diff options
| -rw-r--r-- | include/pathnames.h | 1 | ||||
| -rw-r--r-- | login-utils/login.c | 122 |
2 files changed, 91 insertions, 32 deletions
diff --git a/include/pathnames.h b/include/pathnames.h index 025e4afa9..1a54a037d 100644 --- a/include/pathnames.h +++ b/include/pathnames.h @@ -29,6 +29,7 @@ #define _PATH_WTMPLOCK "/etc/wtmplock" #define _PATH_HUSHLOGIN ".hushlogin" +#define _PATH_HUSHLOGINS "/etc/hushlogins" #ifndef _PATH_MAILDIR #define _PATH_MAILDIR "/var/spool/mail" diff --git a/login-utils/login.c b/login-utils/login.c index a735bc29c..38b17f5bf 100644 --- a/login-utils/login.c +++ b/login-utils/login.c @@ -566,7 +566,7 @@ static int loginpam_err(pam_handle_t * pamh, int retcode) * The open(2) seems as the surest solution. * -- kzak@redhat.com (10-Apr-2009) */ -int effective_access(const char *path, int mode) +static int effective_access(const char *path, int mode) { int fd = open(path, mode); if (fd != -1) @@ -574,6 +574,94 @@ int effective_access(const char *path, int mode) return fd == -1 ? -1 : 0; } +/* + * Check per accout or global hush-login setting. + * + * Hushed mode is enabled: + * + * a) if global (e.g. /etc/hushlogins) hush file exists: + * 1) for ALL ACCOUNTS if the file is empty + * 2) for the current user if the username or shell are found in the file + * + * b) if ~/.hushlogin file exists + * + * The ~/.hushlogin is ignored if the global hush file exists. + * + * Note that shadow-utils login(1) does not support "a1)". The "a1)" is + * necessary if you want to use PAM for "Last login" message. + * + * -- Karel Zak <kzak@redhat.com> (26-Aug-2011) + * + * + * Per-account check requires some explanation: As root we may not be able to + * read the directory of the user if it is on an NFS mounted filesystem. We + * temporarily set our effective uid to the user-uid making sure that we keep + * root privs. in the real uid. + * + * A portable solution would require a fork(), but we rely on Linux having the + * BSD setreuid() + */ +static int get_hushlogin_status(struct passwd *pwd) +{ + const char *files[] = { _PATH_HUSHLOGINS, _PATH_HUSHLOGIN, NULL }; + char buf[BUFSIZ]; + int i; + + for (i = 0; files[i]; i++) { + const char *file = files[i]; + int ok = 0; + + /* Global hush-file*/ + if (*file == '/') { + struct stat st; + FILE *f; + + if (stat(file, &st) != 0) + continue; /* file does not exist */ + + if (st.st_size == 0) + return 1; /* for all accounts */ + + f = fopen(file, "r"); + if (!f) + continue; /* ignore errors... */ + + while (ok == 0 && fgets(buf, sizeof(buf), f)) { + buf[strlen(buf) - 1] = '\0'; + ok = !strcmp(buf, *buf == '/' ? pwd->pw_shell : + pwd->pw_name); + } + fclose(f); + if (ok) + return 1; /* found username/shell */ + + return 0; /* ignore per-account files */ + } + + /* Per-account setting */ + if (strlen(pwd->pw_dir) + sizeof(file) + 2 > sizeof(buf)) + continue; + else { + uid_t ruid = getuid(); + gid_t egid = getegid(); + + sprintf(buf, "%s/%s", pwd->pw_dir, file); + setregid(-1, pwd->pw_gid); + setreuid(0, pwd->pw_uid); + ok = effective_access(buf, O_RDONLY) == 0; + setuid(0); /* setreuid doesn't do it alone! */ + setreuid(ruid, 0); + setregid(-1, egid); + + if (ok) + return 1; /* enabled by user */ + } + } + + return 0; +} + + int main(int argc, char **argv) { extern int optind; @@ -879,37 +967,7 @@ int main(int argc, char **argv) endpwent(); - { - /* - * Check per accout setting. - * - * This requires some explanation: As root we may not be able to - * read the directory of the user if it is on an NFS mounted - * filesystem. We temporarily set our effective uid to the user-uid - * making sure that we keep root privs. in the real uid. - * - * A portable solution would require a fork(), but we rely on Linux - * having the BSD setreuid() - */ - char tmpstr[PATH_MAX]; - uid_t ruid = getuid(); - gid_t egid = getegid(); - - /* avoid snprintf - old systems do not have it, or worse, - have a libc in which snprintf is the same as sprintf */ - if (strlen(pwd->pw_dir) + sizeof(_PATH_HUSHLOGIN) + 2 > - PATH_MAX) - cxt.quiet = 0; - else { - sprintf(tmpstr, "%s/%s", pwd->pw_dir, _PATH_HUSHLOGIN); - setregid(-1, pwd->pw_gid); - setreuid(0, pwd->pw_uid); - cxt.quiet = (effective_access(tmpstr, O_RDONLY) == 0); - setuid(0); /* setreuid doesn't do it alone! */ - setreuid(ruid, 0); - setregid(-1, egid); - } - } + cxt.quiet = get_hushlogin_status(pwd); log_utmp(&cxt); log_audit(&cxt, 1); |