commit bb34b0b398d116f22abea26c5902905afbf061db
author Steven Moreland <smoreland@google.com> Tue Aug 04 23:37:56 2020 +0000
committer Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com> Tue Aug 04 23:37:56 2020 +0000
tree 1443e8741df9aa77cb6410d23f52c97df24fe96b
parent 09ad43e72322420934ddb79f0df430e49114995c
parent e9fe87660b49b0f2e02963fbac07adcac2e7ae6b

Merge "libutils: check vsnprintf error" into oc-dev am: a03d37d542 am: d8801aaad8 am: d05ecb8d9d am: dc99a094dd am: 64b312bbd8 am: 0cb14f1fe7 am: ce44c8ac3c

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/core/+/12254459

Change-Id: I51d7fd41157708b398888aac7f70dd09c397ee81

libutils/String8.cpp

diff --git a/libutils/String8.cpp b/libutils/String8.cpp
index d13548e..9d50e0b 100644
--- a/libutils/String8.cpp
+++ b/libutils/String8.cpp
@@ -322,8 +322,14 @@
     n = vsnprintf(nullptr, 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);