diff options
Diffstat (limited to 'su')
| -rw-r--r-- | su/Android.mk | 6 | ||||
| -rw-r--r-- | su/su.c | 136 |
2 files changed, 58 insertions, 84 deletions
diff --git a/su/Android.mk b/su/Android.mk index 0593cc96..297e0a31 100644 --- a/su/Android.mk +++ b/su/Android.mk @@ -1,14 +1,12 @@ LOCAL_PATH:= $(call my-dir) include $(CLEAR_VARS) +LOCAL_CFLAGS := -std=c11 -Wall -Werror + LOCAL_SRC_FILES:= su.c LOCAL_MODULE:= su -LOCAL_FORCE_STATIC_EXECUTABLE := true - -LOCAL_STATIC_LIBRARIES := libc - LOCAL_MODULE_PATH := $(TARGET_OUT_OPTIONAL_EXECUTABLES) LOCAL_MODULE_TAGS := debug @@ -1,54 +1,45 @@ /* -** -** Copyright 2008, 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. -*/ - -#define LOG_TAG "su" + * Copyright (C) 2008 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. + */ +#include <errno.h> +#include <error.h> +#include <pwd.h> #include <stdio.h> #include <stdlib.h> #include <string.h> -#include <sys/types.h> -#include <dirent.h> -#include <errno.h> - #include <unistd.h> -#include <time.h> - -#include <pwd.h> #include <private/android_filesystem_config.h> - -void pwtoid(const char *tok, uid_t *uid, gid_t *gid) -{ - struct passwd *pw; - pw = getpwnam(tok); +void pwtoid(const char* tok, uid_t* uid, gid_t* gid) { + struct passwd* pw = getpwnam(tok); if (pw) { if (uid) *uid = pw->pw_uid; if (gid) *gid = pw->pw_gid; } else { - uid_t tmpid = atoi(tok); + char* end; + errno = 0; + uid_t tmpid = strtoul(tok, &end, 10); + if (errno != 0 || end == tok) error(1, errno, "invalid uid/gid '%s'", tok); if (uid) *uid = tmpid; if (gid) *gid = tmpid; } } -void extract_uidgids(const char *uidgids, uid_t *uid, gid_t *gid, gid_t *gids, - int *gids_count) -{ +void extract_uidgids(const char* uidgids, uid_t* uid, gid_t* gid, gid_t* gids, int* gids_count) { char *clobberablegids; char *nexttok; char *tok; @@ -59,6 +50,7 @@ void extract_uidgids(const char *uidgids, uid_t *uid, gid_t *gid, gid_t *gids, *gids_count = 0; return; } + clobberablegids = strdup(uidgids); strcpy(clobberablegids, uidgids); nexttok = clobberablegids; @@ -87,7 +79,7 @@ void extract_uidgids(const char *uidgids, uid_t *uid, gid_t *gid, gid_t *gids, /* * SU can be given a specific command to exec. UID _must_ be - * specified for this (ie argc => 3). + * specified for this. * * Usage: * su 1000 @@ -99,61 +91,45 @@ void extract_uidgids(const char *uidgids, uid_t *uid, gid_t *gid, gid_t *gids, * will return * uid=1000(system) gid=2000(shell) groups=3006(net_bw_stats),3007(net_bw_acct) */ -int main(int argc, char **argv) -{ - struct passwd *pw; - uid_t uid, myuid; - gid_t gid, gids[10]; +int main(int argc, char** argv) { + uid_t current_uid = getuid(); + if (current_uid != AID_ROOT && current_uid != AID_SHELL) error(1, 0, "not allowed"); - /* Until we have something better, only root and the shell can use su. */ - myuid = getuid(); - if (myuid != AID_ROOT && myuid != AID_SHELL) { - fprintf(stderr,"su: uid %d not allowed to su\n", myuid); - return 1; - } + // The default user is root. + uid_t uid = 0; + gid_t gid = 0; - if(argc < 2) { - uid = gid = 0; - } else { + // TODO: use getopt and support at least -- and --help. + + // If there are any arguments, the first argument is the uid/gid/supplementary groups. + if (argc >= 2) { + gid_t gids[10]; int gids_count = sizeof(gids)/sizeof(gids[0]); extract_uidgids(argv[1], &uid, &gid, gids, &gids_count); - if(gids_count) { - if(setgroups(gids_count, gids)) { - fprintf(stderr, "su: failed to set groups\n"); - return 1; + if (gids_count) { + if (setgroups(gids_count, gids)) { + error(1, errno, "setgroups failed"); } } + ++argv; } - if(setgid(gid) || setuid(uid)) { - fprintf(stderr,"su: permission denied\n"); - return 1; - } + if (setgid(gid)) error(1, errno, "setgid failed"); + if (setuid(uid)) error(1, errno, "setuid failed"); - /* User specified command for exec. */ - if (argc == 3 ) { - if (execlp(argv[2], argv[2], NULL) < 0) { - int saved_errno = errno; - fprintf(stderr, "su: exec failed for %s Error:%s\n", argv[2], - strerror(errno)); - return -saved_errno; - } - } else if (argc > 3) { - /* Copy the rest of the args from main. */ - char *exec_args[argc - 1]; - memset(exec_args, 0, sizeof(exec_args)); - memcpy(exec_args, &argv[2], sizeof(exec_args)); - if (execvp(argv[2], exec_args) < 0) { - int saved_errno = errno; - fprintf(stderr, "su: exec failed for %s Error:%s\n", argv[2], - strerror(errno)); - return -saved_errno; - } - } + // TODO: reset $PATH. - /* Default exec shell. */ - execlp("/system/bin/sh", "sh", NULL); + // Set up the arguments for exec. + char* exec_args[argc]; // Having too much space is fine. + memset(exec_args, 0, sizeof(exec_args)); + // Skip "su" and copy any other args. We already skipped the optional uid above. + ++argv; + for (size_t i = 0; argv[i] != NULL; ++i) { + exec_args[i] = argv[i]; + } + // Default to the standard shell. + if (!exec_args[0]) exec_args[0] = "/system/bin/sh"; - fprintf(stderr, "su: exec failed\n"); - return 1; + execvp(exec_args[0], exec_args); + error(1, errno, "failed to exec %s", exec_args[0]); } |