Variables can be allocated with or without specification, however,
tag__recode_dwarf_type() always tries accessing it, leading to heap
read overflows and subsequent logic bugs.
Fix by introducing a bit that tracks whether or not specification is
present.
Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
---
dwarf_loader.c | 15 ++++++++++-----
dwarves.h | 1 +
2 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/dwarf_loader.c b/dwarf_loader.c
index 48e1bf0..60bdca3 100644
--- a/dwarf_loader.c
+++ b/dwarf_loader.c
@@ -723,6 +723,7 @@ static struct variable *variable__new(Dwarf_Die *die, struct cu *cu, struct conf
var->external = dwarf_hasattr(die, DW_AT_external);
/* non-defining declaration of an object */
var->declaration = dwarf_hasattr(die, DW_AT_declaration);
+ var->has_specification = has_specification;
var->scope = VSCOPE_UNKNOWN;
INIT_LIST_HEAD(&var->annots);
var->ip.addr = 0;
@@ -2291,12 +2292,16 @@ static int tag__recode_dwarf_type(struct tag *tag, struct cu *cu)
goto find_type;
case DW_TAG_variable: {
struct variable *var = tag__variable(tag);
- dwarf_off_ref specification = dwarf_tag__spec(dtag);
- if (specification.off) {
- dtype = dwarf_cu__find_tag_by_ref(cu->priv, &specification);
- if (dtype)
- var->spec = tag__variable(dtype->tag);
+ if (var->has_specification) {
+ dwarf_off_ref specification = dwarf_tag__spec(dtag);
+
+ if (specification.off) {
+ dtype = dwarf_cu__find_tag_by_ref(cu->priv,
+ &specification);
+ if (dtype)
+ var->spec = tag__variable(dtype->tag);
+ }
}
}
diff --git a/dwarves.h b/dwarves.h
index 30d33fa..20608dd 100644
--- a/dwarves.h
+++ b/dwarves.h
@@ -691,6 +691,7 @@ struct variable {
const char *name;
uint8_t external:1;
uint8_t declaration:1;
+ uint8_t has_specification:1;
enum vscope scope;
struct location location;
struct hlist_node tool_hnode;
--
2.31.1
