diff options
authorJeff King <>2017-04-29 12:36:44 (GMT)
committerJunio C Hamano <>2017-05-05 03:07:27 (GMT)
commit3ec804490a265f4c418a321428c12f3f18b7eff5 (patch)
parent765428699a5381f113d19974720bc91b5bfeaf1d (diff)
shell: disallow repo names beginning with dash
When a remote server uses git-shell, the client side will connect to it like: ssh server "git-upload-pack 'foo.git'" and we literally exec ("git-upload-pack", "foo.git"). In early versions of upload-pack and receive-pack, we took a repository argument and nothing else. But over time they learned to accept dashed options. If the user passes a repository name that starts with a dash, the results are confusing at best (we complain of a bogus option instead of a non-existent repository) and malicious at worst (the user can start an interactive pager via "--help"). We could pass "--" to the sub-process to make sure the user's argument is interpreted as a branch name. I.e.: git-upload-pack -- -foo.git But adding "--" automatically would make us inconsistent with a normal shell (i.e., when git-shell is not in use), where "-foo.git" would still be an error. For that case, the client would have to specify the "--", but they can't do so reliably, as existing versions of git-shell do not allow more than a single argument. The simplest thing is to simply disallow "-" at the start of the repo name argument. This hasn't worked either with or without git-shell since version 1.0.0, and nobody has complained. Note that this patch just applies to do_generic_cmd(), which runs upload-pack, receive-pack, and upload-archive. There are two other types of commands that git-shell runs: - do_cvs_cmd(), but this already restricts the argument to be the literal string "server" - admin-provided commands in the git-shell-commands directory. We'll pass along arbitrary arguments there, so these commands could have similar problems. But these commands might actually understand dashed arguments, so we cannot just block them here. It's up to the writer of the commands to make sure they are safe. With great power comes great responsibility. Reported-by: Timo Schmid <> Signed-off-by: Jeff King <> Signed-off-by: Junio C Hamano <>
1 files changed, 1 insertions, 1 deletions
diff --git a/shell.c b/shell.c
index ace62e4..c3bf8ec 100644
--- a/shell.c
+++ b/shell.c
@@ -13,7 +13,7 @@ static int do_generic_cmd(const char *me, char *arg)
const char *my_argv[4];
- if (!arg || !(arg = sq_dequote(arg)))
+ if (!arg || !(arg = sq_dequote(arg)) || *arg == '-')
die("bad argument");
if (!starts_with(me, "git-"))
die("bad command");