Fix for heap buffer overflow issue flagged by fuzzer test.
OOB write occurs when a value is assigned to a buffer index which is greater than the buffer size. Adding a check on buffer bounds fixes the issue.
Similar checks have been added wherever applicable on other such methods of the class.
Bug: 243463593
Test: Build mtp_packet_fuzzer and run on the target device
(cherry picked from commit a669e34bb8e6f0f7b5d7a35144bd342271a24712)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:0c26c2f4595b58bd7a11512227eacd480c4ddcd9)
Merged-In: Icd0f2307803a1a35e655bc08d9d4cca5e2b58a9b
Change-Id: Icd0f2307803a1a35e655bc08d9d4cca5e2b58a9b
diff --git a/media/mtp/MtpPacket.cpp b/media/mtp/MtpPacket.cpp
index f069a83..5faaac2 100644
--- a/media/mtp/MtpPacket.cpp
+++ b/media/mtp/MtpPacket.cpp
@@ -92,24 +92,46 @@
}
uint16_t MtpPacket::getUInt16(int offset) const {
- return ((uint16_t)mBuffer[offset + 1] << 8) | (uint16_t)mBuffer[offset];
+ if ((unsigned long)(offset+2) <= mBufferSize) {
+ return ((uint16_t)mBuffer[offset + 1] << 8) | (uint16_t)mBuffer[offset];
+ }
+ else {
+ ALOGE("offset for buffer read is greater than buffer size!");
+ abort();
+ }
}
uint32_t MtpPacket::getUInt32(int offset) const {
- return ((uint32_t)mBuffer[offset + 3] << 24) | ((uint32_t)mBuffer[offset + 2] << 16) |
- ((uint32_t)mBuffer[offset + 1] << 8) | (uint32_t)mBuffer[offset];
+ if ((unsigned long)(offset+4) <= mBufferSize) {
+ return ((uint32_t)mBuffer[offset + 3] << 24) | ((uint32_t)mBuffer[offset + 2] << 16) |
+ ((uint32_t)mBuffer[offset + 1] << 8) | (uint32_t)mBuffer[offset];
+ }
+ else {
+ ALOGE("offset for buffer read is greater than buffer size!");
+ abort();
+ }
}
void MtpPacket::putUInt16(int offset, uint16_t value) {
- mBuffer[offset++] = (uint8_t)(value & 0xFF);
- mBuffer[offset++] = (uint8_t)((value >> 8) & 0xFF);
+ if ((unsigned long)(offset+2) <= mBufferSize) {
+ mBuffer[offset++] = (uint8_t)(value & 0xFF);
+ mBuffer[offset++] = (uint8_t)((value >> 8) & 0xFF);
+ }
+ else {
+ ALOGE("offset for buffer write is greater than buffer size!");
+ }
}
void MtpPacket::putUInt32(int offset, uint32_t value) {
- mBuffer[offset++] = (uint8_t)(value & 0xFF);
- mBuffer[offset++] = (uint8_t)((value >> 8) & 0xFF);
- mBuffer[offset++] = (uint8_t)((value >> 16) & 0xFF);
- mBuffer[offset++] = (uint8_t)((value >> 24) & 0xFF);
+ if ((unsigned long)(offset+4) <= mBufferSize) {
+ mBuffer[offset++] = (uint8_t)(value & 0xFF);
+ mBuffer[offset++] = (uint8_t)((value >> 8) & 0xFF);
+ mBuffer[offset++] = (uint8_t)((value >> 16) & 0xFF);
+ mBuffer[offset++] = (uint8_t)((value >> 24) & 0xFF);
+ }
+ else {
+ ALOGE("offset for buffer write is greater than buffer size!");
+ }
}
uint16_t MtpPacket::getContainerCode() const {
