1d30b3f1f6
This fixes a narrow security race in crontab. function old new delta xopen_as_uid_gid - 80 +80 seteuid - 64 +64 setegid - 64 +64 setreuid - 37 +37 xseteuid - 22 +22 xsetegid - 22 +22 crontab_main 590 577 -13 setfsuid 33 - -33 setfsgid 33 - -33 wall_main 138 102 -36 open_as_user 109 - -109 text data bss dec hex filename 893539 497 7568 901604 dc1e4 busybox_old 893618 497 7568 901683 dc233 busybox_unstripped Signed-off-by: Ryan Mallon <rmallon@gmail.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
64 lines
1.5 KiB
C
64 lines
1.5 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* wall - write a message to all logged-in users
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* Copyright (c) 2009 Bernhard Reutner-Fischer
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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//config:config WALL
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//config: bool "wall"
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//config: default y
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//config: depends on FEATURE_UTMP
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//config: help
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//config: Write a message to all users that are logged in.
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/* Needs to be run by root or be suid root - needs to write to /dev/TTY: */
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//applet:IF_WALL(APPLET(wall, BB_DIR_USR_BIN, BB_SUID_REQUIRE))
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//kbuild:lib-$(CONFIG_WALL) += wall.o
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//usage:#define wall_trivial_usage
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//usage: "[FILE]"
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//usage:#define wall_full_usage "\n\n"
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//usage: "Write content of FILE or stdin to all logged-in users"
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//usage:
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//usage:#define wall_sample_usage
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//usage: "echo foo | wall\n"
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//usage: "wall ./mymessage"
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#include "libbb.h"
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int wall_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int wall_main(int argc UNUSED_PARAM, char **argv)
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{
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struct utmp *ut;
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char *msg;
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int fd;
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fd = STDIN_FILENO;
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if (argv[1]) {
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/* The applet is setuid.
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* Access to the file must be under user's uid/gid.
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*/
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fd = xopen_as_uid_gid(argv[1], O_RDONLY, getuid(), getgid());
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}
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msg = xmalloc_read(fd, NULL);
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if (ENABLE_FEATURE_CLEAN_UP && argv[1])
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close(fd);
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setutent();
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while ((ut = getutent()) != NULL) {
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char *line;
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if (ut->ut_type != USER_PROCESS)
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continue;
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line = concat_path_file("/dev", ut->ut_line);
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xopen_xwrite_close(line, msg);
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free(line);
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}
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if (ENABLE_FEATURE_CLEAN_UP) {
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endutent();
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free(msg);
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}
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return EXIT_SUCCESS;
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}
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