Junio C HamanoIf somebody wants to dip his or her toe in git hacking, and is tempted to send in a "clean up" patch (e.g. whitespace, coding style) that does not really _fix_ anything, please don't.
I have a task of similar complexity (meaning, reasonably easy) that is much more useful and appreciated than clean-up patches for you.
The callback functions that are passed to git_config() need to be audited so that they do not barf when given NULL. Currently, many of them are not safe.
A callback function of git_config() is called when the command reads value from .git/config and friends. The function takes two parameters, var and value. var is never NULL and it is the name of the configuration variable found in the file being read. value could be either string or NULL.
A NULL value is boolean "true". For example, on MS-DOS, you may have something like this:
[core] autocrlf
and your callback will be called with var = "core.autocrlf" and value = NULL in such a case.
If you want to fix them (you do not have to do all of them, and if you would like to help, please make one patch per function fixed), the procedure is:
(1) Find calling sites for git_config(). For example, we find
one in archive-tar.c::write_tar_archive(). int write_tar_archive(struct archiver_args *args)
{
int plen = args->base ? strlen(args->base) : 0;git_config(git_tar_config);
archive_time = args->time;
verbose = args->verbose;
...(2) Look at the function that is passed to git_config().
static int git_tar_config(const char *var, const char *value)
{
if (!strcmp(var, "tar.umask")) {
if (!strcmp(value, "user")) {
tar_umask = umask(0);
umask(tar_umask);
} else {
tar_umask = git_config_int(var, value);
}
return 0;
}
return git_default_config(var, value);
}(3) Let's fix it. If the user's configuration has:
[tar]
umask it is an illegal configuration, but the code above does not
check for NULL, and the second strcmp() would fail. If we
guard that strcmp() with a check against NULL, we would be
Ok. git_config_int() will correctly barf telling the user
that "tar.umask" configuration is wrong. (4) Then send in a patch. Again, one patch per fixed function,
please. The message may look like this:-- >8 -- [PATCH] archive-tar.c: guard config parser from value=NULL
Signed-off-by: A U Thor <author@example.com>
archive-tar.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/archive-tar.c b/archive-tar.c index e1bced5..30aa2e2 100644 --- a/archive-tar.c +++ b/archive-tar.c @@ -222,7 +222,7 @@ static void write_global_extended_header(const unsigned char *sha1) static int git_tar_config(const char *var, const char *value) { if (!strcmp(var, "tar.umask")) { - if (!strcmp(value, "user")) { + if (value && !strcmp(value, "user")) { tar_umask = umask(0); umask(tar_umask); } else {
