libandroidfw hardening for IncFs

Migrate libandroifw to using incfs::util::map_ptr to prevent processes
from crashing when parsing the resources.arsc, parsing compiled xml,
files, and retrieving resource values.

This change propagates incremental failures to the JNI level where they
are raised as ResourcesNotFoundException.

Performance of ResourcesPerfWorkloads without change (time in
nanoseconds):
[1/3] com.android.resources.perf.PerfTest#youtube: PASSED (11.883s)
    youtube_ns_median: 93812805
    youtube_ns_standardDeviation: 4387062
    youtube_ns_mean: 94455597
[2/3] com.android.resources.perf.PerfTest#maps: PASSED (11.265s)
    maps_ns_standardDeviation: 2997543
    maps_ns_mean: 83480371
    maps_ns_median: 82210941
[3/3] com.android.resources.perf.PerfTest#gmail: PASSED (24.963s)
    gmail_ns_median: 266141091
    gmail_ns_standardDeviation: 3492043
    gmail_ns_mean: 267472765

With change and verification forcibly enabled for all apks
(including the framework-res.apk):
[1/3] com.android.resources.perf.PerfTest#youtube: PASSED (11.646s)
    youtube_ns_median: 101999396
    youtube_ns_standardDeviation: 4625782
    youtube_ns_mean: 102631770
[2/3] com.android.resources.perf.PerfTest#maps: PASSED (11.286s)
    maps_ns_standardDeviation: 2692088
    maps_ns_mean: 91326538
    maps_ns_median: 90519884
[3/3] com.android.resources.perf.PerfTest#gmail: PASSED (24.694s)
    gmail_ns_median: 290284442
    gmail_ns_standardDeviation: 5764632
    gmail_ns_mean: 291660464

With change and verification disabled:
[1/3] com.android.resources.perf.PerfTest#youtube: PASSED (11.748s)
    youtube_ns_median: 95490747
    youtube_ns_standardDeviation: 7282249
    youtube_ns_mean: 98442515
[2/3] com.android.resources.perf.PerfTest#maps: PASSED (10.862s)
    maps_ns_standardDeviation: 4484213
    maps_ns_mean: 87912988
    maps_ns_median: 86325549
[3/3] com.android.resources.perf.PerfTest#gmail: PASSED (24.034s)
    gmail_ns_median: 282175838
    gmail_ns_standardDeviation: 6560876
    gmail_ns_mean: 282869146

These tests were done on a Pixel 3 and with cpu settings configured by
libs/hwui/tests/scripts/prep_generic.sh:

 Locked CPUs 4,5,6,7 to 1459200 / 2803200 KHz
 Disabled CPUs 0,1,2,3

Bug: 160635104
Bug: 169423204
Test: boot device && atest ResourcesPerfWorkloads

Change-Id: I5cd1bc8a2257bffaba6ca4a1c96f4e6640106866

1 files changed, 19 insertions, 8 deletions

diff --git a/libs/androidfw/ChunkIterator.cpp b/libs/androidfw/ChunkIterator.cpp
index 8fc321968055..25c8aa64e492 100644
--- a/libs/androidfw/ChunkIterator.cpp
+++ b/libs/androidfw/ChunkIterator.cpp
@@ -15,6 +15,7 @@
  */
 
 #include "androidfw/Chunk.h"
+#include "androidfw/Util.h"
 
 #include "android-base/logging.h"
 
@@ -23,11 +24,11 @@ namespace android {
 Chunk ChunkIterator::Next() {
   CHECK(len_ != 0) << "called Next() after last chunk";
 
-  const ResChunk_header* this_chunk = next_chunk_;
+  const incfs::map_ptr<ResChunk_header> this_chunk = next_chunk_;
+  CHECK((bool) this_chunk) << "Next() called without verifying next chunk";
 
   // We've already checked the values of this_chunk, so safely increment.
-  next_chunk_ = reinterpret_cast<const ResChunk_header*>(
-      reinterpret_cast<const uint8_t*>(this_chunk) + dtohl(this_chunk->size));
+  next_chunk_ = this_chunk.offset(dtohl(this_chunk->size)).convert<ResChunk_header>();
   len_ -= dtohl(this_chunk->size);
 
   if (len_ != 0) {
@@ -36,7 +37,7 @@ Chunk ChunkIterator::Next() {
       VerifyNextChunk();
     }
   }
-  return Chunk(this_chunk);
+  return Chunk(this_chunk.verified());
 }
 
 // TODO(b/111401637) remove this and have full resource file verification
@@ -47,6 +48,13 @@ bool ChunkIterator::VerifyNextChunkNonFatal() {
     last_error_was_fatal_ = false;
     return false;
   }
+
+  if (!next_chunk_) {
+    last_error_ = "failed to read chunk from data";
+    last_error_was_fatal_ = false;
+    return false;
+  }
+
   const size_t size = dtohl(next_chunk_->size);
   if (size > len_) {
     last_error_ = "chunk size is bigger than given data";
@@ -58,12 +66,10 @@ bool ChunkIterator::VerifyNextChunkNonFatal() {
 
 // Returns false if there was an error.
 bool ChunkIterator::VerifyNextChunk() {
-  const uintptr_t header_start = reinterpret_cast<uintptr_t>(next_chunk_);
-
   // This data must be 4-byte aligned, since we directly
   // access 32-bit words, which must be aligned on
   // certain architectures.
-  if (header_start & 0x03) {
+  if (!util::IsFourByteAligned(next_chunk_)) {
     last_error_ = "header not aligned on 4-byte boundary";
     return false;
   }
@@ -73,6 +79,11 @@ bool ChunkIterator::VerifyNextChunk() {
     return false;
   }
 
+  if (!next_chunk_) {
+    last_error_ = "failed to read chunk from data";
+    return false;
+  }
+
   const size_t header_size = dtohs(next_chunk_->headerSize);
   const size_t size = dtohl(next_chunk_->size);
   if (header_size < sizeof(ResChunk_header)) {
@@ -90,7 +101,7 @@ bool ChunkIterator::VerifyNextChunk() {
     return false;
   }
 
-  if ((size | header_size) & 0x03) {
+  if ((size | header_size) & 0x03U) {
     last_error_ = "header sizes are not aligned on 4-byte boundary";
     return false;
   }