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author | Zach Riggle <riggle@google.com> | 2016-07-21 11:21:54 -0400 |
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committer | Zach Riggle <riggle@google.com> | 2016-07-21 11:21:54 -0400 |
commit | baf83616e73d5110cee6b369a9c674f4a4978102 (patch) | |
tree | 3100cf1219d474659b393b6d163475c472a64a4b /runconuid | |
parent | 68320c1559d2e806e62e60d61db9f4cf8b468124 (diff) | |
download | extras-baf83616e73d5110cee6b369a9c674f4a4978102.tar.gz |
Add runconuid command to xbin
Change-Id: Iebaabb316682acd4415673f1ef3727a25922225d
Diffstat (limited to 'runconuid')
-rw-r--r-- | runconuid/Android.mk | 15 | ||||
-rw-r--r-- | runconuid/MODULE_LICENSE_APACHE2 | 0 | ||||
-rw-r--r-- | runconuid/NOTICE | 190 | ||||
-rw-r--r-- | runconuid/runconuid.cpp | 230 |
4 files changed, 435 insertions, 0 deletions
diff --git a/runconuid/Android.mk b/runconuid/Android.mk new file mode 100644 index 00000000..c36baae2 --- /dev/null +++ b/runconuid/Android.mk @@ -0,0 +1,15 @@ +LOCAL_PATH:= $(call my-dir) +include $(CLEAR_VARS) + +LOCAL_CFLAGS := -std=c11 -Wall -Werror + +LOCAL_SRC_FILES:= runconuid.cpp + +LOCAL_MODULE:= runconuid + +LOCAL_MODULE_PATH := $(TARGET_OUT_OPTIONAL_EXECUTABLES) +LOCAL_MODULE_TAGS := debug + +LOCAL_STATIC_LIBRARIES := libselinux + +include $(BUILD_EXECUTABLE) diff --git a/runconuid/MODULE_LICENSE_APACHE2 b/runconuid/MODULE_LICENSE_APACHE2 new file mode 100644 index 00000000..e69de29b --- /dev/null +++ b/runconuid/MODULE_LICENSE_APACHE2 diff --git a/runconuid/NOTICE b/runconuid/NOTICE new file mode 100644 index 00000000..c5b1efa7 --- /dev/null +++ b/runconuid/NOTICE @@ -0,0 +1,190 @@ + + Copyright (c) 2005-2008, 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. + + 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. + + + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + + TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + + 1. Definitions. + + "License" shall mean the terms and conditions for use, reproduction, + and distribution as defined by Sections 1 through 9 of this document. + + "Licensor" shall mean the copyright owner or entity authorized by + the copyright owner that is granting the License. + + "Legal Entity" shall mean the union of the acting entity and all + other entities that control, are controlled by, or are under common + control with that entity. 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For the purposes + of this License, Derivative Works shall not include works that remain + separable from, or merely link (or bind by name) to the interfaces of, + the Work and Derivative Works thereof. + + "Contribution" shall mean any work of authorship, including + the original version of the Work and any modifications or additions + to that Work or Derivative Works thereof, that is intentionally + submitted to Licensor for inclusion in the Work by the copyright owner + or by an individual or Legal Entity authorized to submit on behalf of + the copyright owner. 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If You + institute patent litigation against any entity (including a + cross-claim or counterclaim in a lawsuit) alleging that the Work + or a Contribution incorporated within the Work constitutes direct + or contributory patent infringement, then any patent licenses + granted to You under this License for that Work shall terminate + as of the date such litigation is filed. + + 4. Redistribution. You may reproduce and distribute copies of the + Work or Derivative Works thereof in any medium, with or without + modifications, and in Source or Object form, provided that You + meet the following conditions: + + (a) You must give any other recipients of the Work or + Derivative Works a copy of this License; and + + (b) You must cause any modified files to carry prominent notices + stating that You changed the files; and + + (c) You must retain, in the Source form of any Derivative Works + that You distribute, all copyright, patent, trademark, and + attribution notices from the Source form of the Work, + excluding those notices that do not pertain to any part of + the Derivative Works; and + + (d) If the Work includes a "NOTICE" text file as part of its + distribution, then any Derivative Works that You distribute must + include a readable copy of the attribution notices contained + within such NOTICE file, excluding those notices that do not + pertain to any part of the Derivative Works, in at least one + of the following places: within a NOTICE text file distributed + as part of the Derivative Works; within the Source form or + documentation, if provided along with the Derivative Works; or, + within a display generated by the Derivative Works, if and + wherever such third-party notices normally appear. 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In no event and under no legal theory, + whether in tort (including negligence), contract, or otherwise, + unless required by applicable law (such as deliberate and grossly + negligent acts) or agreed to in writing, shall any Contributor be + liable to You for damages, including any direct, indirect, special, + incidental, or consequential damages of any character arising as a + result of this License or out of the use or inability to use the + Work (including but not limited to damages for loss of goodwill, + work stoppage, computer failure or malfunction, or any and all + other commercial damages or losses), even if such Contributor + has been advised of the possibility of such damages. + + 9. Accepting Warranty or Additional Liability. While redistributing + the Work or Derivative Works thereof, You may choose to offer, + and charge a fee for, acceptance of support, warranty, indemnity, + or other liability obligations and/or rights consistent with this + License. However, in accepting such obligations, You may act only + on Your own behalf and on Your sole responsibility, not on behalf + of any other Contributor, and only if You agree to indemnify, + defend, and hold each Contributor harmless for any liability + incurred by, or claims asserted against, such Contributor by reason + of your accepting any such warranty or additional liability. + + END OF TERMS AND CONDITIONS + diff --git a/runconuid/runconuid.cpp b/runconuid/runconuid.cpp new file mode 100644 index 00000000..496d51f1 --- /dev/null +++ b/runconuid/runconuid.cpp @@ -0,0 +1,230 @@ +/* + * Copyright (C) 2016 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. + */ +const char* optstr = "<1u:g:G:c:s"; +const char* usage = + R"(usage: runconuid [-s] [-u UID] [-g GID] [-G GROUPS] [-c CONTEXT] COMMAND ARGS + +Run a command in the specified security context, as the specified user, +with the specified group membership. + +-c SELinux context +-g Group ID by name or numeric value +-G List of groups by name or numeric value +-s Set enforcing mode +-u User ID by name or numeric value +)"; + +#include <assert.h> +#include <grp.h> +#include <pwd.h> +#include <selinux/selinux.h> +#include <stdio.h> +#include <stdlib.h> +#include <signal.h> +#include <sys/ptrace.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <unistd.h> + +static uid_t uid = -1; +static gid_t gid = -1; +static gid_t* groups = nullptr; +static size_t ngroups = 0; +static char* context = nullptr; +static bool setenforce = false; +static char** child_argv = nullptr; + +[[noreturn]] void perror_exit(const char* message) { + perror(message); + exit(1); +} + +void do_child(void) { + if (context && setexeccon(context) < 0) { + perror_exit("Setting context to failed"); + } + + if (ngroups && setgroups(ngroups, groups) < 0) { + perror_exit("Setting supplementary groups failed."); + } + + if (gid != (gid_t) -1 && setresgid(gid, gid, gid) < 0) { + perror_exit("Setting group failed."); + } + + if (uid != (uid_t) -1 && setresuid(uid, uid, uid) < 0) { + perror_exit("Setting user failed."); + } + + ptrace(PTRACE_TRACEME, 0, 0, 0); + raise(SIGSTOP); + execvp(child_argv[0], child_argv); + perror_exit("Failed to execve"); +} + +uid_t lookup_uid(char* c) { + struct passwd* pw; + uid_t u; + + if (sscanf(c, "%d", &u) == 1) { + return u; + } + + if ((pw = getpwnam(c)) != 0) { + return pw->pw_uid; + } + + perror_exit("Could not resolve user ID by name"); +} + +gid_t lookup_gid(char* c) { + struct group* gr; + gid_t g; + + if (sscanf(c, "%d", &g) == 1) { + return g; + } + + if ((gr = getgrnam(c)) != 0) { + return gr->gr_gid; + } + + perror_exit("Could not resolve group ID by name"); +} + +void lookup_groups(char* c) { + char* group; + + // Count the number of groups + for (group = c; *group; group++) { + if (*group == ',') { + ngroups++; + *group = '\0'; + } + } + + // The last group is not followed by a comma. + ngroups++; + + // Allocate enough space for all of them + groups = (gid_t*)calloc(ngroups, sizeof(gid_t)); + group = c; + + // Fill in the group IDs + for (size_t n = 0; n < ngroups; n++) { + groups[n] = lookup_gid(group); + group += strlen(group) + 1; + } +} + +void parse_arguments(int argc, char** argv) { + int c; + + while ((c = getopt(argc, argv, optstr)) != -1) { + switch (c) { + case 'u': + uid = lookup_uid(optarg); + break; + case 'g': + gid = lookup_gid(optarg); + break; + case 'G': + lookup_groups(optarg); + break; + case 's': + setenforce = true; + break; + case 'c': + context = optarg; + break; + default: + perror_exit(usage); + break; + } + } + + child_argv = &argv[optind]; + + if (optind == argc) { + perror_exit(usage); + } +} + +int main(int argc, char** argv) { + pid_t child; + + parse_arguments(argc, argv); + child = fork(); + + if (child < 0) { + perror_exit("Could not fork."); + } + + if (setenforce && is_selinux_enabled()) { + if (security_setenforce(0) < 0) { + perror("Couldn't set enforcing status to 0"); + } + } + + if (child == 0) { + do_child(); + } + + if (ptrace(PTRACE_ATTACH, child, 0, 0) < 0) { + int err = errno; + kill(SIGKILL, child); + errno = err; + perror_exit("Could not ptrace child."); + } + + // Wait for the SIGSTOP + int status = 0; + if (-1 == wait(&status)) { + perror_exit("Could not wait for child SIGSTOP"); + } + + // Trace all syscalls. + ptrace(PTRACE_SETOPTIONS, child, 0, PTRACE_O_TRACESYSGOOD); + + while (1) { + ptrace(PTRACE_SYSCALL, child, 0, 0); + waitpid(child, &status, 0); + + // Child raises SIGINT after the execve, on the first instruction. + if (WIFSTOPPED(status) && WSTOPSIG(status) == SIGTRAP) { + break; + } + + // Child did some other syscall. + if (WIFSTOPPED(status) && WSTOPSIG(status) & 0x80) { + continue; + } + + // Child exited. + if (WIFEXITED(status)) { + exit(WEXITSTATUS(status)); + } + } + + if (setenforce && is_selinux_enabled()) { + if (security_setenforce(1) < 0) { + perror("Couldn't set enforcing status to 1"); + } + } + + ptrace(PTRACE_DETACH, child, 0, 0); + return 0; +} |