Breakpad Linux: Fix flag value delimiter for ChromeOS

components/crash/app/breakpad_linux.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // For linux_syscall_support.h. This makes it safe to call embedded system
 // calls when in seccomp mode.
 
 #include "components/crash/app/breakpad_linux.h"
 
 #include <fcntl.h>
@@ skipping 952 matching lines @@
   char pid_buf[kUint64StringSize];
   uint64_t pid_str_length = my_uint64_len(info.pid);
   my_uint64tos(pid_buf, info.pid, pid_str_length);
   pid_buf[pid_str_length] = '\0';
 
   char uid_buf[kUint64StringSize];
   uid_t uid = geteuid();
   uint64_t uid_str_length = my_uint64_len(uid);
   my_uint64tos(uid_buf, uid, uid_str_length);
   uid_buf[uid_str_length] = '\0';
+
+  size_t buf_len = my_strlen(dumpfile);
+  char* chrome_flag = reinterpret_cast<char*>(allocator->Alloc(buf_len + 10));

[vapier, 2014/10/13 19:50:50]

this is C++ code, so why not just use std::string and not deal with all the
allocation yourself ?  this is not a critical fast path.

[stevefung, 2014/10/13 20:15:13]

I believe we can't use it, because this code runs in a compromised context. 
See: https://codereview.chromium.org/633833002/

+  my_strlcat(chrome_flag, "--chrome=", 9);

[Lei Zhang, 2014/10/10 19:11:47]

I think strlcat takes the size of the dest buffer, not the source buffer.

[stevefung, 2014/10/13 22:28:39]

Done.

+  my_strlcat(chrome_flag + 9, dumpfile, buf_len);
+
+  buf_len = my_strlen(pid_buf);
+  char* pid_flag = reinterpret_cast<char*>(allocator->Alloc(buf_len + 7));
+  my_strlcat(pid_flag, "--pid=", 6);
+  my_strlcat(pid_flag + 6, pid_buf, buf_len);
+
+  buf_len = my_strlen(uid_buf);
+  char* uid_flag = reinterpret_cast<char*>(allocator->Alloc(buf_len + 7));
+  my_strlcat(uid_flag, "--uid=", 6);
+  my_strlcat(uid_flag + 6, uid_buf, buf_len);
+
+  buf_len = my_strlen(exe_buf);
+  char* exe_flag = reinterpret_cast<char*>(allocator->Alloc(buf_len + 7));
+  my_strlcat(exe_flag, "--exe=", 6);
+  my_strlcat(exe_flag + 6, exe_buf, buf_len);
+
   const char* args[] = {
     kCrashReporterBinary,
-    "--chrome",
-    dumpfile,
-    "--pid",
-    pid_buf,
-    "--uid",
-    uid_buf,
-    "--exe",
-    exe_buf,
+    chrome_flag,
+    pid_flag,
+    uid_flag,
+    exe_flag,
     NULL,
   };
   static const char msg[] = "Cannot upload crash dump: cannot exec "
                             "/sbin/crash_reporter\n";
 #else
   // The --header argument to wget looks like:
   //   --header=Content-Type: multipart/form-data; boundary=XYZ
   // where the boundary has two fewer leading '-' chars
   static const char header_msg[] =
       "--header=Content-Type: multipart/form-data; boundary=";
@@ skipping 621 matching lines @@
     }
   }
 }
 #endif  // OS_ANDROID
 
 bool IsCrashReporterEnabled() {
   return g_is_crash_reporter_enabled;
 }
 
 }  // namespace breakpad