* isn't something I'm going to worry about... If you wrote something
* here, please feel free to acknowledge your work.
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- *
- * Based in part on code from sash, Copyright (c) 1999 by David I. Bell
+ * 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.
*/
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
#include "busybox.h"
+#include <unistd.h>
+#include <string.h>
+#include <assert.h>
+
+#if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
+static const char usage_messages[] =
+#define MAKE_USAGE
+#include "usage.h"
+#include "applets.h"
+;
+#undef MAKE_USAGE
+#else
+#define usage_messages 0
+#endif /* ENABLE_SHOW_USAGE */
#undef APPLET
#undef APPLET_NOUSAGE
#undef PROTOTYPES
#include "applets.h"
-struct BB_applet *applet_using;
+static struct BB_applet *applet_using;
/* The -1 arises because of the {0,NULL,0,-1} entry above. */
const size_t NUM_APPLETS = (sizeof (applets) / sizeof (struct BB_applet) - 1);
-extern void show_usage(void)
+
+#ifdef CONFIG_FEATURE_SUID_CONFIG
+
+#include <ctype.h>
+#include "pwd_.h"
+#include "grp_.h"
+
+#define CONFIG_FILE "/etc/busybox.conf"
+
+/* applets [] is const, so we have to define this "override" structure */
+static struct BB_suid_config
{
- const char *format_string;
- const char *usage_string = usage_messages;
- int i;
- /* From busybox.c */
- extern int been_there_done_that;
-
- if (strcmp(applet_using->name, "busybox")==0) {
- been_there_done_that=1;
- busybox_main(0, NULL);
+ 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 int 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;
+}
- for (i = applet_using - applets; i > 0; ) {
- if (!*usage_string++) {
- --i;
+/* 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;
}
}
- format_string = "%s\n\nUsage: %s %s\n\n";
- if(*usage_string == 0)
- format_string = "%s\n\nNo help available.\n\n";
- fprintf(stderr, format_string,
- full_version, applet_using->name, usage_string);
- exit(EXIT_FAILURE);
+ 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);
}
-static int applet_name_compare(const void *x, const void *y)
+
+#define parse_error(x) { err=x; goto pe_label; }
+
+/* Don't depend on the tools to combine strings. */
+static const char config_file[] = CONFIG_FILE;
+
+/* There are 4 chars + 1 nul for each of user/group/other. */
+static const char mode_chars[] = "Ssx-\0Ssx-\0Ttx-";
+
+/* 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[] = {
+ /* 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 */
+};
+
+static void parse_config_file(void)
{
- const char *name = x;
- const struct BB_applet *applet = y;
+ struct BB_suid_config *sct_head;
+ struct BB_suid_config *sct;
+ struct BB_applet *applet;
+ FILE *f;
+ char *err;
+ char *s;
+ char *e;
+ int i, lc, section;
+ char buffer[256];
+ struct stat st;
+
+ assert(!suid_config); /* Should be set to NULL by bss init. */
+
+ 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")) /* Can not open? */
+ ) {
+ return;
+ }
+
+ suid_cfg_readable = 1;
+ sct_head = NULL;
+ section = lc = 0;
+
+ do {
+ 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. */
+ if (!*(s = get_trimmed_slice(s, strchrnul(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. */
+ if (!(e = strchr(s, ']')) /* 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). */
+ if (!!(e = strchr(s, '='))) {
+ 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. */
+ if ((applet = find_applet_by_name(s))) {
+ /* 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++) {
+ const char *q;
+ if (!*(q = strchrnul(mode_chars + 5*i, *e++))) {
+ 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... */
+ {
+ char *e2;
- return strcmp(name, applet->name);
+ sct->m_uid = strtoul(s, &e2, 10);
+ if (*e2 || (s == e2)) {
+ struct passwd *pwd;
+ if (!(pwd = getpwnam(s))) {
+ parse_error("user");
+ }
+ sct->m_uid = pwd->pw_uid;
+ }
+
+ sct->m_gid = strtoul(e, &e2, 10);
+ if (*e2 || (e == e2)) {
+ struct group *grp;
+ if (!(grp = getgrnam(e))) {
+ 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, err);
+
+ fclose(f);
+ /* Release any allocated memory before returning. */
+ while (sct_head) {
+ sct = sct_head->m_next;
+ free(sct_head);
+ sct_head = sct;
+ }
+ return;
}
-extern size_t NUM_APPLETS;
+#else
+#define parse_config_file()
+#endif /* CONFIG_FEATURE_SUID_CONFIG */
+
+#ifdef CONFIG_FEATURE_SUID
+static void check_suid (struct BB_applet *applet)
+{
+ uid_t ruid = getuid (); /* real [ug]id */
+ uid_t rgid = getgid ();
+
+#ifdef CONFIG_FEATURE_SUID_CONFIG
+ if (suid_cfg_readable) {
+ struct BB_suid_config *sct;
+
+ for (sct = suid_config; sct; sct = sct->m_next) {
+ if (sct->m_applet == applet)
+ break;
+ }
+ if (sct) {
+ mode_t 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!");
+
+ if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { /* *both* have to be set for sgid */
+ xsetgid(sct->m_gid);
+ } else xsetgid(rgid); /* no sgid -> drop */
+
+ if (sct->m_mode & S_ISUID) xsetuid(sct->m_uid);
+ else xsetuid(ruid); /* no suid -> drop */
+ } else {
+ /* default: drop all privileges */
+ xsetgid(rgid);
+ xsetuid(ruid);
+ }
+ return;
+ } else {
+#ifndef CONFIG_FEATURE_SUID_CONFIG_QUIET
+ static int onetime = 0;
+
+ if (!onetime) {
+ onetime = 1;
+ fprintf (stderr, "Using fallback suid method\n");
+ }
+#endif
+ }
+#endif
+
+ if (applet->need_suid == _BB_SUID_ALWAYS) {
+ 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)
+#endif /* CONFIG_FEATURE_SUID */
+
+
+
+#if ENABLE_FEATURE_COMPRESS_USAGE
+
+#include "usage_compressed.h"
+#include "unarchive.h"
+
+static const char *unpack_usage_messages(void)
+{
+ int input[2], output[2], pid;
+ char *buf;
+
+ if(pipe(input) < 0 || pipe(output) < 0)
+ exit(1);
+
+ pid = fork();
+ switch (pid) {
+ case -1: /* error */
+ exit(1);
+ case 0: /* child */
+ close(input[1]);
+ close(output[0]);
+ uncompressStream(input[0], output[1]);
+ exit(0);
+ }
+ /* parent */
+
+ close(input[0]);
+ close(output[1]);
+ pid = fork();
+ switch (pid) {
+ case -1: /* error */
+ exit(1);
+ case 0: /* child */
+ full_write(input[1], packed_usage, sizeof(packed_usage));
+ exit(0);
+ }
+ /* parent */
+ close(input[1]);
+
+ buf = xmalloc(SIZEOF_usage_messages);
+ full_read(output[0], buf, SIZEOF_usage_messages);
+ return buf;
+}
+
+#else
+#define unpack_usage_messages() usage_messages
+#endif /* ENABLE_FEATURE_COMPRESS_USAGE */
+
+void bb_show_usage (void)
+{
+ if (ENABLE_SHOW_USAGE) {
+ const char *format_string;
+ const char *usage_string = unpack_usage_messages();
+ int i;
+
+ for (i = applet_using - applets; i > 0;)
+ if (!*usage_string++) --i;
+
+ format_string = "%s\n\nUsage: %s %s\n\n";
+ if (*usage_string == '\b')
+ format_string = "%s\n\nNo help available.\n\n";
+ fprintf (stderr, format_string, bb_msg_full_version,
+ applet_using->name, usage_string);
+ }
+
+ exit (bb_default_error_retval);
+}
+
+static int applet_name_compare(const void *name, const void *vapplet)
+{
+ const struct BB_applet *applet = vapplet;
+
+ return strcmp(name, applet->name);
+}
+
+extern const size_t NUM_APPLETS;
struct BB_applet *find_applet_by_name(const char *name)
{
- return bsearch(name, applets, NUM_APPLETS, sizeof(struct BB_applet),
- applet_name_compare);
+ return bsearch(name, applets, NUM_APPLETS, sizeof(struct BB_applet),
+ applet_name_compare);
}
void run_applet_by_name(const char *name, int argc, char **argv)
{
+ if (ENABLE_FEATURE_SUID_CONFIG) parse_config_file();
+
+ if (!strncmp(name, "busybox", 7)) busybox_main(argc, argv);
/* Do a binary search to find the applet entry given the name. */
- if ((applet_using = find_applet_by_name(name)) != NULL) {
- applet_name = applet_using->name;
- if (argv[1] && strcmp(argv[1], "--help") == 0)
- show_usage();
- exit((*(applet_using->main)) (argc, argv));
+ applet_using = find_applet_by_name(name);
+ if (applet_using) {
+ bb_applet_name = applet_using->name;
+ if(argc==2 && !strcmp(argv[1], "--help")) bb_show_usage();
+ if(ENABLE_FEATURE_SUID) check_suid(applet_using);
+ exit((*(applet_using->main))(argc, argv));
}
}
-
-
-/* END CODE */
-/*
-Local Variables:
-c-file-style: "linux"
-c-basic-offset: 4
-tab-width: 4
-End:
-*/
projects / oweals / busybox.git / blobdiff