diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -2492,6 +2492,36 @@
 #define INIT_GLOB64
 #endif  // SANITIZER_INTERCEPT_GLOB64
 
+#if SANITIZER_INTERCEPT___B64_TO
+INTERCEPTOR(int, __b64_ntop, unsigned char const *src, SIZE_T srclength,
+            char *target, SIZE_T targsize) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, __b64_ntop, src, srclength, target, targsize);
+  COMMON_INTERCEPTOR_READ_RANGE(ctx, src, srclength);
+  int res = REAL(__b64_ntop)(src, srclength, target, targsize);
+  if (res >= 0)
+    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, target,
+                                   (SIZE_T)res < targsize ? res + 1 : targsize);
+  return res;
+}
+INTERCEPTOR(int, __b64_pton, char const *src, char *target, SIZE_T targsize) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, __b64_pton, src, target, targsize);
+  COMMON_INTERCEPTOR_READ_STRING(ctx, src, 0);
+  int res = REAL(__b64_pton)(src, target, targsize);
+  if (res >= 0)
+    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, target,
+                                   (SIZE_T)res < targsize ? res + 1 : targsize);
+  return res;
+}
+#  define INIT___B64_TO                    \
+    COMMON_INTERCEPT_FUNCTION(__b64_ntop); \
+    COMMON_INTERCEPT_FUNCTION(__b64_pton);
+#else  // SANITIZER_INTERCEPT___B64_TO
+#define INIT___B64_TO
+#endif  // SANITIZER_INTERCEPT___B64_TO
+
+
 #if SANITIZER_INTERCEPT_POSIX_SPAWN
 
 template <class RealSpawnPtr>
@@ -10392,6 +10422,7 @@
   INIT_TIME;
   INIT_GLOB;
   INIT_GLOB64;
+  INIT___B64_TO;
   INIT_POSIX_SPAWN;
   INIT_WAIT;
   INIT_WAIT4;
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
@@ -235,6 +235,7 @@
 #define SANITIZER_INTERCEPT_TIME SI_POSIX
 #define SANITIZER_INTERCEPT_GLOB (SI_GLIBC || SI_SOLARIS)
 #define SANITIZER_INTERCEPT_GLOB64 SI_GLIBC
+#define SANITIZER_INTERCEPT___B64_TO SI_LINUX
 #define SANITIZER_INTERCEPT_POSIX_SPAWN SI_POSIX
 #define SANITIZER_INTERCEPT_WAIT SI_POSIX
 #define SANITIZER_INTERCEPT_INET SI_POSIX
diff --git a/compiler-rt/test/msan/Linux/b64.cpp b/compiler-rt/test/msan/Linux/b64.cpp
new file mode 100644
--- /dev/null
+++ b/compiler-rt/test/msan/Linux/b64.cpp
@@ -0,0 +1,25 @@
+// RUN: %clangxx_msan -O0 %s -o %t -lresolv && %run %t %p 2>&1 | FileCheck %s
+
+//#include <iostream>
+#include <resolv.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+
+int main(int argc, char *argv[]) {
+  const char *src = "base64 test data";
+  size_t src_len = strlen(src);
+  size_t dst_len = ((src_len + 2) / 3) * 4 + 1;
+  char *dst = reinterpret_cast<char *>(malloc(dst_len));
+  int res = b64_ntop(reinterpret_cast<const unsigned char *>(src), src_len, dst,
+                     dst_len);
+  printf("%lu - %s\n", strlen(dst), dst);
+  // CHECK-NOT: Uninitialized bytes
+  // CHECK-NOT: WARNING: MemorySanitizer: use-of-uninitialized-value
+  unsigned char *target = reinterpret_cast<unsigned char *>(malloc(dst_len));
+  res = b64_pton(dst, target, dst_len);
+  printf("%lu - %s\n", strlen(reinterpret_cast<char *>(target)), target);
+  // CHECK-NOT: Uninitialized bytes
+  // CHECK-NOT: WARNING: MemorySanitizer: use-of-uninitialized-value
+  return 0;
+}