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authorchristos <christos@NetBSD.org>2003-02-26 18:16:50 +0000
committerchristos <christos@NetBSD.org>2003-02-26 18:16:50 +0000
commitdc7c6aef2a2604d14297736229006b40e742e2f2 (patch)
tree924b6feff5c9fe76e7e8c1f634d821912883fc59 /libexec
parente651d04ed9ac80b580557e94079ce119e3064c88 (diff)
The following changes make ftpd able to remove its own entries. Ftpd
calls pututxline() with ruid = 0, euid = current-ftp-user. This ends up calling update_utmp: - if the real uid is root, don't do password or tty ownership checks - if we cannot open the tty line, assume that it is a daemon that does not use ttys and allow it to change a live entry to a dead one if indeed it is the same process that created the entry.
Diffstat (limited to 'libexec')
-rw-r--r--libexec/utmp_update/utmp_update.c60
1 files changed, 39 insertions, 21 deletions
diff --git a/libexec/utmp_update/utmp_update.c b/libexec/utmp_update/utmp_update.c
index b41f09e62c8..89b6c2b3633 100644
--- a/libexec/utmp_update/utmp_update.c
+++ b/libexec/utmp_update/utmp_update.c
@@ -1,4 +1,4 @@
-/* $NetBSD: utmp_update.c,v 1.5 2002/12/18 15:20:47 christos Exp $ */
+/* $NetBSD: utmp_update.c,v 1.6 2003/02/26 18:16:50 christos Exp $ */
/*-
* Copyright (c) 2002 The NetBSD Foundation, Inc.
@@ -37,7 +37,7 @@
*/
#include <sys/cdefs.h>
-__RCSID("$NetBSD: utmp_update.c,v 1.5 2002/12/18 15:20:47 christos Exp $");
+__RCSID("$NetBSD: utmp_update.c,v 1.6 2003/02/26 18:16:50 christos Exp $");
#include <sys/types.h>
#include <sys/param.h>
@@ -64,11 +64,12 @@ main(int argc, char *argv[])
struct passwd *pwd;
struct stat st;
int fd;
- uid_t euid;
+ uid_t euid, ruid;
char tty[MAXPATHLEN];
euid = geteuid();
- if (seteuid(getuid()) == -1)
+ ruid = getuid();
+ if (seteuid(ruid) == -1)
err(1, "seteuid");
if (argc != 2) {
@@ -96,27 +97,44 @@ main(int argc, char *argv[])
errx(1, "Invalid utmpx type %d", (int)utx->ut_type);
}
- if ((pwd = getpwuid(getuid())) == NULL)
- errx(1, "User %lu does not exist in password database",
- (long)getuid());
+ if (ruid != 0) {
+ if ((pwd = getpwuid(ruid)) == NULL)
+ errx(1, "User %lu does not exist in password database",
+ (long)ruid);
- if (strcmp(pwd->pw_name, utx->ut_name) != 0)
- errx(1, "Current user `%s' does not match `%s' in utmpx entry",
- pwd->pw_name, utx->ut_name);
+ if (strcmp(pwd->pw_name, utx->ut_name) != 0)
+ errx(1, "Current user `%s' does not match "
+ "`%s' in utmpx entry", pwd->pw_name, utx->ut_name);
+ }
(void)snprintf(tty, sizeof(tty), "%s%s", _PATH_DEV, utx->ut_line);
fd = open(tty, O_RDONLY, 0);
- if (fd == -1)
- err(1, "Cannot open `%s'", tty);
- if (fstat(fd, &st) == -1)
- err(1, "Cannot stat `%s'", tty);
- if (st.st_uid != getuid())
- errx(1, "%s: Is not owned by you", tty);
- if (!isatty(fd))
- errx(1, "%s: Not a tty device", tty);
- (void)close(fd);
- if (access(tty, W_OK|R_OK) == -1)
- err(1, "%s", tty);
+ if (fd != -1) {
+ if (fstat(fd, &st) == -1)
+ err(1, "Cannot stat `%s'", tty);
+ if (ruid != 0 && st.st_uid != ruid)
+ errx(1, "%s: Is not owned by you", tty);
+ if (!isatty(fd))
+ errx(1, "%s: Not a tty device", tty);
+ (void)close(fd);
+ if (access(tty, W_OK|R_OK) == -1)
+ err(1, "%s", tty);
+ } else {
+ struct utmpx utold, *utoldp;
+ /*
+ * A daemon like ftpd that does not use a tty line?
+ * We only allow it to kill its own existing entries
+ */
+ if (utx->ut_type != DEAD_PROCESS)
+ err(1, "Cannot open `%s'", tty);
+
+ (void)memcpy(utold.ut_line, utx->ut_line, sizeof(utx->ut_line));
+ if ((utoldp = getutxline(&utold)) == NULL)
+ err(1, "Cannot find existing entry for `%s'",
+ utx->ut_line);
+ if (utoldp->ut_pid != getppid())
+ err(1, "Cannot modify entry for `%s'", tty);
+ }
(void)seteuid(euid);
if (pututxline(utx) == NULL)