diff options
author | Sandeep Patil <sspatil@google.com> | 2017-08-21 12:17:19 -0700 |
---|---|---|
committer | Sandeep Patil <sspatil@google.com> | 2017-08-21 19:21:35 -0700 |
commit | aa3e32422cc7089b9b15976f2651a58840d95e4f (patch) | |
tree | bf447721950b57e04fe496316629cbdf3d59dc3c | |
parent | c88fe932733519e71c77d4fc4405fc38a6cba94d (diff) | |
download | bionic-aa3e32422cc7089b9b15976f2651a58840d95e4f.tar.gz |
libc: Add support to allow library calls to find appropriate shell executable for a process
Library calls like system() and popen() invoke the shell executable
pointed to by '_PATH_BSHELL' in order to run the command passed into the
function. The _PATH_BSHELL points to /system/bin/sh by default and thus
breaks any vendor process trying to use system() / popen(), as they are
denied access to system shell by selinux.
This CL make necessary changes, so the implmentations of system() and popen()
can use the appropriate shell (e.g. /vendor/bin/sh for processes running
out of /vendor partition). Also, changes the implementation of system()
and popen().
Bug: 64832610
Test: Manual, Using a test program running from /system/bin and
/vendor/bin to ensure correct shell is being used.
Change-Id: Ie7168d69decb1ae98284446ae7db34dec930dc33
Signed-off-by: Sandeep Patil <sspatil@google.com>
-rw-r--r-- | libc/Android.bp | 1 | ||||
-rw-r--r-- | libc/bionic/__bionic_get_shell_path.cpp | 51 | ||||
-rw-r--r-- | libc/include/paths.h | 2 | ||||
-rw-r--r-- | libc/upstream-netbsd/android/include/netbsd-compat.h | 4 | ||||
-rw-r--r-- | libc/upstream-openbsd/android/include/openbsd-compat.h | 4 |
5 files changed, 62 insertions, 0 deletions
diff --git a/libc/Android.bp b/libc/Android.bp index 7b0ac23f3..b5229cbbf 100644 --- a/libc/Android.bp +++ b/libc/Android.bp @@ -1331,6 +1331,7 @@ cc_library_static { defaults: ["libc_defaults"], srcs: [ "bionic/NetdClientDispatch.cpp", + "bionic/__bionic_get_shell_path.cpp", "bionic/__cmsg_nxthdr.cpp", "bionic/__errno.cpp", "bionic/__gnu_basename.cpp", diff --git a/libc/bionic/__bionic_get_shell_path.cpp b/libc/bionic/__bionic_get_shell_path.cpp new file mode 100644 index 000000000..477fa4a1b --- /dev/null +++ b/libc/bionic/__bionic_get_shell_path.cpp @@ -0,0 +1,51 @@ +/* + * Copyright (C) 2017 The Android Open Source Project + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, + * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT + * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <errno.h> +#include <string.h> +#include <sys/cdefs.h> +#include <unistd.h> + +__LIBC_HIDDEN__ static const char* __libc_system_sh = "/system/bin/sh"; +__LIBC_HIDDEN__ static const char* __libc_vendor_sh = "/vendor/bin/sh"; + +static const char* init_sh_path() { + /* look for /system or /vendor prefix */ + char exe_path[7]; + ssize_t len = readlink("/proc/self/exe", exe_path, sizeof(exe_path)); + if (len != -1 && !strncmp(exe_path, __libc_vendor_sh, sizeof(exe_path))) { + return __libc_vendor_sh; + } + + return __libc_system_sh; +} + +__LIBC_HIDDEN__ extern "C" const char* __bionic_get_shell_path() { + static const char* sh_path = init_sh_path(); + return sh_path; +} diff --git a/libc/include/paths.h b/libc/include/paths.h index b76d0454a..d2c5956a8 100644 --- a/libc/include/paths.h +++ b/libc/include/paths.h @@ -34,7 +34,9 @@ #include <sys/cdefs.h> +#ifndef _PATH_BSHELL #define _PATH_BSHELL "/system/bin/sh" +#endif #define _PATH_CONSOLE "/dev/console" #define _PATH_DEFPATH "/sbin:/system/sbin:/system/bin:/system/xbin:/vendor/bin:/vendor/xbin" #define _PATH_DEV "/dev/" diff --git a/libc/upstream-netbsd/android/include/netbsd-compat.h b/libc/upstream-netbsd/android/include/netbsd-compat.h index 45b974a6f..af5ae2927 100644 --- a/libc/upstream-netbsd/android/include/netbsd-compat.h +++ b/libc/upstream-netbsd/android/include/netbsd-compat.h @@ -44,4 +44,8 @@ #include <stddef.h> int reallocarr(void*, size_t, size_t); +/* Use appropriate shell depending on process's executable. */ +__LIBC_HIDDEN__ extern const char* __bionic_get_shell_path(); +#define _PATH_BSHELL __bionic_get_shell_path() + #endif diff --git a/libc/upstream-openbsd/android/include/openbsd-compat.h b/libc/upstream-openbsd/android/include/openbsd-compat.h index 9b16da70e..1e433beef 100644 --- a/libc/upstream-openbsd/android/include/openbsd-compat.h +++ b/libc/upstream-openbsd/android/include/openbsd-compat.h @@ -70,6 +70,10 @@ extern const char* __progname; */ #define _PATH_TMP "/data/local/tmp/" +/* Use appropriate shell depending on process's executable. */ +__LIBC_HIDDEN__ extern const char* __bionic_get_shell_path(); +#define _PATH_BSHELL __bionic_get_shell_path() + /* We have OpenBSD's getentropy_linux.c, but we don't mention getentropy in any header. */ __LIBC_HIDDEN__ extern int getentropy(void*, size_t); |