git: 8647fe60b8c3 - stable/13 - tty: properly check character position when handling IUTF8 backspaces
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Date: Mon, 20 Nov 2023 16:58:10 UTC
The branch stable/13 has been updated by christos: URL: https://cgit.FreeBSD.org/src/commit/?id=8647fe60b8c3cc03cf1d53d281f9306b7043543b commit 8647fe60b8c3cc03cf1d53d281f9306b7043543b Author: Bojan Novković <bojan.novkovic@fer.hr> AuthorDate: 2023-11-13 18:02:30 +0000 Commit: Christos Margiolis <christos@FreeBSD.org> CommitDate: 2023-11-20 16:57:49 +0000 tty: properly check character position when handling IUTF8 backspaces The tty_rubchar() code handling backspaces for UTF-8 characters didn't properly check whether the beginning of the current line was reached. This resulted in a kernel panic in ttyinq_unputchar() when prodded with certain malformed UTF-8 sequences. PR: 275009 Reviewed by: christos Differential Revision: https://reviews.freebsd.org/D42564 (cherry picked from commit c6d7be214811c315d234d64c6cbaa92d4f55d2c1) --- sys/kern/tty_ttydisc.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/sys/kern/tty_ttydisc.c b/sys/kern/tty_ttydisc.c index c46579cefbb1..cb5bf672d040 100644 --- a/sys/kern/tty_ttydisc.c +++ b/sys/kern/tty_ttydisc.c @@ -822,7 +822,13 @@ ttydisc_rubchar(struct tty *tp) /* Loop back through inq until we hit the * leading byte. */ while (CTL_UTF8_CONT(c) && nb < UTF8_STACKBUF) { - ttyinq_peekchar(&tp->t_inq, &c, "e); + /* + * Check if we've reached the beginning + * of the line. + */ + if (ttyinq_peekchar(&tp->t_inq, &c, + "e) != 0) + break; ttyinq_unputchar(&tp->t_inq); bytes[curidx] = c; curidx--;