libutils: fix overflow in SharedBuffer [DO NOT MERGE]
See
https://code.google.com/p/android/issues/detail?id=181910
Bug: 22952485
(cherry picked from commit 66b6eb9490beeeabc804d790c1c4060ce047afd4)
Change-Id: I363f49b5b3c6b7b3ac08cba2c14d72c431588c5a
diff --git a/libutils/SharedBuffer.cpp b/libutils/SharedBuffer.cpp
index 3555fb7..947551a 100644
--- a/libutils/SharedBuffer.cpp
+++ b/libutils/SharedBuffer.cpp
@@ -14,9 +14,12 @@
* limitations under the License.
*/
+#define __STDC_LIMIT_MACROS
+#include <stdint.h>
#include <stdlib.h>
#include <string.h>
+#include <log/log.h>
#include <utils/SharedBuffer.h>
#include <utils/Atomic.h>
@@ -26,6 +29,11 @@
SharedBuffer* SharedBuffer::alloc(size_t size)
{
+ // Don't overflow if the combined size of the buffer / header is larger than
+ // size_max.
+ LOG_ALWAYS_FATAL_IF((size >= (SIZE_MAX - sizeof(SharedBuffer))),
+ "Invalid buffer size %zu", size);
+
SharedBuffer* sb = static_cast<SharedBuffer *>(malloc(sizeof(SharedBuffer) + size));
if (sb) {
sb->mRefs = 1;
@@ -52,7 +60,7 @@
memcpy(sb->data(), data(), size());
release();
}
- return sb;
+ return sb;
}
SharedBuffer* SharedBuffer::editResize(size_t newSize) const
@@ -60,6 +68,11 @@
if (onlyOwner()) {
SharedBuffer* buf = const_cast<SharedBuffer*>(this);
if (buf->mSize == newSize) return buf;
+ // Don't overflow if the combined size of the new buffer / header is larger than
+ // size_max.
+ LOG_ALWAYS_FATAL_IF((newSize >= (SIZE_MAX - sizeof(SharedBuffer))),
+ "Invalid buffer size %zu", newSize);
+
buf = (SharedBuffer*)realloc(buf, sizeof(SharedBuffer) + newSize);
if (buf != NULL) {
buf->mSize = newSize;