safe.directory: normalize the checked path

The pathname of a repository comes from getcwd() and it could be a
path aliased via symbolic links, e.g., the real directory may be
/home/u/repository but a symbolic link /home/u/repo may point at it,
and the clone request may come as "git clone file:///home/u/repo/".

A request to check if /home/u/repo is safe would be rejected if the
safe.directory configuration allows /home/u/repository/ but not its
alias /home/u/repo/.  Normalize the path being checked before
comparing with safe.directory value(s).

Suggested-by: Phillip Wood <phillip.wood123@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 12 insertions, 4 deletions

diff --git a/setup.c b/setup.c
index 3177d010d1..54cce7219b 100644
--- a/setup.c
+++ b/setup.c
@@ -1215,7 +1215,7 @@ static int canonicalize_ceiling_entry(struct string_list_item *item,
 }
 
 struct safe_directory_data {
-	const char *path;
+	char *path;
 	int is_safe;
 };
 
@@ -1261,9 +1261,7 @@ static int ensure_valid_ownership(const char *gitfile,
 				  const char *worktree, const char *gitdir,
 				  struct strbuf *report)
 {
-	struct safe_directory_data data = {
-		.path = worktree ? worktree : gitdir
-	};
+	struct safe_directory_data data = { 0 };
 
 	if (!git_env_bool("GIT_TEST_ASSUME_DIFFERENT_OWNER", 0) &&
 	    (!gitfile || is_path_owned_by_current_user(gitfile, report)) &&
@@ -1272,12 +1270,22 @@ static int ensure_valid_ownership(const char *gitfile,
 		return 1;
 
 	/*
+	 * normalize the data.path for comparison with normalized paths
+	 * that come from the configuration file.  The path is unsafe
+	 * if it cannot be normalized.
+	 */
+	data.path = real_pathdup(worktree ? worktree : gitdir, 0);
+	if (!data.path)
+		return 0;
+
+	/*
 	 * data.path is the "path" that identifies the repository and it is
 	 * constant regardless of what failed above. data.is_safe should be
 	 * initialized to false, and might be changed by the callback.
 	 */
 	git_protected_config(safe_directory_cb, &data);
 
+	free(data.path);
 	return data.is_safe;
 }