1 files changed, 512 insertions, 0 deletions

diff --git a/busybox/applets/applets.c b/busybox/applets/applets.c
new file mode 100644
index 000000000..9db16b41d
--- /dev/null
+++ b/busybox/applets/applets.c
@@ -0,0 +1,512 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Utility routines.
+ *
+ * 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.
+ *
+ * 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
+ * Permission has been granted to redistribute this code under the GPL.
+ *
+ */
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include "busybox.h"
+
+const char usage_messages[] =
+
+#define MAKE_USAGE
+#include "usage.h"
+
+#include "applets.h"
+
+;
+
+#undef MAKE_USAGE
+#undef APPLET
+#undef APPLET_NOUSAGE
+#undef PROTOTYPES
+#include "applets.h"
+
+
+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);
+
+
+#ifdef CONFIG_FEATURE_SUID
+
+static void check_suid (struct BB_applet *app);
+
+#ifdef CONFIG_FEATURE_SUID_CONFIG
+
+#include <sys/stat.h>
+#include <ctype.h>
+#include "pwd_.h"
+#include "grp_.h"
+
+static void parse_config_file (void);
+
+#define CONFIG_FILE "/etc/busybox.conf"
+
+/* applets [] is const, so we have to define this "override" structure */
+struct BB_suid_config
+{
+  struct BB_applet *m_applet;
+
+  uid_t m_uid;
+  gid_t m_gid;
+  mode_t m_mode;
+
+  struct BB_suid_config *m_next;
+};
+
+static struct BB_suid_config *suid_config;
+static int suid_cfg_readable;
+
+#endif /* CONFIG_FEATURE_SUID_CONFIG */
+
+#endif /* CONFIG_FEATURE_SUID */
+
+
+
+extern void
+bb_show_usage (void)
+{
+  const char *format_string;
+  const char *usage_string = 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 (EXIT_FAILURE);
+}
+
+static int
+applet_name_compare (const void *x, const void *y)
+{
+  const char *name = x;
+  const struct BB_applet *applet = y;
+
+  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);
+}
+
+void
+run_applet_by_name (const char *name, int argc, char **argv)
+{
+  static int recurse_level = 0;
+  extern int been_there_done_that;      /* From busybox.c */
+
+#ifdef CONFIG_FEATURE_SUID_CONFIG
+  if (recurse_level == 0)
+        parse_config_file ();
+#endif
+
+  recurse_level++;
+  /* Do a binary search to find the applet entry given the name. */
+  if ((applet_using = find_applet_by_name (name)) != NULL) {
+        bb_applet_name = applet_using->name;
+        if (argv[1] && strcmp (argv[1], "--help") == 0) {
+          if (strcmp (applet_using->name, "busybox") == 0) {
+                if (argv[2])
+                  applet_using = find_applet_by_name (argv[2]);
+                else
+                  applet_using = NULL;
+          }
+          if (applet_using)
+                bb_show_usage ();
+          been_there_done_that = 1;
+          busybox_main (0, NULL);
+        }
+#ifdef CONFIG_FEATURE_SUID
+        check_suid (applet_using);
+#endif
+
+        exit ((*(applet_using->main)) (argc, argv));
+  }
+  /* Just in case they have renamed busybox - Check argv[1] */
+  if (recurse_level == 1) {
+        run_applet_by_name ("busybox", argc, argv);
+  }
+  recurse_level--;
+}
+
+
+#ifdef CONFIG_FEATURE_SUID
+
+#ifdef CONFIG_FEATURE_SUID_CONFIG
+
+/* 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;
+}
+
+#endif
+
+
+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 */
+                if (setegid (sct->m_gid))
+                  bb_error_msg_and_die
+                        ("BusyBox binary has insufficient rights to set proper GID for applet!");
+          } else
+                setgid (rgid);                  /* no sgid -> drop */
+
+          if (sct->m_mode & S_ISUID) {
+                if (seteuid (sct->m_uid))
+                  bb_error_msg_and_die
+                        ("BusyBox binary has insufficient rights to set proper UID for applet!");
+          } else
+                setuid (ruid);                  /* no suid -> drop */
+        } else {
+                /* default: drop all priviledges */
+          setgid (rgid);
+          setuid (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 () != 0)
+          bb_error_msg_and_die ("This applet requires root priviledges!");
+  } else if (applet->need_suid == _BB_SUID_NEVER) {
+        setgid (rgid);                          /* drop all priviledges */
+        setuid (ruid);
+  }
+}
+
+#ifdef CONFIG_FEATURE_SUID_CONFIG
+
+/* 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 (char *) bb_skip_whitespace(s);
+}
+
+
+#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)
+{
+        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 = (char *) bb_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 = (char *) bb_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;
+
+                                        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;
+}
+
+#endif
+
+#endif
+
+/* END CODE */
+/*
+  Local Variables:
+  c-file-style: "linux"
+  c-basic-offset: 4
+  tab-width: 4
+End:
+*/