setup: sanity check file size in read_gitfile_gently

read_gitfile_gently will allocate a buffer to fit the entire file that
should be read. Add a sanity check of the file size before opening to
avoid allocating a potentially huge amount of memory if we come across
a large file that someone happened to name ".git". The limit is set to
a sufficiently unreasonable size that should never be exceeded by a
genuine .git file.

Signed-off-by: Erik Elfström <erik.elfstrom@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/cache.h b/cache.h
index 25578cb..858d9b3 100644
--- a/cache.h
+++ b/cache.h
@@ -454,6 +454,7 @@ extern const char *get_git_work_tree(void);
 #define READ_GITFILE_ERR_INVALID_FORMAT 5
 #define READ_GITFILE_ERR_NO_PATH 6
 #define READ_GITFILE_ERR_NOT_A_REPO 7
+#define READ_GITFILE_ERR_TOO_LARGE 8
 extern const char *read_gitfile_gently(const char *path, int *return_error_code);
 #define read_gitfile(path) read_gitfile_gently((path), NULL)
 extern const char *resolve_gitdir(const char *suspect);