Go to file
Justin M. Keyes 214bcf24cc fix(undo): crash on corrupted undo file #41339
Problem:
`:rundo` on a corrupted undo file crashes or hangs, instead of failing
with E825. Patching one 4-byte field is enough:

    ue_size = 0xFFFFFFFF  " walks a NULL ue_array
    ue_size = 0x7FFFFFF0  " 17 GB xmalloc + memset, then preserve_exit()
    ue_top  = 0xFFFFFFFB  " negative lnum reaches ml_delete()

Analysis:
Every count in the file is read with `undo_read_4c()` and then checked,
differently at each site. None bounds the value by what the file can
hold, so a 2 GB count reaches `xmalloc()`.

Note:
- Vim doesn't have `bi_fsize` because it checks `U_ALLOC_LINE` result
  everywhere (thus doesn't crash, but may thrash...); those checks were
  dropped when Nvim moved to `xmalloc()`, and the `ue_size` loop counter
  became unsigned.
- Vim *does* have the negative line numbers bug: `u_undoredo()` checks
  `top > ml_line_count || top >= bot || bot > ml_line_count + 1`, which
  rejects none of them.

Solution:
- Introduce `undo_read_len()` and use it to fail early instead of
  continuing with nonsense.
- Validate `ue_top`/`ue_bot`/ `ue_lcount`.
- Use `xcalloc()`, so no site can proceed with a NULL array.
- Report a truncated "U" line, distinguish EOF from a 0xFFFFFFFF field,
  and free the header on the extmark error path.
2026-08-16 10:24:24 -04:00
2025-12-30 01:44:52 -05:00
2026-03-13 12:29:44 +00:00
2025-01-11 10:34:12 +01:00
2026-04-18 15:38:59 -04:00
2026-03-11 18:00:18 +01:00
2026-04-16 10:48:11 -04:00

Neovim

Documentation | Chat

Coverity Scan analysis Packages Debian CI Downloads

Neovim is a project that seeks to aggressively refactor Vim in order to:

See the Introduction wiki page and Roadmap for more information.

Features

See :help nvim-features for the full list, and :help news for noteworthy changes in the latest version!

Install from package

Pre-built packages for Windows, macOS, and Linux are found on the Releases page.

Managed packages are in Homebrew, Debian, Ubuntu, Fedora, Arch Linux, Void Linux, Gentoo, and more!

Install from source

See BUILD.md and supported platforms for details.

The build is CMake-based, but a Makefile is provided as a convenience. After installing the dependencies, run the following command.

make CMAKE_BUILD_TYPE=RelWithDebInfo
sudo make install

To install to a non-default location:

make CMAKE_BUILD_TYPE=RelWithDebInfo CMAKE_INSTALL_PREFIX=/full/path/
make install

CMake hints for inspecting the build:

  • cmake --build build --target help lists all build targets.
  • build/CMakeCache.txt (or cmake -LAH build/) contains the resolved values of all CMake variables.
  • build/compile_commands.json shows the full compiler invocations for each translation unit.

Transitioning from Vim

See :help nvim-from-vim for instructions.

Project layout

├─ cmake/           CMake utils
├─ cmake.config/    CMake defines
├─ cmake.deps/      subproject to fetch and build dependencies (optional)
├─ runtime/         plugins and docs
├─ src/nvim/        application source code (see src/nvim/README.md)
│  ├─ api/          API subsystem
│  ├─ eval/         Vimscript subsystem
│  ├─ event/        event-loop subsystem
│  ├─ generators/   code generation (pre-compilation)
│  ├─ lib/          generic data structures
│  ├─ lua/          Lua subsystem
│  ├─ msgpack_rpc/  RPC subsystem
│  ├─ os/           low-level platform code
│  └─ tui/          built-in UI
└─ test/            tests (see test/README.md)

License

Neovim contributions since b17d96 are licensed under the Apache 2.0 license, except for contributions copied from Vim (identified by the vim-patch token). See LICENSE.txt for details.

Description
Vim-fork focused on extensibility and usability
Readme 509 MiB
Languages
Vim Script 39.7%
Lua 32.6%
C 26.7%
CMake 0.4%
Zig 0.2%
Other 0.1%