Add checks for realpath(3) and a version from NetBSD for those without it.

MANIFEST

@@ -276,6 +276,7 @@ lib/util/pw_dup.c
 lib/util/pwrite.c
 lib/util/rcstr.c
 lib/util/reallocarray.c
+lib/util/realpath.c
 lib/util/regex.c
 lib/util/regress/closefrom/closefrom_test.c
 lib/util/regress/corpus/seed/sudo_conf/sudo.conf.1

config.h.in

@@ -207,6 +207,10 @@
    don't. */
 #undef HAVE_DECL_SSIZE_MAX
 
+/* Define to 1 if you have the declaration of 'SYMLOOP_MAX', and to 0 if you
+   don't. */
+#undef HAVE_DECL_SYMLOOP_MAX
+
 /* Define to 1 if you have the declaration of 'sys_sigabbrev', and to 0 if you
    don't. */
 #undef HAVE_DECL_SYS_SIGABBREV
@@ -243,6 +247,10 @@
    you don't. */
 #undef HAVE_DECL__POSIX_PATH_MAX
 
+/* Define to 1 if you have the declaration of '_POSIX_SYMLOOP_MAX', and to 0
+   if you don't. */
+#undef HAVE_DECL__POSIX_SYMLOOP_MAX
+
 /* Define to 1 if you have the declaration of '_sys_siglist', and to 0 if you
    don't. */
 #undef HAVE_DECL__SYS_SIGLIST
@@ -758,6 +766,9 @@
 /* Define to 1 if you have the 'reallocarray' function. */
 #undef HAVE_REALLOCARRAY
 
+/* Define to 1 if you have the 'realpath' function. */
+#undef HAVE_REALPATH
+
 /* Define to 1 if you have the 'revoke' function. */
 #undef HAVE_REVOKE
 

configure

@@ -23692,6 +23692,33 @@ esac
 esac
 fi
 
+done
+
+  for ac_func in realpath
+do :
+  ac_fn_c_check_func "$LINENO" "realpath" "ac_cv_func_realpath"
+if test "x$ac_cv_func_realpath" = xyes
+then :
+  printf "%s\n" "#define HAVE_REALPATH 1" >>confdefs.h
+
+else case e in #(
+  e)
+    case " $LIBOBJS " in
+  *" realpath.$ac_objext "* ) ;;
+  *) LIBOBJS="$LIBOBJS realpath.$ac_objext"
+ ;;
+esac
+
+
+    for _sym in sudo_realpath; do
+	COMPAT_EXP="${COMPAT_EXP}${_sym}
+"
+    done
+
+ ;;
+esac
+fi
+
 done
 
   for ac_func in strlcpy
@@ -28018,6 +28045,19 @@ else case e in #(
 esac
 fi
 printf "%s\n" "#define HAVE_DECL_SSIZE_MAX $ac_have_decl" >>confdefs.h
+ac_fn_check_decl "$LINENO" "SYMLOOP_MAX" "ac_cv_have_decl_SYMLOOP_MAX" "
+#include <sys/types.h>
+#include <limits.h>
+
+" "$ac_c_undeclared_builtin_options" "CFLAGS"
+if test "x$ac_cv_have_decl_SYMLOOP_MAX" = xyes
+then :
+  ac_have_decl=1
+else case e in #(
+  e) ac_have_decl=0 ;;
+esac
+fi
+printf "%s\n" "#define HAVE_DECL_SYMLOOP_MAX $ac_have_decl" >>confdefs.h
 
 ac_fn_check_decl "$LINENO" "SIZE_MAX" "ac_cv_have_decl_SIZE_MAX" "
 #include <sys/types.h>
@@ -28132,6 +28172,25 @@ fi
 printf "%s\n" "#define HAVE_DECL__POSIX_PATH_MAX $ac_have_decl" >>confdefs.h
 
 
+fi
+if test "$ac_cv_have_decl_SYMLOOP_MAX" != "yes"
+then :
+
+    ac_fn_check_decl "$LINENO" "_POSIX_SYMLOOP_MAX" "ac_cv_have_decl__POSIX_SYMLOOP_MAX" "
+#include <sys/types.h>
+#include <limits.h>
+
+" "$ac_c_undeclared_builtin_options" "CFLAGS"
+if test "x$ac_cv_have_decl__POSIX_SYMLOOP_MAX" = xyes
+then :
+  ac_have_decl=1
+else case e in #(
+  e) ac_have_decl=0 ;;
+esac
+fi
+printf "%s\n" "#define HAVE_DECL__POSIX_SYMLOOP_MAX $ac_have_decl" >>confdefs.h
+
+
 fi
 
 

configure.ac

@@ -2884,6 +2884,10 @@ AC_CHECK_FUNCS([pw_dup], [], [
     AC_LIBOBJ(pw_dup)
     SUDO_APPEND_COMPAT_EXP(sudo_pw_dup)
 ])
+AC_CHECK_FUNCS([realpath], [], [
+    AC_LIBOBJ(realpath)
+    SUDO_APPEND_COMPAT_EXP(sudo_realpath)
+])
 AC_CHECK_FUNCS([strlcpy], [], [
     AC_LIBOBJ(strlcpy)
     SUDO_APPEND_COMPAT_EXP(sudo_strlcpy)
@@ -3275,7 +3279,7 @@ AC_INCLUDES_DEFAULT
 dnl
 dnl Check for incomplete limits.h and missing SIZE_MAX.
 dnl
-AC_CHECK_DECLS([LLONG_MAX, LLONG_MIN, ULLONG_MAX, PATH_MAX, SSIZE_MAX], [], [], [
+AC_CHECK_DECLS([LLONG_MAX, LLONG_MIN, ULLONG_MAX, PATH_MAX, SSIZE_MAX, SYMLOOP_MAX], [], [], [
 #include <sys/types.h>
 #include <limits.h>
 ])
@@ -3321,6 +3325,12 @@ AS_IF([test "$ac_cv_have_decl_PATH_MAX" != "yes"], [
 #include <limits.h>
     ]])
 ])
+AS_IF([test "$ac_cv_have_decl_SYMLOOP_MAX" != "yes"], [
+    AC_CHECK_DECLS([_POSIX_SYMLOOP_MAX], [], [], [[
+#include <sys/types.h>
+#include <limits.h>
+    ]])
+])
 
 dnl
 dnl Check for strsignal() or sys_siglist

include/sudo_compat.h

@@ -103,6 +103,14 @@
 # endif
 #endif
 
+#if defined(HAVE_DECL_SYMLOOP_MAX) && !HAVE_DECL_SYMLOOP_MAX
+# if defined(HAVE_DECL__POSIX_SYMLOOP_MAX) && HAVE_DECL__POSIX_SYMLOOP_MAX
+#  define SYMLOOP_MAX		_POSIX_SYMLOOP_MAX
+# else
+#  define SYMLOOP_MAX		8
+# endif
+#endif
+
 /* ACCESSPERMS and ALLPERMS are handy BSDisms. */
 #ifndef ACCESSPERMS
 # define ACCESSPERMS	00777
@@ -552,6 +560,11 @@ sudo_dso_public void *sudo_reallocarray(void *ptr, size_t nmemb, size_t size);
 # undef reallocarray
 # define reallocarray(_a, _b, _c) sudo_reallocarray((_a), (_b), (_c))
 #endif /* HAVE_REALLOCARRAY */
+#ifndef HAVE_REALPATH
+sudo_dso_public void *sudo_realpath(const char *path, char *resolved);
+# undef realpath
+# define realpath(_a, _b) sudo_realpath((_a), (_b))
+#endif /* HAVE_REALPATH */
 #ifndef HAVE_DUP3
 sudo_dso_public int sudo_dup3(int oldd, int newd, int flags);
 # undef dup3

lib/util/Makefile.in

@@ -1041,11 +1041,11 @@ key_val.plog: key_val.i
 	rm -f $@; pvs-studio --cfg $(PVS_CFG) --sourcetree-root $(top_srcdir) --skip-cl-exe yes --source-file $(srcdir)/key_val.c --i-file $< --output-file $@
 lbuf.lo: $(srcdir)/lbuf.c $(incdir)/compat/stdbool.h $(incdir)/sudo_compat.h \
          $(incdir)/sudo_debug.h $(incdir)/sudo_lbuf.h $(incdir)/sudo_queue.h \
-         $(top_builddir)/config.h
+         $(incdir)/sudo_util.h $(top_builddir)/config.h
 	$(LIBTOOL) $(LTFLAGS) --mode=compile $(CC) -c -o $@ $(CPPFLAGS) $(CFLAGS) $(ASAN_CFLAGS) $(PIE_CFLAGS) $(HARDENING_CFLAGS) $(srcdir)/lbuf.c
 lbuf.i: $(srcdir)/lbuf.c $(incdir)/compat/stdbool.h $(incdir)/sudo_compat.h \
          $(incdir)/sudo_debug.h $(incdir)/sudo_lbuf.h $(incdir)/sudo_queue.h \
-         $(top_builddir)/config.h
+         $(incdir)/sudo_util.h $(top_builddir)/config.h
 	$(CC) -E -o $@ $(CPPFLAGS) $<
 lbuf.plog: lbuf.i
 	rm -f $@; pvs-studio --cfg $(PVS_CFG) --sourcetree-root $(top_srcdir) --skip-cl-exe yes --source-file $(srcdir)/lbuf.c --i-file $< --output-file $@
@@ -1311,6 +1311,12 @@ reallocarray.i: $(srcdir)/reallocarray.c $(incdir)/sudo_compat.h \
 	$(CC) -E -o $@ $(CPPFLAGS) $<
 reallocarray.plog: reallocarray.i
 	rm -f $@; pvs-studio --cfg $(PVS_CFG) --sourcetree-root $(top_srcdir) --skip-cl-exe yes --source-file $(srcdir)/reallocarray.c --i-file $< --output-file $@
+realpath.lo: $(srcdir)/realpath.c $(top_builddir)/config.h
+	$(LIBTOOL) $(LTFLAGS) --mode=compile $(CC) -c -o $@ $(CPPFLAGS) $(CFLAGS) $(ASAN_CFLAGS) $(PIE_CFLAGS) $(HARDENING_CFLAGS) $(srcdir)/realpath.c
+realpath.i: $(srcdir)/realpath.c $(top_builddir)/config.h
+	$(CC) -E -o $@ $(CPPFLAGS) $<
+realpath.plog: realpath.i
+	rm -f $@; pvs-studio --cfg $(PVS_CFG) --sourcetree-root $(top_srcdir) --skip-cl-exe yes --source-file $(srcdir)/realpath.c --i-file $< --output-file $@
 regex.lo: $(srcdir)/regex.c $(incdir)/compat/stdbool.h $(incdir)/sudo_compat.h \
           $(incdir)/sudo_debug.h $(incdir)/sudo_gettext.h \
           $(incdir)/sudo_queue.h $(incdir)/sudo_util.h $(top_builddir)/config.h

lib/util/realpath.c

@@ -0,0 +1,198 @@
+/*
+ * Copyright (c) 1989, 1991, 1993, 1995
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Jan-Simon Pendry.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)getcwd.c	8.5 (Berkeley) 2/7/95
+ */
+
+#include <config.h>
+
+#ifndef HAVE_REALPATH
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+/*
+ * char *realpath(const char *path, char *resolved);
+ *
+ * Find the real name of path, by removing all ".", ".." and symlink
+ * components.  Returns (resolved) on success, or (NULL) on failure,
+ * in which case the path which caused trouble is left in (resolved).
+ */
+char *
+sudo_realpath(const char *path, char *resolved)
+{
+	struct stat sb;
+	int idx = 0, nlnk = 0;
+	const char *q;
+	char *p, wbuf[2][PATH_MAX], *fres = NULL;
+	size_t len;
+	ssize_t n;
+
+	if (path == NULL) {
+		errno = EINVAL;
+		return NULL;
+	}
+
+	if (resolved == NULL) {
+		fres = resolved = malloc(PATH_MAX);
+		if (resolved == NULL)
+			return NULL;
+	}
+
+
+	/*
+	 * Build real path one by one with paying an attention to .,
+	 * .. and symbolic link.
+	 */
+
+	/*
+	 * `p' is where we'll put a new component with prepending
+	 * a delimiter.
+	 */
+	p = resolved;
+
+	if (*path == '\0') {
+		*p = '\0';
+		errno = ENOENT;
+		goto out;
+	}
+
+	/* If relative path, start from current working directory. */
+	if (*path != '/') {
+		if (getcwd(resolved, PATH_MAX) == NULL) {
+			p[0] = '.';
+			p[1] = '\0';
+			goto out;
+		}
+		len = strlen(resolved);
+		if (len > 1)
+			p += len;
+	}
+
+loop:
+	/* Skip any slash. */
+	while (*path == '/')
+		path++;
+
+	if (*path == '\0') {
+		if (p == resolved)
+			*p++ = '/';
+		*p = '\0';
+		return resolved;
+	}
+
+	/* Find the end of this component. */
+	q = path;
+	do {
+		q++;
+	} while (*q != '/' && *q != '\0');
+
+	/* Test . or .. */
+	if (path[0] == '.') {
+		if (q - path == 1) {
+			path = q;
+			goto loop;
+		}
+		if (path[1] == '.' && q - path == 2) {
+			/* Trim the last component. */
+			if (p != resolved)
+				while (*--p != '/')
+					continue;
+			path = q;
+			goto loop;
+		}
+	}
+
+	/* Append this component. */
+	if (p - resolved + 1 + q - path + 1 > PATH_MAX) {
+		errno = ENAMETOOLONG;
+		if (p == resolved)
+			*p++ = '/';
+		*p = '\0';
+		goto out;
+	}
+	p[0] = '/';
+	memcpy(&p[1], path, q - path);
+	p[1 + q - path] = '\0';
+
+	/*
+	 * If this component is a symlink, toss it and prepend link
+	 * target to unresolved path.
+	 */
+	if (lstat(resolved, &sb) == -1)
+		goto out;
+
+	if (S_ISLNK(sb.st_mode)) {
+		if (nlnk++ >= SYMLOOP_MAX) {
+			errno = ELOOP;
+			goto out;
+		}
+		n = readlink(resolved, wbuf[idx], sizeof(wbuf[0]) - 1);
+		if (n < 0)
+			goto out;
+		if (n == 0) {
+			errno = ENOENT;
+			goto out;
+		}
+
+		/* Append unresolved path to link target and switch to it. */
+		if (n + (len = strlen(q)) + 1 > sizeof(wbuf[0])) {
+			errno = ENAMETOOLONG;
+			goto out;
+		}
+		memcpy(&wbuf[idx][n], q, len + 1);
+		path = wbuf[idx];
+		idx ^= 1;
+
+		/* If absolute symlink, start from root. */
+		if (*path == '/')
+			p = resolved;
+		goto loop;
+	}
+	if (*q == '/' && !S_ISDIR(sb.st_mode)) {
+		errno = ENOTDIR;
+		goto out;
+	}
+
+	/* Advance both resolved and unresolved path. */
+	p += 1 + q - path;
+	path = q;
+	goto loop;
+out:
+	free(fres);
+	return NULL;
+}
+#endif /* HAVE_REALPATH */

scripts/mkdep.pl

@@ -120,7 +120,7 @@ sub mkdep {
     # XXX - fill in AUTH_OBJS from contents of the auth dir instead
     $makefile =~ s:\@AUTH_OBJS\@:afs.lo aix_auth.lo bsdauth.lo dce.lo fwtk.lo getspwuid.lo kerb5.lo pam.lo passwd.lo rfc1938.lo secureware.lo securid5.lo sia.lo:;
     $makefile =~ s:\@DIGEST\@:digest.lo digest_openssl.lo digest_gcrypt.lo:;
-    $makefile =~ s:\@LTLIBOBJS\@:arc4random.lo arc4random_buf.lo arc4random_uniform.lo cfmakeraw.lo closefrom.lo dup3.lo explicit_bzero.lo fchmodat.lo fchownat.lo freezero.lo fstatat.lo fnmatch.lo getaddrinfo.lo getcwd.lo getentropy.lo getgrouplist.lo getdelim.lo getopt_long.lo getusershell.lo glob.lo gmtime_r.lo inet_ntop_lo inet_pton.lo isblank.lo localtime_r.lo memrchr.lo mkdirat.lo mksiglist.lo mksigname.lo mktemp.lo nanosleep.lo openat.lo pipe2.lo pread.lo pwrite.lo pw_dup.lo reallocarray.lo sha2.lo sig2str.lo siglist.lo signame.lo snprintf.lo str2sig.lo strlcat.lo strlcpy.lo strndup.lo strnlen.lo strsignal.lo timegm.lo unlinkat.lo utimens.lo:;
+    $makefile =~ s:\@LTLIBOBJS\@:arc4random.lo arc4random_buf.lo arc4random_uniform.lo cfmakeraw.lo closefrom.lo dup3.lo explicit_bzero.lo fchmodat.lo fchownat.lo freezero.lo fstatat.lo fnmatch.lo getaddrinfo.lo getcwd.lo getentropy.lo getgrouplist.lo getdelim.lo getopt_long.lo getusershell.lo glob.lo gmtime_r.lo inet_ntop_lo inet_pton.lo isblank.lo localtime_r.lo memrchr.lo mkdirat.lo mksiglist.lo mksigname.lo mktemp.lo nanosleep.lo openat.lo pipe2.lo pread.lo pwrite.lo pw_dup.lo reallocarray.lo realpath.lo sha2.lo sig2str.lo siglist.lo signame.lo snprintf.lo str2sig.lo strlcat.lo strlcpy.lo strndup.lo strnlen.lo strsignal.lo timegm.lo unlinkat.lo utimens.lo:;
 
     # Parse OBJS lines
     my %objs;