diff options
| author | christos <christos@NetBSD.org> | 2003-02-26 18:16:50 +0000 |
|---|---|---|
| committer | christos <christos@NetBSD.org> | 2003-02-26 18:16:50 +0000 |
| commit | dc7c6aef2a2604d14297736229006b40e742e2f2 (patch) | |
| tree | 924b6feff5c9fe76e7e8c1f634d821912883fc59 /libexec | |
| parent | e651d04ed9ac80b580557e94079ce119e3064c88 (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.c | 60 |
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) |
