Prior to Git 2.35.0, git could be run from an inaccessible working
directory so long as the git repository specified by options and/or
environment variables was accessible. For example:
git init repo
mkdir -p a/b
cd a/b
chmod u-x ..
git -C "${PWD%/a/b}/repo" status
If this example seems a bit contrived, consider running with the
repository owner as a substitute UID (e.g. with runuser(1) or sudo(8))
without ensuring the working directory is accessible by that user.
The code added by e6f8861bd4 ("setup: introduce
startup_info->original_cwd") to preserve the working directory attempts
to normalize the path using strbuf_realpath(). If that fails, as in the
case above, it is treated as a fatal error.
This commit treats strbuf_realpath() errors as non-fatal. If an error
occurs, setup_original_cwd() will continue without applying removal
prevention for cwd, resulting in the pre-2.35.0 behavior. The risk
should be minimal, since git will not operate on a repository with
inaccessible ancestors, this behavior is only known to occur when cwd is
a descendant of the repository, an ancestor of cwd is inaccessible, and
no ancestors of the repository are inaccessible.
Signed-off-by: Kevin Locke <kevin@xxxxxxxxxxxxxxx>
---
Changes since v3:
* Free tmp_original_cwd in both codepaths.
* Return after strbuf_realpath() fails, rather than jumping to
no_prevention_needed, to avoid unnecessary free(NULL) and NULL
reassignment.
* Invert the condition and remove the else block to match the
return-on-error code style for better readability.
* Stop adding "Try" to comment, since strbuf_realpath() hasn't
been optional since v1.
Changes since v2:
* Use trace2_data_string(), rather than trace_printf(), to report
realpath failure.
Changes since v1:
* Set startup_info->original_cwd = NULL when strbuf_realpath() fails,
rather than setting it to the un-normalized path.
* Add a trace message when realpath fails to aid debugging.
* Remove potential realpath failure cause from comment before it.
* Improve format for reference to e6f8861bd4 in commit message.
* Clarify when the pre-2.35.0 behavior may occur as a result of this
commit in the commit message.
* Remove 'Fixes:' tag from commit message.
setup.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/setup.c b/setup.c
index a7b36f3ffbf..e0a99df512f 100644
--- a/setup.c
+++ b/setup.c
@@ -459,7 +459,16 @@ static void setup_original_cwd(void)
*/
/* Normalize the directory */
- strbuf_realpath(&tmp, tmp_original_cwd, 1);
+ if (!strbuf_realpath(&tmp, tmp_original_cwd, 0)) {
+ trace2_data_string("setup", the_repository,
+ "realpath-path", tmp_original_cwd);
+ trace2_data_string("setup", the_repository,
+ "realpath-failure", strerror(errno));
+ free((char*)tmp_original_cwd);
+ tmp_original_cwd = NULL;
+ return;
+ }
+
free((char*)tmp_original_cwd);
tmp_original_cwd = NULL;
startup_info->original_cwd = strbuf_detach(&tmp, NULL);
--
2.35.1
