Add support for Linux memory mapping stream and remove ELF header usage

when checking exploitability rating.

Linux minidumps do not support MD_MEMORY_INFO_LIST_STREAM, meaning the
processor cannot retrieve its memory mappings. However, it has its own
stream, MD_LINUX_MAPS, which contains memory mappings specific to Linux
(it contains the contents of /proc/self/maps). This CL allows the minidump
to gather information from the memory mappings for Linux minidumps.

In addition, exploitability rating for Linux dumps now use memory mappings
instead of checking the ELF headers of binaries. The basis for the change
is that checking the ELF headers requires the minidumps to store the memory
from the ELF headers, while the memory mapping data is already present,
meaning the size of a minidump will be unchanged.

As a result, of removing ELF header analysis, two unit tests have been removed.
Arguably, the cases that those unit tests check do not merit a high
exploitability rating and do not warrant a solid conclusion that was given
earlier.

R=ivanpe@chromium.org

Review URL: https://codereview.chromium.org/1251593007

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1476 4c0a9323-5329-0410-9bdc-e9ce6186880e

1 files changed, 57 insertions, 0 deletions

diff --git a/src/google_breakpad/processor/proc_maps_linux.h b/src/google_breakpad/processor/proc_maps_linux.h
new file mode 100644
index 00000000..6ddeb038
--- /dev/null
+++ b/src/google_breakpad/processor/proc_maps_linux.h
@@ -0,0 +1,57 @@
+// Copyright (c) 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.
+
+#ifndef BASE_DEBUG_PROC_MAPS_LINUX_H_
+#define BASE_DEBUG_PROC_MAPS_LINUX_H_
+
+#include <string>
+#include <vector>
+
+#include "common/using_std_string.h"
+#include "google_breakpad/common/breakpad_types.h"
+
+namespace google_breakpad {
+
+// Describes a region of mapped memory and the path of the file mapped.
+struct MappedMemoryRegion {
+  enum Permission {
+    READ = 1 << 0,
+    WRITE = 1 << 1,
+    EXECUTE = 1 << 2,
+    PRIVATE = 1 << 3,  // If set, region is private, otherwise it is shared.
+  };
+
+  // The address range [start,end) of mapped memory.
+  uintptr_t start;
+  uintptr_t end;
+
+  // Byte offset into |path| of the range mapped into memory.
+  uint64_t offset;
+
+  // Bitmask of read/write/execute/private/shared permissions.
+  uint8_t permissions;
+
+  // Major and minor devices.
+  uint8_t major_device;
+  uint8_t minor_device;
+
+  // Value of the inode.
+  uint64_t inode;
+
+  // Name of the file mapped into memory.
+  //
+  // NOTE: path names aren't guaranteed to point at valid files. For example,
+  // "[heap]" and "[stack]" are used to represent the location of the process'
+  // heap and stack, respectively.
+  string path;
+};
+
+// Parses /proc/<pid>/maps input data and stores in |regions|. Returns true
+// and updates |regions| if and only if all of |input| was successfully parsed.
+bool ParseProcMaps(const std::string& input,
+                   std::vector<MappedMemoryRegion>* regions);
+
+}  // namespace google_breakpad
+
+#endif  // BASE_DEBUG_PROC_MAPS_LINUX_H_