Fix number parsing for max-age for HSTS/HPKP.

net/http/http_security_headers.cc

Index: net/http/http_security_headers.cc
diff --git a/net/http/http_security_headers.cc b/net/http/http_security_headers.cc
index 5174825cc9a86a7c8f530bccf6612a9a1957904a..93200b959c1200f016262db790b57bc4a41a7cbc 100644
--- a/net/http/http_security_headers.cc
+++ b/net/http/http_security_headers.cc
@@ -5,10 +5,10 @@
 #include <limits>
 
 #include "base/base64.h"
-#include "base/strings/string_number_conversions.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/string_tokenizer.h"
 #include "base/strings/string_util.h"
+#include "net/base/parse_number.h"
 #include "net/http/http_security_headers.h"
 #include "net/http/http_util.h"
 #include "url/gurl.h"
@@ -19,9 +19,6 @@ namespace {
 
 enum MaxAgeParsing { REQUIRE_MAX_AGE, DO_NOT_REQUIRE_MAX_AGE };
 
-static_assert(kMaxHSTSAgeSecs <= UINT32_MAX, "kMaxHSTSAgeSecs too large");
-static_assert(kMaxHPKPAgeSecs <= UINT32_MAX, "kMaxHPKPAgeSecs too large");
-
 // MaxAgeToLimitedInt converts a string representation of a "whole number" of
 // seconds into a uint32_t. The string may contain an arbitrarily large number,
 // which will be clipped to a supplied limit and which is guaranteed to fit
@@ -31,25 +28,19 @@ bool MaxAgeToLimitedInt(std::string::const_iterator begin,
                         uint32_t limit,
                         uint32_t* result) {
   const base::StringPiece s(begin, end);
-  if (s.empty())
-    return false;
 
-  int64_t i = 0;
+  ParseIntError error;
+  if (!ParseUint32(s, result, &error)) {
+    if (error == ParseIntError::FAILED_OVERFLOW) {
+      *result = limit;
+    } else {
+      return false;
+    }
+  }
+
+  if (*result > limit)
+    *result = limit;
 
-  // Return false on any StringToInt64 parse errors *except* for int64_t
-  // overflow. StringToInt64 is used, rather than StringToUint64, in order to
-  // properly handle and reject negative numbers (StringToUint64 does not return
-  // false on negative numbers). For values too large to be stored in an
-  // int64_t, StringToInt64 will return false with i set to
-  // std::numeric_limits<int64_t>::max(), so this case is allowed to fall
-  // through so that i gets clipped to limit.
-  if (!base::StringToInt64(s, &i) && i != std::numeric_limits<int64_t>::max())
-    return false;
-  if (i < 0)
-    return false;
-  if (i > limit)
-    i = limit;
-  *result = (uint32_t)i;
   return true;
 }