clone: fix directory traversal This was introduced in the initial version of this code, way back when in 2008. $ curl http://127.0.0.1/cgit/repo/objects/?path=../../../../../../../../../etc/passwd root:x:0:0:root:/root:/bin/sh ... Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Reported-by: Jann Horn <jannh@google.com>
Jason A. Donenfeld Jason@zx2c4.com
Fri, 03 Aug 2018 15:46:11 +0200
1 files changed,
19 insertions(+),
4 deletions(-)
jump to
M
ui-clone.c
→
ui-clone.c
@@ -92,17 +92,32 @@ }
void cgit_clone_objects(void) { - if (!ctx.qry.path) { - cgit_print_error_page(400, "Bad request", "Bad request"); - return; - } + char *p; + + if (!ctx.qry.path) + goto err; if (!strcmp(ctx.qry.path, "info/packs")) { print_pack_info(); return; } + /* Avoid directory traversal by forbidding "..", but also work around + * other funny business by just specifying a fairly strict format. For + * example, now we don't have to stress out about the Cygwin port. + */ + for (p = ctx.qry.path; *p; ++p) { + if (*p == '.' && *(p + 1) == '.') + goto err; + if (!isalnum(*p) && *p != '/' && *p != '.' && *p != '-') + goto err; + } + send_file(git_path("objects/%s", ctx.qry.path)); + return; + +err: + cgit_print_error_page(400, "Bad request", "Bad request"); } void cgit_clone_head(void)