X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=applets%2Fapplets.c;h=bd8cfec5da2356ace2e14c4b57be656cb9f47dc7;hb=eea561871b45a2335ab6a09f14dad627ffcdc1cd;hp=c1575c70d3220919ae6986f9eec3ca323fd6c385;hpb=04095e58fb4d3a083f77962714080ffe8139b39c;p=oweals%2Fbusybox.git

diff --git a/applets/applets.c b/applets/applets.c
index c1575c70d..bd8cfec5d 100644
--- a/applets/applets.c
+++ b/applets/applets.c
@@ -6,99 +6,472 @@
  * 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:
-*/