patch 9.0.2121: [security]: use-after-free in ex_substitute Commit: https://github.com/vim/vim/commit/26c11c56888d01e298cd8044caf860f3c26f57bb Author: Christian Brabandt <cb@256bit.org> Date: Wed Nov 22 21:26:41 2023 +0100 patch 9.0.2121: [security]: use-after-free in ex_substitute Problem: [security]: use-after-free in ex_substitute Solution: always allocate memory closes: #13552 A recursive :substitute command could cause a heap-use-after free in Vim (CVE-2023-48706). The whole reproducible test is a bit tricky, I can only reproduce this reliably when no previous substitution command has been used yet (which is the reason, the test needs to run as first one in the test_substitute.vim file) and as a combination of the `:~` command together with a :s command that contains the special substitution atom `~\=` which will make use of a sub-replace special atom and calls a vim script function. There was a comment in the existing :s code, that already makes the `sub` variable allocate memory so that a recursive :s call won't be able to cause any issues here, so this was known as a potential problem already. But for the current test-case that one does not work, because the substitution does not start with `\=` but with `~\=` (and since there does not yet exist a previous substitution atom, Vim will simply increment the `sub` pointer (which then was not allocated dynamically) and later one happily use a sub-replace special expression (which could then free the `sub` var). The following commit fixes this, by making the sub var always using allocated memory, which also means we need to free the pointer whenever we leave the function. Since sub is now always an allocated variable, we also do no longer need the sub_copy variable anymore, since this one was used to indicated when sub pointed to allocated memory (and had therefore to be freed on exit) and when not. Github Security Advisory: https://github.com/vim/vim/security/advisories/GHSA-c8qm-x72m-q53q Signed-off-by: Christian Brabandt <cb@256bit.org>

README_vms.txt for version 9.0 of Vim: Vi IMproved.

This file explains the installation of Vim on VMS systems.
See "README.txt" in the runtime archive for information about Vim.


Most information can be found in the on-line documentation.  Use ":help vms"
inside Vim.  Or get the runtime files and read runtime/doc/os_vms.txt to find
out how to install and configure Vim with runtime files etc.

To compile Vim yourself you need three archives:
  vim-X.X-rt.tar.gz	runtime files
  vim-X.X-src.tar.gz	source files
  vim-X.X-extra.tar.gz	extra source files

Compilation is recommended, in order to make sure that the correct
libraries are used for your specific system.  Read about compiling in
src/INSTALLvms.txt.

To use the binary version, you need one of these archives:

  vim-XX-exe-ia64-gui.zip       IA64 GUI/Motif executables
  vim-XX-exe-ia64-gtk.zip       IA64 GUI/GTK executables
  vim-XX-exe-ia64-term.zip      IA64 console executables
  vim-XX-exe-axp-gui.zip	Alpha GUI/Motif executables
  vim-XX-exe-axp-gtk.zip	Alpha GUI/GTK executables
  vim-XX-exe-axp-term.zip       Alpha console executables
  vim-XX-exe-vax-gui.zip	VAX GUI executables
  vim-XX-exe-vax-term.zip       VAX console executables

and of course
  vim-XX-runtime.zip		runtime files

The binary archives contain: vim.exe, ctags.exe, xxd.exe files,
but there are also prepared "deploy ready" archives:

vim-XX-ia64.zip			GUI and console executables with runtime and
				help files for IA64 systems
vim-XX-axp.zip			GUI and console executables with runtime and
				help files for Alpha systems
vim-XX-vax.zip			GUI and console executables with runtime and
				help files for VAX systems

GTK builds need LIBGTK library installed.

These executables and up to date patches for OpenVMS system are downloadable
from http://www.polarhome.com/vim/ or ftp://ftp.polarhome.com/pub/vim/