commit a03d37d542028e7cfaa3ad2ac44f7879a8297777
author Steven Moreland <smoreland@google.com> Tue Aug 04 21:20:36 2020 +0000
committer Android (Google) Code Review <android-gerrit@google.com> Tue Aug 04 21:20:36 2020 +0000
tree a10fb74555ab81b34073144f4a114087ab57c475
parent ea8d38e77f143cbab19b7deca44043a3632f9ab6
parent ee22384c54d42149491c8b9dbcda0d8c5e88eddc

Merge "libutils: check vsnprintf error" into oc-dev

libutils/String8.cpp

diff --git a/libutils/String8.cpp b/libutils/String8.cpp
index ad0e72e..8f9c9f7 100644
--- a/libutils/String8.cpp
+++ b/libutils/String8.cpp
@@ -346,8 +346,14 @@
     n = vsnprintf(NULL, 0, fmt, tmp_args);
     va_end(tmp_args);
 
-    if (n != 0) {
+    if (n < 0) return UNKNOWN_ERROR;
+
+    if (n > 0) {
         size_t oldLength = length();
+        if ((size_t)n > SIZE_MAX - 1 ||
+            oldLength > SIZE_MAX - (size_t)n - 1) {
+            return NO_MEMORY;
+        }
         char* buf = lockBuffer(oldLength + n);
         if (buf) {
             vsnprintf(buf + oldLength, n + 1, fmt, args);