDefinition {
int model;
int stepping;
FeatureWordArray features;
- char model_id[48];
+ const char *model_id;
};
static X86CPUDefinition builtin_x86_defs[] = {
@@ -923,6 +923,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
.features[FEAT_1_EDX] =
I486_FEATURES,
.xlevel = 0,
+ .model_id = "",
},
{
.name = "pentium",
@@ -934,6 +935,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
.features[FEAT_1_EDX] =
PENTIUM_FEATURES,
.xlevel = 0,
+ .model_id = "",
},
{
.name = "pentium2",
@@ -945,6 +947,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
.features[FEAT_1_EDX] =
PENTIUM2_FEATURES,
.xlevel = 0,
+ .model_id = "",
},
{
.name = "pentium3",
@@ -956,6 +959,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
.features[FEAT_1_EDX] =
PENTIUM3_FEATURES,
.xlevel = 0,
+ .model_id = "",
},
{
.name = "athlon",
@@ -2736,6 +2740,9 @@ static void x86_register_cpudef_type(X86CPUDefinition *def)
* they shouldn't be set on the CPU model table.
*/
assert(!(def->features[FEAT_8000_0001_EDX] & CPUID_EXT2_AMD_ALIASES));
+ /* catch mistakes instead of silently truncating model_id when too long */
+ assert(def->model_id && strlen(def->model_id) <= 48);
+
type_register(&ti);
g_free(typename);