Jonathan Nieder <jrnieder@xxxxxxxxx> writes: > Proposed fix: because of case (1), I would like a way to tell Git to > stop trusting any files in .git. That is: > > 1. Introduce a (configurable) list of "safe" configuration items that > can be set in .git/config and don't respect any others. The list of "safe" things are configurable by having something in ~/.gitconfig, perhaps? How would this work, from the end-user's point of view, with "git config --global" and "git config --local"? > 2. But what if I want to set a different pager per-repository? > I think we could do this using configuration "profiles". > My ~/.config/git/profiles/ directory would contain git-style > config files for repositories to include. Repositories could > then contain > > [include] > path = ~/.config/git/profiles/fancy-log-pager > > to make use of those settings. The facility (1) would > special-case this directory to allow it to set "unsafe" settings > since files there are assumed not to be under the control of an > attacker. Meaning, "include" is not in "safe" category, but a value that begins with "~/.config/git/" are excempt??? > 3. Likewise for hooks: my ~/.config/git/hooks/ directory would > contain hooks for repositories to make use of. Repositories could > symlink to hook files from there to make use of them. I am not sure what this means. .git/hooks/pre-commit being a symbolic link to "~/.config/git/hooks/pre-commit-fancy" (i.e. readlink gives the path with tilde unexpanded), so that the attacked sysadmin will not run it from ~attacker/.config/git/hooks? And the code that finds a hook to run sees .git/hooks/pre-commit, resolves the symlink manually and makes sure it leads to somewhere inside ~/.config/... (otherwise it rejects) and then uses the pointed-at copy? At that point, we are not taking any advantage of symbolic-link-ness of the entity, so .git/hooks/pre-commit being a text file that has a single like, e.g. # safe-hook: pre-commit-fancy may be sufficient (and we do not have to worry about systems without symbolic links)? The machinery that used to manually resolved symlink instead reads it, finds "pre-commit-fancy" in ~/.config/git/hooks/ and runs it, and you get the same behaviour, no? > One downside of (3) is its reliance on symlinks. Some alternatives: > > 3b. Use core.hooksPath configuration instead. Rely on (2). > 3c. Introduce new hook.* configuration to be used instead of hook > scripts. Rely on (2). I guess I invented 3d. without reading ahead X-<. None of the 3x variants other than 3 proper will not work for scripts and existing code that sees that .git/hooks/pre-commit is an executable and runs it, and 3 proper will not work without symbolic links, so this means we'd need "git locate-hook pre-commit" (and underlying locate_hook() helper API) that returns "/home/me/.git/config/hook/pre-commit-fancy" or fails when we do this transition. In an unconverted repository, it may return $PWD/.git/hooks/pre-commit, or failure if we are running under the paranoid mode. Sounds workable.
