From 6d02e1429771c00046b48f26e53ca4123c3ce4e1 Mon Sep 17 00:00:00 2001 From: Bram Moolenaar Date: Fri, 24 Sep 2021 16:01:09 +0800 Subject: [PATCH] patch 8.2.3428: using freed memory when replacing Problem: Using freed memory when replacing. (Dhiraj Mishra) Solution: Get the line pointer after calling ins_copychar(). Upstream-Status: Backport [https://github.com/vim/vim/commit/35a9a00afcb20897d462a766793ff45534810dc3] CVE: CVE-2021-3796 Signed-off-by: Mingli Yu --- src/normal.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/src/normal.c b/src/normal.c index c4963e621..305b514bc 100644 --- a/src/normal.c +++ b/src/normal.c @@ -5009,19 +5009,23 @@ nv_replace(cmdarg_T *cap) { /* * Get ptr again, because u_save and/or showmatch() will have - * released the line. At the same time we let know that the - * line will be changed. + * released the line. This may also happen in ins_copychar(). + * At the same time we let know that the line will be changed. */ - ptr = ml_get_buf(curbuf, curwin->w_cursor.lnum, TRUE); if (cap->nchar == Ctrl_E || cap->nchar == Ctrl_Y) { int c = ins_copychar(curwin->w_cursor.lnum + (cap->nchar == Ctrl_Y ? -1 : 1)); + + ptr = ml_get_buf(curbuf, curwin->w_cursor.lnum, TRUE); if (c != NUL) ptr[curwin->w_cursor.col] = c; } else + { + ptr = ml_get_buf(curbuf, curwin->w_cursor.lnum, TRUE); ptr[curwin->w_cursor.col] = cap->nchar; + } if (p_sm && msg_silent == 0) showmatch(cap->nchar); ++curwin->w_cursor.col; -- 2.17.1