android_filesystem_config.h: change ping and run-as

/system/bin/ping no longer requires CAP_NET_RAW, as we're now
using IPPROTO_ICMP. Please see the following for more details:

* http://lwn.net/Articles/443051/
* https://android-review.googlesource.com/52090
* https://android-review.googlesource.com/52072

We can now make ping a normal, unprivileged program.

/system/bin/run-as only requires CAP_SETUID and CAP_SETGID.
Explicitly set the capabilities of this file, and remove
the setuid bit.

This is equivalent to running the following commands:

  * chmod 750 /system/bin/run-as
  * chown root:shell /system/bin/run-as
  * setcap cap_setgid,cap_setuid+ep /system/bin/run-as

Change-Id: I65df858b45e6de4e2190ac9d6d592c06ea9d28cf

2 files changed, 134 insertions, 8 deletions

diff --git a/include/private/android_filesystem_capability.h b/include/private/android_filesystem_capability.h
new file mode 100644
index 0000000..0505cda
--- /dev/null
+++ b/include/private/android_filesystem_capability.h
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Taken from linux/capability.h, with minor modifications
+ */
+
+#ifndef _SYSTEM_CORE_INCLUDE_PRIVATE_ANDROID_FILESYSTEM_CAPABILITY_H
+#define _SYSTEM_CORE_INCLUDE_PRIVATE_ANDROID_FILESYSTEM_CAPABILITY_H
+
+#include <stdint.h>
+
+#define __user
+#define __u32 uint32_t
+#define __le32 uint32_t
+
+#define _LINUX_CAPABILITY_VERSION_1 0x19980330
+#define _LINUX_CAPABILITY_U32S_1 1
+#define _LINUX_CAPABILITY_VERSION_2 0x20071026
+#define _LINUX_CAPABILITY_U32S_2 2
+#define _LINUX_CAPABILITY_VERSION_3 0x20080522
+#define _LINUX_CAPABILITY_U32S_3 2
+
+typedef struct __user_cap_header_struct {
+ __u32 version;
+ int pid;
+} __user *cap_user_header_t;
+
+typedef struct __user_cap_data_struct {
+ __u32 effective;
+ __u32 permitted;
+ __u32 inheritable;
+} __user *cap_user_data_t;
+
+#define VFS_CAP_REVISION_MASK 0xFF000000
+#define VFS_CAP_REVISION_SHIFT 24
+#define VFS_CAP_FLAGS_MASK ~VFS_CAP_REVISION_MASK
+#define VFS_CAP_FLAGS_EFFECTIVE 0x000001
+#define VFS_CAP_REVISION_1 0x01000000
+#define VFS_CAP_U32_1 1
+#define XATTR_CAPS_SZ_1 (sizeof(__le32)*(1 + 2*VFS_CAP_U32_1))
+#define VFS_CAP_REVISION_2 0x02000000
+#define VFS_CAP_U32_2 2
+#define XATTR_CAPS_SZ_2 (sizeof(__le32)*(1 + 2*VFS_CAP_U32_2))
+#define XATTR_CAPS_SZ XATTR_CAPS_SZ_2
+#define VFS_CAP_U32 VFS_CAP_U32_2
+#define VFS_CAP_REVISION VFS_CAP_REVISION_2
+
+struct vfs_cap_data {
+ __le32 magic_etc;
+ struct {
+ __le32 permitted;
+ __le32 inheritable;
+ } data[VFS_CAP_U32];
+};
+
+#define _LINUX_CAPABILITY_VERSION _LINUX_CAPABILITY_VERSION_1
+#define _LINUX_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_1
+#define CAP_CHOWN 0
+#define CAP_DAC_OVERRIDE 1
+#define CAP_DAC_READ_SEARCH 2
+#define CAP_FOWNER 3
+#define CAP_FSETID 4
+#define CAP_KILL 5
+#define CAP_SETGID 6
+#define CAP_SETUID 7
+#define CAP_SETPCAP 8
+#define CAP_LINUX_IMMUTABLE 9
+#define CAP_NET_BIND_SERVICE 10
+#define CAP_NET_BROADCAST 11
+#define CAP_NET_ADMIN 12
+#define CAP_NET_RAW 13
+#define CAP_IPC_LOCK 14
+#define CAP_IPC_OWNER 15
+#define CAP_SYS_MODULE 16
+#define CAP_SYS_RAWIO 17
+#define CAP_SYS_CHROOT 18
+#define CAP_SYS_PTRACE 19
+#define CAP_SYS_PACCT 20
+#define CAP_SYS_ADMIN 21
+#define CAP_SYS_BOOT 22
+#define CAP_SYS_NICE 23
+#define CAP_SYS_RESOURCE 24
+#define CAP_SYS_TIME 25
+#define CAP_SYS_TTY_CONFIG 26
+#define CAP_MKNOD 27
+#define CAP_LEASE 28
+#define CAP_AUDIT_WRITE 29
+#define CAP_AUDIT_CONTROL 30
+#define CAP_SETFCAP 31
+#define CAP_MAC_OVERRIDE 32
+#define CAP_MAC_ADMIN 33
+#define CAP_SYSLOG 34
+#define CAP_WAKE_ALARM 35
+#define CAP_LAST_CAP CAP_WAKE_ALARM
+#define cap_valid(x) ((x) >= 0 && (x) <= CAP_LAST_CAP)
+#define CAP_TO_INDEX(x) ((x) >> 5)
+#define CAP_TO_MASK(x) (1 << ((x) & 31))
+
+#undef __user
+#undef __u32
+#undef __le32
+
+#endif
diff --git a/include/private/android_filesystem_config.h b/include/private/android_filesystem_config.h
index 03df585..53bd166 100644
--- a/include/private/android_filesystem_config.h
+++ b/include/private/android_filesystem_config.h
@@ -27,6 +27,12 @@
 #include <sys/types.h>
 #include <stdint.h>
 
+#ifdef HAVE_ANDROID_OS
+#include <linux/capability.h>
+#else
+#include "android_filesystem_capability.h"
+#endif
+
 /* This is the master Users and Groups config for the platform.
 ** DO NOT EVER RENUMBER.
 */
@@ -206,21 +212,24 @@ static const struct fs_path_config android_files[] = {
     { 00644, AID_MEDIA_RW,  AID_MEDIA_RW,  0, "data/media/*" },
     { 00644, AID_SYSTEM,    AID_SYSTEM,    0, "data/app-private/*" },
     { 00644, AID_APP,       AID_APP,       0, "data/data/*" },
-        /* the following two files are INTENTIONALLY set-gid and not set-uid.
-         * Do not change. */
-    { 02755, AID_ROOT,      AID_NET_RAW,   0, "system/bin/ping" },
+    { 00755, AID_ROOT,      AID_ROOT,      0, "system/bin/ping" },
+
+    /* the following file is INTENTIONALLY set-gid and not set-uid.
+     * Do not change. */
     { 02750, AID_ROOT,      AID_INET,      0, "system/bin/netcfg" },
-    	/* the following five files are INTENTIONALLY set-uid, but they
-	 * are NOT included on user builds. */
+
+    /* the following five files are INTENTIONALLY set-uid, but they
+     * are NOT included on user builds. */
     { 06755, AID_ROOT,      AID_ROOT,      0, "system/xbin/su" },
     { 06755, AID_ROOT,      AID_ROOT,      0, "system/xbin/librank" },
     { 06755, AID_ROOT,      AID_ROOT,      0, "system/xbin/procrank" },
     { 06755, AID_ROOT,      AID_ROOT,      0, "system/xbin/procmem" },
     { 06755, AID_ROOT,      AID_ROOT,      0, "system/xbin/tcpdump" },
     { 04770, AID_ROOT,      AID_RADIO,     0, "system/bin/pppd-ril" },
-		/* the following file is INTENTIONALLY set-uid, and IS included
-		 * in user builds. */
-    { 06750, AID_ROOT,      AID_SHELL,     0, "system/bin/run-as" },
+
+    /* the following file has enhanced capabilities and IS included in user builds. */
+    { 00750, AID_ROOT,      AID_SHELL,     (1 << CAP_SETUID) | (1 << CAP_SETGID), "system/bin/run-as" },
+
     { 00755, AID_ROOT,      AID_SHELL,     0, "system/bin/*" },
     { 00755, AID_ROOT,      AID_ROOT,      0, "system/lib/valgrind/*" },
     { 00755, AID_ROOT,      AID_SHELL,     0, "system/xbin/*" },