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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:46:30 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:46:30 +0000
commitb5896ba9f6047e7031e2bdee0622d543e11a6734 (patch)
treefd7b460593a2fee1be579bec5697e6d887ea3421 /src/util/chroot_uid.c
parentInitial commit. (diff)
downloadpostfix-b5896ba9f6047e7031e2bdee0622d543e11a6734.tar.xz
postfix-b5896ba9f6047e7031e2bdee0622d543e11a6734.zip
Adding upstream version 3.4.23.upstream/3.4.23upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/util/chroot_uid.c')
-rw-r--r--src/util/chroot_uid.c88
1 files changed, 88 insertions, 0 deletions
diff --git a/src/util/chroot_uid.c b/src/util/chroot_uid.c
new file mode 100644
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--- /dev/null
+++ b/src/util/chroot_uid.c
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+/*++
+/* NAME
+/* chroot_uid 3
+/* SUMMARY
+/* limit possible damage a process can do
+/* SYNOPSIS
+/* #include <chroot_uid.h>
+/*
+/* void chroot_uid(root_dir, user_name)
+/* const char *root_dir;
+/* const char *user_name;
+/* DESCRIPTION
+/* \fBchroot_uid\fR changes the process root to \fIroot_dir\fR and
+/* changes process privileges to those of \fIuser_name\fR.
+/* DIAGNOSTICS
+/* System call errors are reported via the msg(3) interface.
+/* All errors are fatal.
+/* LICENSE
+/* .ad
+/* .fi
+/* The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/* Wietse Venema
+/* IBM T.J. Watson Research
+/* P.O. Box 704
+/* Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <pwd.h>
+#include <unistd.h>
+#include <grp.h>
+
+/* Utility library. */
+
+#include "msg.h"
+#include "chroot_uid.h"
+
+/* chroot_uid - restrict the damage that this program can do */
+
+void chroot_uid(const char *root_dir, const char *user_name)
+{
+ struct passwd *pwd;
+ uid_t uid;
+ gid_t gid;
+
+ /*
+ * Look up the uid/gid before entering the jail, and save them so they
+ * can't be clobbered. Set up the primary and secondary groups.
+ */
+ if (user_name != 0) {
+ if ((pwd = getpwnam(user_name)) == 0)
+ msg_fatal("unknown user: %s", user_name);
+ uid = pwd->pw_uid;
+ gid = pwd->pw_gid;
+ if (setgid(gid) < 0)
+ msg_fatal("setgid(%ld): %m", (long) gid);
+ if (initgroups(user_name, gid) < 0)
+ msg_fatal("initgroups: %m");
+ }
+
+ /*
+ * Enter the jail.
+ */
+ if (root_dir) {
+ if (chroot(root_dir))
+ msg_fatal("chroot(%s): %m", root_dir);
+ if (chdir("/"))
+ msg_fatal("chdir(/): %m");
+ }
+
+ /*
+ * Drop the user privileges.
+ */
+ if (user_name != 0)
+ if (setuid(uid) < 0)
+ msg_fatal("setuid(%ld): %m", (long) uid);
+
+ /*
+ * Give the desperate developer a clue of what is happening.
+ */
+ if (msg_verbose > 1)
+ msg_info("chroot %s user %s",
+ root_dir ? root_dir : "(none)",
+ user_name ? user_name : "(none)");
+}