From 34f7ea15c10fb72db73257c697156797832337c6 Mon Sep 17 00:00:00 2001 From: Karel Zak Date: Fri, 18 Nov 2011 12:26:19 +0100 Subject: login: improve pam_setcred() usage Reported-by: Thorsten Kukuk Signed-off-by: Karel Zak --- login-utils/login.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) (limited to 'login-utils/login.c') diff --git a/login-utils/login.c b/login-utils/login.c index 93ed2d62a..0d6c390de 100644 --- a/login-utils/login.c +++ b/login-utils/login.c @@ -863,16 +863,37 @@ static void loginpam_acct(struct login_context *cxt) } } +/* + * Note that position of the pam_setcred() call is discussable: + * + * - the PAM docs recommends pam_setcred() before pam_open_session() + * - but the original RFC http://www.opengroup.org/rfc/mirror-rfc/rfc86.0.txt + * uses pam_setcred() after pam_open_session() + * + * The old login versions (before year 2011) followed the RFC. This is probably + * not optimal, because there could be dependence between some session modules + * and user's credentials. + * + * The best is probably to follow openssh and call pam_setcred() before and + * after pam_open_session(). -- kzak@redhat.com (18-Nov-2011) + * + */ static void loginpam_session(struct login_context *cxt) { int rc; pam_handle_t *pamh = cxt->pamh; - rc = pam_open_session(pamh, 0); + rc = pam_setcred(pamh, PAM_ESTABLISH_CRED); if (is_pam_failure(rc)) loginpam_err(pamh, rc); - rc = pam_setcred(pamh, PAM_ESTABLISH_CRED); + rc = pam_open_session(pamh, 0); + if (is_pam_failure(rc)) { + pam_setcred(cxt->pamh, PAM_DELETE_CRED); + loginpam_err(pamh, rc); + } + + rc = pam_setcred(pamh, PAM_REINITIALIZE_CRED); if (is_pam_failure(rc)) { pam_close_session(pamh, 0); loginpam_err(pamh, rc); -- cgit v1.2.3-55-g7522