commit a88c8780e973dde2076b271e5e2213db44af3f1e
author serge-sans-paille <sguelton@redhat.com> Tue Mar 03 13:27:36 2020 +0100
committer Copybara-Service <copybara-worker@google.com> Thu Mar 25 23:20:51 2021 -0700
tree e8d95b645ac2f812fc169730d13c2412c8ce1a41
parent c1ba9387c4b3c61977962738566af0390867e179

Fix UB in compiler-rt base64 implementation

As a follow-up to 1454c27b60447d969d0c1ecaf20b2186fe9d85ec

GitOrigin-RevId: 292ab49d43a2b73295c8d5851d84de4608acc6ba

FuzzerUtil.cpp

diff --git a/FuzzerUtil.cpp b/FuzzerUtil.cpp
index 87180d1..7eecb68 100644
--- a/FuzzerUtil.cpp
+++ b/FuzzerUtil.cpp
@@ -161,20 +161,21 @@
 
   size_t i = 0, j = 0;
   for (size_t n = U.size() / 3 * 3; i < n; i += 3, j += 4) {
-    uint32_t x = (U[i] << 16) | (U[i + 1] << 8) | U[i + 2];
+    uint32_t x = ((unsigned char)U[i] << 16) | ((unsigned char)U[i + 1] << 8) |
+                 (unsigned char)U[i + 2];
     Buffer[j + 0] = Table[(x >> 18) & 63];
     Buffer[j + 1] = Table[(x >> 12) & 63];
     Buffer[j + 2] = Table[(x >> 6) & 63];
     Buffer[j + 3] = Table[x & 63];
   }
   if (i + 1 == U.size()) {
-    uint32_t x = (U[i] << 16);
+    uint32_t x = ((unsigned char)U[i] << 16);
     Buffer[j + 0] = Table[(x >> 18) & 63];
     Buffer[j + 1] = Table[(x >> 12) & 63];
     Buffer[j + 2] = '=';
     Buffer[j + 3] = '=';
   } else if (i + 2 == U.size()) {
-    uint32_t x = (U[i] << 16) | (U[i + 1] << 8);
+    uint32_t x = ((unsigned char)U[i] << 16) | ((unsigned char)U[i + 1] << 8);
     Buffer[j + 0] = Table[(x >> 18) & 63];
     Buffer[j + 1] = Table[(x >> 12) & 63];
     Buffer[j + 2] = Table[(x >> 6) & 63];