Merge "ResStringPool: Fix security vulnerability" into pi-dev
diff --git a/libs/androidfw/ResourceTypes.cpp b/libs/androidfw/ResourceTypes.cpp
index 985a756..7d4e6f8 100644
--- a/libs/androidfw/ResourceTypes.cpp
+++ b/libs/androidfw/ResourceTypes.cpp
@@ -456,6 +456,22 @@
uninit();
+ // The chunk must be at least the size of the string pool header.
+ if (size < sizeof(ResStringPool_header)) {
+ LOG_ALWAYS_FATAL("Bad string block: data size %zu is too small to be a string block", size);
+ return (mError=BAD_TYPE);
+ }
+
+ // The data is at least as big as a ResChunk_header, so we can safely validate the other
+ // header fields.
+ // `data + size` is safe because the source of `size` comes from the kernel/filesystem.
+ if (validate_chunk(reinterpret_cast<const ResChunk_header*>(data), sizeof(ResStringPool_header),
+ reinterpret_cast<const uint8_t*>(data) + size,
+ "ResStringPool_header") != NO_ERROR) {
+ LOG_ALWAYS_FATAL("Bad string block: malformed block dimensions");
+ return (mError=BAD_TYPE);
+ }
+
const bool notDeviceEndian = htods(0xf0) != 0xf0;
if (copyData || notDeviceEndian) {
@@ -467,6 +483,8 @@
data = mOwnedData;
}
+ // The size has been checked, so it is safe to read the data in the ResStringPool_header
+ // data structure.
mHeader = (const ResStringPool_header*)data;
if (notDeviceEndian) {