diff options
Diffstat (limited to 'applets')
| -rw-r--r-- | applets/applets.c | 541 |
1 files changed, 6 insertions, 535 deletions
diff --git a/applets/applets.c b/applets/applets.c index 3b4f395c9..bbf150c79 100644 --- a/applets/applets.c +++ b/applets/applets.c @@ -1,21 +1,15 @@ /* vi: set sw=4 ts=4: */ /* - * Utility routines. + * Stub for linking busybox binary against libbusybox. * - * Copyright (C) tons of folks. Tracking down who wrote what - * isn't something I'm going to worry about... If you wrote something - * here, please feel free to acknowledge your work. + * Copyright (C) 2007 Denis Vlasenko * - * Based in part on code from sash, Copyright (c) 1999 by David I. Bell - * Permission has been granted to redistribute this code under the GPL. - * - * Licensed under GPLv2 or later, see file License in this tarball for details. + * Licensed under GPLv2, see file License in this tarball for details. */ #include <assert.h> #include "busybox.h" - /* Apparently uclibc defines __GLIBC__ (compat trick?). Oh well. */ #if ENABLE_STATIC && defined(__GLIBC__) && !defined(__UCLIBC__) #warning Static linking against glibc produces buggy executables @@ -27,532 +21,9 @@ #error Aborting compilation. #endif - -const char *applet_name; -#if !BB_MMU -bool re_execed; -#endif - -USE_FEATURE_SUID(static uid_t ruid;) /* real uid */ - -#if ENABLE_FEATURE_SUID_CONFIG - -/* applets[] is const, so we have to define this "override" structure */ -static struct BB_suid_config { - const struct bb_applet *m_applet; - uid_t m_uid; - gid_t m_gid; - mode_t m_mode; - struct BB_suid_config *m_next; -} *suid_config; - -static bool suid_cfg_readable; - -/* check if u is member of group g */ -static int ingroup(uid_t u, gid_t g) -{ - struct group *grp = getgrgid(g); - - if (grp) { - char **mem; - - for (mem = grp->gr_mem; *mem; mem++) { - struct passwd *pwd = getpwnam(*mem); - - if (pwd && (pwd->pw_uid == u)) - return 1; - } - } - return 0; -} - -/* This should probably be a libbb routine. In that case, - * I'd probably rename it to something like bb_trimmed_slice. - */ -static char *get_trimmed_slice(char *s, char *e) -{ - /* First, consider the value at e to be nul and back up until we - * reach a non-space char. Set the char after that (possibly at - * the original e) to nul. */ - while (e-- > s) { - if (!isspace(*e)) { - break; - } - } - e[1] = '\0'; - - /* Next, advance past all leading space and return a ptr to the - * first non-space char; possibly the terminating nul. */ - return skip_whitespace(s); -} - -/* Don't depend on the tools to combine strings. */ -static const char config_file[] ALIGN1 = "/etc/busybox.conf"; - -/* We don't supply a value for the nul, so an index adjustment is - * necessary below. Also, we use unsigned short here to save some - * space even though these are really mode_t values. */ -static const unsigned short mode_mask[] ALIGN2 = { - /* SST sst xxx --- */ - S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */ - S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */ - 0, S_IXOTH, S_IXOTH, 0 /* other */ -}; - -#define parse_error(x) do { errmsg = x; goto pe_label; } while (0) - -static void parse_config_file(void) -{ - struct BB_suid_config *sct_head; - struct BB_suid_config *sct; - const struct bb_applet *applet; - FILE *f; - const char *errmsg; - char *s; - char *e; - int i; - unsigned lc; - smallint section; - char buffer[256]; - struct stat st; - - assert(!suid_config); /* Should be set to NULL by bss init. */ - - ruid = getuid(); - if (ruid == 0) /* run by root - don't need to even read config file */ - return; - - if ((stat(config_file, &st) != 0) /* No config file? */ - || !S_ISREG(st.st_mode) /* Not a regular file? */ - || (st.st_uid != 0) /* Not owned by root? */ - || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */ - || !(f = fopen(config_file, "r")) /* Cannot open? */ - ) { - return; - } - - suid_cfg_readable = 1; - sct_head = NULL; - section = lc = 0; - - while (1) { - s = buffer; - - if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */ - if (ferror(f)) { /* Make sure it wasn't a read error. */ - parse_error("reading"); - } - fclose(f); - suid_config = sct_head; /* Success, so set the pointer. */ - return; - } - - lc++; /* Got a (partial) line. */ - - /* If a line is too long for our buffer, we consider it an error. - * The following test does mistreat one corner case though. - * If the final line of the file does not end with a newline and - * yet exactly fills the buffer, it will be treated as too long - * even though there isn't really a problem. But it isn't really - * worth adding code to deal with such an unlikely situation, and - * we do err on the side of caution. Besides, the line would be - * too long if it did end with a newline. */ - if (!strchr(s, '\n') && !feof(f)) { - parse_error("line too long"); - } - - /* Trim leading and trailing whitespace, ignoring comments, and - * check if the resulting string is empty. */ - s = get_trimmed_slice(s, strchrnul(s, '#')); - if (!*s) { - continue; - } - - /* Check for a section header. */ - - if (*s == '[') { - /* Unlike the old code, we ignore leading and trailing - * whitespace for the section name. We also require that - * there are no stray characters after the closing bracket. */ - e = strchr(s, ']'); - if (!e /* Missing right bracket? */ - || e[1] /* Trailing characters? */ - || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */ - ) { - parse_error("section header"); - } - /* Right now we only have one section so just check it. - * If more sections are added in the future, please don't - * resort to cascading ifs with multiple strcasecmp calls. - * That kind of bloated code is all too common. A loop - * and a string table would be a better choice unless the - * number of sections is very small. */ - if (strcasecmp(s, "SUID") == 0) { - section = 1; - continue; - } - section = -1; /* Unknown section so set to skip. */ - continue; - } - - /* Process sections. */ - - if (section == 1) { /* SUID */ - /* Since we trimmed leading and trailing space above, we're - * now looking for strings of the form - * <key>[::space::]*=[::space::]*<value> - * where both key and value could contain inner whitespace. */ - - /* First get the key (an applet name in our case). */ - e = strchr(s, '='); - if (e) { - s = get_trimmed_slice(s, e); - } - if (!e || !*s) { /* Missing '=' or empty key. */ - parse_error("keyword"); - } - - /* Ok, we have an applet name. Process the rhs if this - * applet is currently built in and ignore it otherwise. - * Note: this can hide config file bugs which only pop - * up when the busybox configuration is changed. */ - applet = find_applet_by_name(s); - if (applet) { - /* Note: We currently don't check for duplicates! - * The last config line for each applet will be the - * one used since we insert at the head of the list. - * I suppose this could be considered a feature. */ - sct = xmalloc(sizeof(struct BB_suid_config)); - sct->m_applet = applet; - sct->m_mode = 0; - sct->m_next = sct_head; - sct_head = sct; - - /* Get the specified mode. */ - - e = skip_whitespace(e+1); - - for (i = 0; i < 3; i++) { - /* There are 4 chars + 1 nul for each of user/group/other. */ - static const char mode_chars[] ALIGN1 = "Ssx-\0" "Ssx-\0" "Ttx-"; - - const char *q; - q = strchrnul(mode_chars + 5*i, *e++); - if (!*q) { - parse_error("mode"); - } - /* Adjust by -i to account for nul. */ - sct->m_mode |= mode_mask[(q - mode_chars) - i]; - } - - /* Now get the the user/group info. */ - - s = skip_whitespace(e); - - /* Note: we require whitespace between the mode and the - * user/group info. */ - if ((s == e) || !(e = strchr(s, '.'))) { - parse_error("<uid>.<gid>"); - } - *e++ = '\0'; - - /* We can't use get_ug_id here since it would exit() - * if a uid or gid was not found. Oh well... */ - sct->m_uid = bb_strtoul(s, NULL, 10); - if (errno) { - struct passwd *pwd = getpwnam(s); - if (!pwd) { - parse_error("user"); - } - sct->m_uid = pwd->pw_uid; - } - - sct->m_gid = bb_strtoul(e, NULL, 10); - if (errno) { - struct group *grp; - grp = getgrnam(e); - if (!grp) { - parse_error("group"); - } - sct->m_gid = grp->gr_gid; - } - } - continue; - } - - /* Unknown sections are ignored. */ - - /* Encountering configuration lines prior to seeing a - * section header is treated as an error. This is how - * the old code worked, but it may not be desirable. - * We may want to simply ignore such lines in case they - * are used in some future version of busybox. */ - if (!section) { - parse_error("keyword outside section"); - } - - } /* while (1) */ - - pe_label: - fprintf(stderr, "Parse error in %s, line %d: %s\n", - config_file, lc, errmsg); - - fclose(f); - /* Release any allocated memory before returning. */ - while (sct_head) { - sct = sct_head->m_next; - free(sct_head); - sct_head = sct; - } -} -#else -static inline void parse_config_file(void) -{ - USE_FEATURE_SUID(ruid = getuid();) -} -#endif /* FEATURE_SUID_CONFIG */ - - -#if ENABLE_FEATURE_SUID -static void check_suid(const struct bb_applet *applet) -{ - gid_t rgid; /* real gid */ - - if (ruid == 0) /* set by parse_config_file() */ - return; /* run by root - no need to check more */ - rgid = getgid(); - -#if ENABLE_FEATURE_SUID_CONFIG - if (suid_cfg_readable) { - uid_t uid; - struct BB_suid_config *sct; - mode_t m; - - for (sct = suid_config; sct; sct = sct->m_next) { - if (sct->m_applet == applet) - goto found; - } - /* default: drop all privileges */ - xsetgid(rgid); - xsetuid(ruid); - return; - found: - m = sct->m_mode; - if (sct->m_uid == ruid) - /* same uid */ - m >>= 6; - else if ((sct->m_gid == rgid) || ingroup(ruid, sct->m_gid)) - /* same group / in group */ - m >>= 3; - - if (!(m & S_IXOTH)) /* is x bit not set ? */ - bb_error_msg_and_die("you have no permission to run this applet!"); - - /* _both_ sgid and group_exec have to be set for setegid */ - if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) - rgid = sct->m_gid; - /* else (no setegid) we will set egid = rgid */ - - /* We set effective AND saved ids. If saved-id is not set - * like we do below, seteiud(0) can still later succeed! */ - if (setresgid(-1, rgid, rgid)) - bb_perror_msg_and_die("setresgid"); - - /* do we have to set effective uid? */ - uid = ruid; - if (sct->m_mode & S_ISUID) - uid = sct->m_uid; - /* else (no seteuid) we will set euid = ruid */ - - if (setresuid(-1, uid, uid)) - bb_perror_msg_and_die("setresuid"); - return; - } -#if !ENABLE_FEATURE_SUID_CONFIG_QUIET - { - static bool onetime = 0; - - if (!onetime) { - onetime = 1; - fprintf(stderr, "Using fallback suid method\n"); - } - } -#endif -#endif - - if (applet->need_suid == _BB_SUID_ALWAYS) { - /* Real uid is not 0. If euid isn't 0 too, suid bit - * is most probably not set on our executable */ - if (geteuid()) - bb_error_msg_and_die("applet requires root privileges!"); - } else if (applet->need_suid == _BB_SUID_NEVER) { - xsetgid(rgid); /* drop all privileges */ - xsetuid(ruid); - } -} -#else -#define check_suid(x) ((void)0) -#endif /* FEATURE_SUID */ - - -#if ENABLE_FEATURE_INSTALLER -/* create (sym)links for each applet */ -static void install_links(const char *busybox, int use_symbolic_links) -{ - /* directory table - * this should be consistent w/ the enum, - * busybox.h::bb_install_loc_t, or else... */ - static const char usr_bin [] ALIGN1 = "/usr/bin"; - static const char usr_sbin[] ALIGN1 = "/usr/sbin"; - static const char *const install_dir[] = { - &usr_bin [8], /* "", equivalent to "/" for concat_path_file() */ - &usr_bin [4], /* "/bin" */ - &usr_sbin[4], /* "/sbin" */ - usr_bin, - usr_sbin - }; - - int (*lf)(const char *, const char *) = link; - char *fpc; - int i; - int rc; - - if (use_symbolic_links) - lf = symlink; - - for (i = 0; applets[i].name != NULL; i++) { - fpc = concat_path_file( - install_dir[applets[i].install_loc], - applets[i].name); - rc = lf(busybox, fpc); - if (rc != 0 && errno != EEXIST) { - bb_simple_perror_msg(fpc); - } - free(fpc); - } -} -#else -#define install_links(x,y) ((void)0) -#endif /* FEATURE_INSTALLER */ - - -/* If we were called as "busybox..." */ -static int busybox_main(char **argv) -{ - if (!argv[1]) { - /* Called without arguments */ - const struct bb_applet *a; - int col, output_width; - help: - output_width = 80; - if (ENABLE_FEATURE_AUTOWIDTH) { - /* Obtain the terminal width */ - get_terminal_width_height(0, &output_width, NULL); - } - /* leading tab and room to wrap */ - output_width -= sizeof("start-stop-daemon, ") + 8; - - printf("%s multi-call binary\n", bb_banner); /* reuse const string... */ - printf("Copyright (C) 1998-2006 Erik Andersen, Rob Landley, and others.\n" - "Licensed under GPLv2. See source distribution for full notice.\n" - "\n" - "Usage: busybox [function] [arguments]...\n" - " or: [function] [arguments]...\n" - "\n" - "\tBusyBox is a multi-call binary that combines many common Unix\n" - "\tutilities into a single executable. Most people will create a\n" - "\tlink to busybox for each function they wish to use and BusyBox\n" - "\twill act like whatever it was invoked as!\n" - "\nCurrently defined functions:\n"); - col = 0; - a = applets; - while (a->name) { - if (col > output_width) { - puts(","); - col = 0; - } - col += printf("%s%s", (col ? ", " : "\t"), a->name); - a++; - } - puts("\n"); - return 0; - } - - if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) { - const char *busybox; - busybox = xmalloc_readlink(bb_busybox_exec_path); - if (!busybox) - busybox = bb_busybox_exec_path; - /* -s makes symlinks */ - install_links(busybox, argv[2] && strcmp(argv[2], "-s") == 0); - return 0; - } - - if (strcmp(argv[1], "--help") == 0) { - /* "busybox --help [<applet>]" */ - if (!argv[2]) - goto help; - /* convert to "<applet> --help" */ - argv[0] = argv[2]; - argv[2] = NULL; - } else { - /* "busybox <applet> arg1 arg2 ..." */ - argv++; - } - /* We support "busybox /a/path/to/applet args..." too. Allows for - * "#!/bin/busybox"-style wrappers */ - applet_name = bb_get_last_path_component_nostrip(argv[0]); - run_applet_and_exit(applet_name, argv); - bb_error_msg_and_die("applet not found"); -} - -void run_appletstruct_and_exit(const struct bb_applet *applet, char **argv) -{ - int argc = 1; - - while (argv[argc]) - argc++; - - /* Reinit some shared global data */ - optind = 1; - xfunc_error_retval = EXIT_FAILURE; - - applet_name = applet->name; - if (argc == 2 && !strcmp(argv[1], "--help")) - bb_show_usage(); - if (ENABLE_FEATURE_SUID) - check_suid(applet); - exit(applet->main(argc, argv)); -} - -void run_applet_and_exit(const char *name, char **argv) -{ - const struct bb_applet *applet = find_applet_by_name(name); - if (applet) - run_appletstruct_and_exit(applet, argv); - if (!strncmp(name, "busybox", 7)) - exit(busybox_main(argv)); -} - - +#if ENABLE_BUILD_LIBBUSYBOX int main(int argc, char **argv) { - bbox_prepare_main(argv); - -#if !BB_MMU - /* NOMMU re-exec trick sets high-order bit in first byte of name */ - if (argv[0][0] & 0x80) { - re_execed = 1; - argv[0][0] &= 0x7f; - } -#endif - applet_name = argv[0]; - if (applet_name[0] == '-') - applet_name++; - applet_name = bb_basename(applet_name); - - parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */ - - run_applet_and_exit(applet_name, argv); - bb_error_msg_and_die("applet not found"); + return libbusybox_main(argc, argv); } +#endif |