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author | Fyodor Kupolov <fkupolov@google.com> | 2017-02-27 17:33:18 -0800 |
---|---|---|
committer | gitbuildkicker <android-build@google.com> | 2017-04-06 15:18:32 -0700 |
commit | f76189e459382e53a4dbfe40aab63a1cf6ff15eb (patch) | |
tree | 956a77738388642931bda7a4ff6803390d619ccf | |
parent | 6aa27238e1ebe6ec6a12a931b761b97373c017da (diff) | |
download | base-f76189e459382e53a4dbfe40aab63a1cf6ff15eb.tar.gz |
[DO NOT MERGE] Check bounds in offsetToPtr
Check whether specified offset belongs to mData.
Also added a default argument bufferSize to check the end offset.
Size of the ashmem descriptor can be modified between
ashmem_get_size_region call and mmap. createFromParcel method was updated
to check ashmem size again immediately after memory is mapped.
Test: manual - using the test app from the bug
Bug: 34128677
Change-Id: I3ecd1616a870ce20941ce9b20a1843d2b4295750
(cherry picked from commit 45e2e95c2ffeb2d978e2cce80b729ef6ada3b8d2)
(cherry picked from commit acede24109412a4c09e6e4e93d7b96bc9b1ad440)
-rw-r--r-- | include/androidfw/CursorWindow.h | 17 | ||||
-rw-r--r-- | libs/androidfw/CursorWindow.cpp | 5 |
2 files changed, 19 insertions, 3 deletions
diff --git a/include/androidfw/CursorWindow.h b/include/androidfw/CursorWindow.h index 8a2979a3756d..2eb349f57165 100644 --- a/include/androidfw/CursorWindow.h +++ b/include/androidfw/CursorWindow.h @@ -18,6 +18,7 @@ #define _ANDROID__DATABASE_WINDOW_H #include <cutils/log.h> +#include <inttypes.h> #include <stddef.h> #include <stdint.h> @@ -128,12 +129,13 @@ public: inline const char* getFieldSlotValueString(FieldSlot* fieldSlot, size_t* outSizeIncludingNull) { *outSizeIncludingNull = fieldSlot->data.buffer.size; - return static_cast<char*>(offsetToPtr(fieldSlot->data.buffer.offset)); + return static_cast<char*>(offsetToPtr( + fieldSlot->data.buffer.offset, fieldSlot->data.buffer.size)); } inline const void* getFieldSlotValueBlob(FieldSlot* fieldSlot, size_t* outSize) { *outSize = fieldSlot->data.buffer.size; - return offsetToPtr(fieldSlot->data.buffer.offset); + return offsetToPtr(fieldSlot->data.buffer.offset, fieldSlot->data.buffer.size); } private: @@ -166,7 +168,16 @@ private: bool mReadOnly; Header* mHeader; - inline void* offsetToPtr(uint32_t offset) { + inline void* offsetToPtr(uint32_t offset, uint32_t bufferSize = 0) { + if (offset >= mSize) { + ALOGE("Offset %" PRIu32 " out of bounds, max value %zu", offset, mSize); + return NULL; + } + if (offset + bufferSize > mSize) { + ALOGE("End offset %" PRIu32 " out of bounds, max value %zu", + offset + bufferSize, mSize); + return NULL; + } return static_cast<uint8_t*>(mData) + offset; } diff --git a/libs/androidfw/CursorWindow.cpp b/libs/androidfw/CursorWindow.cpp index 166863c0d91a..5694115f61aa 100644 --- a/libs/androidfw/CursorWindow.cpp +++ b/libs/androidfw/CursorWindow.cpp @@ -98,9 +98,14 @@ status_t CursorWindow::createFromParcel(Parcel* parcel, CursorWindow** outCursor if (dupAshmemFd < 0) { result = -errno; } else { + // the size of the ashmem descriptor can be modified between ashmem_get_size_region + // call and mmap, so we'll check again immediately after memory is mapped void* data = ::mmap(NULL, size, PROT_READ, MAP_SHARED, dupAshmemFd, 0); if (data == MAP_FAILED) { result = -errno; + } else if (ashmem_get_size_region(dupAshmemFd) != size) { + ::munmap(data, size); + result = BAD_VALUE; } else { CursorWindow* window = new CursorWindow(name, dupAshmemFd, data, size, true /*readOnly*/); |