From: Karel Zak <kzak@redhat.com>
Date: Wed, 3 Feb 2021 13:45:15 +0000 (+0100)
Subject: su: use full tty path for PAM_TTY
X-Git-Tag: v2.37-rc1~142
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=61653767371048c805ae8032951476c547d19e09;p=thirdparty%2Futil-linux.git

su: use full tty path for PAM_TTY

pam_set_item() man page:
 PAM_TTY
   The terminal name: prefixed by /dev/ if it is a device file;
   for graphical, X-based, applications the value for this item
   should be the $DISPLAY variable.

It seems for example pam_timestamp module is not robust enough to
differentiate between /dev/ and pty/0 and it assumes that '/' in the
path always means '/dev/' prefix ...

Fixes: https://github.com/karelzak/util-linux/issues/1242
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/login-utils/su-common.c b/login-utils/su-common.c
index a544c1b875..caf20adc56 100644
--- a/login-utils/su-common.c
+++ b/login-utils/su-common.c
@@ -128,6 +128,7 @@ struct su_context {
 	struct passwd	*pwd;			/* new user info */
 	char		*pwdbuf;		/* pwd strings */
 
+	const char	*tty_path;		/* tty device path */
 	const char	*tty_name;		/* tty_path without /dev prefix */
 	const char	*tty_number;		/* end of the tty_path */
 
@@ -178,7 +179,7 @@ static void init_tty(struct su_context *su)
 	su->isterm = isatty(STDIN_FILENO) ? 1 : 0;
 	DBG(TTY, ul_debug("initialize [is-term=%s]", su->isterm ? "true" : "false"));
 	if (su->isterm)
-		get_terminal_name(NULL, &su->tty_name, &su->tty_number);
+		get_terminal_name(&su->tty_path, &su->tty_name, &su->tty_number);
 }
 
 /*
@@ -366,8 +367,8 @@ static void supam_authenticate(struct su_context *su)
 	if (is_pam_failure(rc))
 		goto done;
 
-	if (su->tty_name) {
-		rc = pam_set_item(su->pamh, PAM_TTY, su->tty_name);
+	if (su->tty_path) {
+		rc = pam_set_item(su->pamh, PAM_TTY, su->tty_path);
 		if (is_pam_failure(rc))
 			goto done;
 	}