From 93fe51840ebf2e2ea0c29d3c5aa196e328129469 Mon Sep 17 00:00:00 2001 From: Martijn Coenen Date: Wed, 22 Jan 2020 10:46:25 +0100 Subject: Fix addition/overflow checks. For unsigned arithmetic, use: (a + b < a) to detect whether a+b wraps (a > c / b) to detect whether a*b > c Bug: 120078455 Test: builds and boots Change-Id: Ic4f4d44f7c0656caa115f90f4cfa130192914949 (cherry picked from commit da2f2fd0f4c4eeb498b4b0541719f4f34faf13e2) --- libs/binder/BufferedTextOutput.cpp | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'libs/binder/BufferedTextOutput.cpp') diff --git a/libs/binder/BufferedTextOutput.cpp b/libs/binder/BufferedTextOutput.cpp index 857bbf9510..2978b539d7 100644 --- a/libs/binder/BufferedTextOutput.cpp +++ b/libs/binder/BufferedTextOutput.cpp @@ -49,9 +49,10 @@ struct BufferedTextOutput::BufferState : public RefBase } status_t append(const char* txt, size_t len) { + if (len > SIZE_MAX - bufferPos) return NO_MEMORY; // overflow if ((len+bufferPos) > bufferSize) { + if ((len + bufferPos) > SIZE_MAX / 3) return NO_MEMORY; // overflow size_t newSize = ((len+bufferPos)*3)/2; - if (newSize < (len+bufferPos)) return NO_MEMORY; // overflow void* b = realloc(buffer, newSize); if (!b) return NO_MEMORY; buffer = (char*)b; -- cgit v1.2.3-59-g8ed1b