bplist: Fix integer overflow check (offset table size)
diff --git a/src/bplist.c b/src/bplist.c
index eede7a7..8e0dcd1 100644
--- a/src/bplist.c
+++ b/src/bplist.c
@@ -178,6 +178,19 @@
#define float_bswap32(x) (x)
#endif
+#ifndef __has_builtin
+#define __has_builtin(x) 0
+#endif
+
+#if __has_builtin(__builtin_umulll_overflow) || __GNUC__ >= 5
+#define uint64_mul_overflow(a, b, r) __builtin_umulll_overflow(a, b, r)
+#else
+static int uint64_mul_overflow(uint64_t a, uint64_t b, uint64_t *res)
+{
+ *res = a * b;
+ return (a > UINT64_MAX / b);
+}
+#endif
#define NODE_IS_ROOT(x) (((node_t*)x)->isRoot)
@@ -773,6 +786,7 @@
uint64_t num_objects = 0;
uint64_t root_object = 0;
const char *offset_table = NULL;
+ uint64_t offset_table_size = 0;
const char *start_data = NULL;
const char *end_data = NULL;
@@ -829,12 +843,12 @@
return;
}
- if (num_objects * offset_size < num_objects) {
- PLIST_BIN_ERR("integer overflow when calculating offset table size (too many objects)\n");
+ if (uint64_mul_overflow(num_objects, offset_size, &offset_table_size)) {
+ PLIST_BIN_ERR("integer overflow when calculating offset table size\n");
return;
}
- if ((uint64_t)offset_table + num_objects * offset_size > (uint64_t)end_data) {
+ if ((offset_table + offset_table_size < offset_table) || (offset_table + offset_table_size > end_data)) {
PLIST_BIN_ERR("offset table points outside of valid range\n");
return;
}