From 82a96e3dc0ee8f45bb0c1fe17a0cec1db7582e8f Mon Sep 17 00:00:00 2001 From: jinyaoguo Date: Mon, 9 Jun 2025 20:31:17 +0200 Subject: [PATCH] patch 9.1.1443: potential buffer underflow in insertchar() Problem: potential buffer underflow in insertchar() Solution: verify that end_len is larger than zero (jinyaoguo) When parsing the end-comment leader, end_len can be zero if copy_option_part() writes no characters. The existing check unconditionally accessed lead_end[end_len-1], causing potential underflow when end_len == 0. This change adds an end_len > 0 guard to ensure we only index lead_end if there is at least one character. closes: #17476 Signed-off-by: jinyaoguo Signed-off-by: Christian Brabandt --- src/edit.c | 2 +- src/version.c | 2 ++ 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/src/edit.c b/src/edit.c index b4e6767f2c..9cc55ef3d7 100644 --- a/src/edit.c +++ b/src/edit.c @@ -2197,7 +2197,7 @@ insertchar( i -= middle_len; // Check some expected things before we go on - if (i >= 0 && lead_end[end_len - 1] == end_comment_pending) + if (i >= 0 && end_len > 0 && lead_end[end_len - 1] == end_comment_pending) { // Backspace over all the stuff we want to replace backspace_until_column(i); diff --git a/src/version.c b/src/version.c index 6e0081e9bb..491b51690e 100644 --- a/src/version.c +++ b/src/version.c @@ -709,6 +709,8 @@ static char *(features[]) = static int included_patches[] = { /* Add new patch number below this line */ +/**/ + 1443, /**/ 1442, /**/