Re: Bug#1098694: Crash in agetty due to invalid strncmp call in Trixie

* Chris Hofstaedtler <[email protected]> [250223 20:06]:
> > [..] After I sent this bug report yesterday, I also found out that
> > someone has reported what I believe is the same bug to
> > upstream a while ago ( https://github.com/util-linux/util-linux/issues/3304
> > ) but so far nobody has commented on that report.
> 
> Yeah, this seems like the same issue.

Below is a patch that works, but certainly feels dirty:


From: Chris Hofstaedtler <[email protected]>
Date: Sun, 23 Feb 2025 20:10:05 +0100
Subject: agetty: restore op->tty if getting the tty name fails

Signed-off-by: Chris Hofstaedtler <[email protected]>
---
 term-utils/agetty.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/term-utils/agetty.c b/term-utils/agetty.c
index a382313..e65c985 100644
--- a/term-utils/agetty.c
+++ b/term-utils/agetty.c
@@ -929,9 +929,11 @@ static void parse_args(int argc, char **argv, struct options *op)
 	/* resolve the tty path in case it was provided as stdin */
 	if (strcmp(op->tty, "-") == 0) {
 		op->tty_is_stdin = 1;
+		const char* tty_orig = op->tty;
 		int fd = get_terminal_name(NULL, &op->tty, NULL);
 		if (fd < 0) {
 			log_warn(_("could not get terminal name: %d"), fd);
+			op->tty = tty_orig;
 		}
 	}