sftp-server (secure) chroot patch, comment fix

[Magnus F]

Accidently removed XXX comment. New patch below.

Regards
Magnus

--- openssh-3.6.1p2/sftp-server.c.org 2003-08-11 22:07:47.098650000 +0200
+++ openssh-3.6.1p2/sftp-server.c 2003-08-16 19:07:14.273582000 +0200
@@ -24,15 +24,24 @@
 #include "includes.h"
 RCSID("$OpenBSD: sftp-server.c,v 1.41 2003/03/26 04:02:51 deraadt Exp $");
 
+#define CHROOT
 #include "buffer.h"
 #include "bufaux.h"
 #include "getput.h"
 #include "log.h"
 #include "xmalloc.h"
-
 #include "sftp.h"
 #include "sftp-common.h"
 
+#ifdef CHROOT
+#include "uidswap.h"
+#include <pwd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <string.h>
+#include <unistd.h>
+#endif /* CHROOT */
+
 /* helper */
 #define get_int64()   buffer_get_int64(&iqueue);
 #define get_int()   buffer_get_int(&iqueue);
@@ -62,6 +71,51 @@
  Attrib attrib;
 };
 
+#ifdef CHROOT
+static void
+chroot_init(void)
+{
+ gid_t gidset[1];
+ struct passwd *pw;
+ struct stat st;
+
+ /* Sanity checking before chroot */
+ if ((pw = getpwuid(getuid())) == NULL)
+  fatal("getpwuid failed for %u", (u_int)pw->pw_uid );
+
+ /* Sets passwd pointer to null */
+        memset(pw->pw_passwd, 0, strlen(pw->pw_passwd));
+ endpwent();
+
+ if (geteuid() != 0)
+  fatal("must be SUID root to use chroot feature");
+
+ if ((stat(pw->pw_dir, &st)) == -1)
+  fatal("cannot stat chroot directory %s: %s", pw->pw_dir, strerror(errno));
+
+ if (!S_ISDIR(st.st_mode))
+  fatal("%s is not a directory: %s", pw->pw_dir, strerror(errno));
+
+ /* Drop our privileges */
+ debug3("chroot user:group %u:%u", (u_int)pw->pw_uid, (u_int)pw->pw_gid);
+
+ /* Change our root directory */
+ if (chroot(pw->pw_dir) == -1)
+  fatal("chroot(\"%s\"): %s", pw->pw_dir, strerror(errno));
+
+ /* Change dir to prevent chroot break */
+ if (chdir("/") == -1)
+  fatal("chdir(\"/\"): %s", strerror(errno));
+
+ gidset[0] = pw->pw_gid;
+ if (setgid(pw->pw_gid) < 0)
+  fatal("setgid failed for %u", (u_int)pw->pw_gid );
+ if (setgroups(1, gidset) < 0)
+  fatal("setgroups: %.100s", strerror(errno));
+ permanently_set_uid(pw);
+}
+#endif /* CHROOT */
+
 static int
 errno_to_portable(int unixerrno)
 {
@@ -1028,15 +1082,19 @@
  int in, out, max;
  ssize_t len, olen, set_size;
 
+#ifdef DEBUG_SFTP-SERVER
+ log_init("sftp-server", SYSLOG_LEVEL_DEBUG3, SYSLOG_FACILITY_AUTH, 0);
+#endif
+
+#ifdef CHROOT
+ chroot_init();
+#endif
+
  /* XXX should use getopt */
 
  __progname = get_progname(av[0]);
  handle_init();
 
-#ifdef DEBUG_SFTP_SERVER
- log_init("sftp-server", SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 0);
-#endif
-
  in = dup(STDIN_FILENO);
  out = dup(STDOUT_FILENO);