2004893 - CVE-2021-3778 vim: heap-based buffer overflow in utf_ptr2char() in mbyte.c [rhel-9.0]

Resolves: rhbz#2004893

0001-patch-8.2.3409-reading-beyond-end-of-line-with-inval.patch

@@ -0,0 +1,48 @@
+From 65b605665997fad54ef39a93199e305af2fe4d7f Mon Sep 17 00:00:00 2001
+From: Bram Moolenaar <Bram@vim.org>
+Date: Tue, 7 Sep 2021 19:26:53 +0200
+Subject: [PATCH] patch 8.2.3409: reading beyond end of line with invalid utf-8
+ character
+
+Problem:    Reading beyond end of line with invalid utf-8 character.
+Solution:   Check for NUL when advancing.
+---
+ src/regexp_nfa.c                 | 3 ++-
+ src/testdir/test_regexp_utf8.vim | 8 ++++++++
+ src/version.c                    | 2 ++
+ 3 files changed, 12 insertions(+), 1 deletion(-)
+
+diff --git a/src/regexp_nfa.c b/src/regexp_nfa.c
+index 9757d7c47..c7db98187 100644
+--- a/src/regexp_nfa.c
++++ b/src/regexp_nfa.c
+@@ -5664,7 +5664,8 @@ find_match_text(colnr_T startcol, int regstart, char_u *match_text)
+ 		match = FALSE;
+ 		break;
+ 	    }
+-	    len2 += MB_CHAR2LEN(c2);
++	    len2 += enc_utf8 ? utf_ptr2len(rex.line + col + len2)
++							     : MB_CHAR2LEN(c2);
+ 	}
+ 	if (match
+ 		// check that no composing char follows
+diff --git a/src/testdir/test_regexp_utf8.vim b/src/testdir/test_regexp_utf8.vim
+index 9f0ffb9aa..044aeffb6 100644
+--- a/src/testdir/test_regexp_utf8.vim
++++ b/src/testdir/test_regexp_utf8.vim
+@@ -558,4 +558,12 @@ func Test_match_char_class_upper()
+   bwipe!
+ endfunc
+ 
++func Test_match_invalid_byte()
++  call writefile(0z630a.765d30aa0a.2e0a.790a.4030, 'Xinvalid')
++  new
++  source Xinvalid
++  bwipe!
++  call delete('Xinvalid')
++endfunc
++
+ " vim: shiftwidth=2 sts=2 expandtab
+-- 
+2.31.1
+

vim.spec

@@ -72,6 +72,8 @@ Patch3019: 0001-patch-8.2.3115-Coverity-complains-about-free_wininfo.patch
 Patch3020: 0001-patch-8.2.3290-Vim9-compiling-dict-may-use-pointer-a.patch
 # 2002320 - CVE-2021-3770 vim: using retab with large value may lead to heap buffer overflow [rhel-9.0]
 Patch3021: vim-cve-var-retab.patch
+# 2004893 - CVE-2021-3778 vim: heap-based buffer overflow in utf_ptr2char() in mbyte.c [rhel-9.0]
+Patch3022: 0001-patch-8.2.3409-reading-beyond-end-of-line-with-inval.patch
 
 # gcc is no longer in buildroot by default
 BuildRequires: gcc
@@ -280,6 +282,7 @@ perl -pi -e "s,bin/nawk,bin/awk,g" runtime/tools/mve.awk
 %patch3019 -p1 -b .covscan-free-wininfo
 %patch3020 -p1 -b .covscan-key-freed
 %patch3021 -p1 -b .cve-var-retab
+%patch3022 -p1 -b .cve-utf-ptrchar
 
 %build
 cd src
@@ -843,6 +846,7 @@ touch %{buildroot}/%{_datadir}/%{name}/vimfiles/doc/tags
 - 2011429 - Remove downstream patch vim-7.4-nowarning.patch
 - 2011749 - Update test suite to work without default mouse behavior
 - 2002320 - CVE-2021-3770 vim: using retab with large value may lead to heap buffer overflow [rhel-9.0]
+- 2004893 - CVE-2021-3778 vim: heap-based buffer overflow in utf_ptr2char() in mbyte.c [rhel-9.0]
 
 * Tue Aug 10 2021 Mohan Boddu <mboddu@redhat.com> - 2:8.2.2637-5
 - Rebuilt for IMA sigs, glibc 2.34, aarch64 flags