path: root/builtin
diff options
authorJeff King <>2017-03-28 19:45:43 (GMT)
committerJunio C Hamano <>2017-03-28 22:28:04 (GMT)
commit594fa9998c41277c579a94657100fa303160aa7e (patch)
treec3cf4c5d51f96a603b4244e14316ca59c9300075 /builtin
parent892e723afd2b5696e4d75280e730bf9f1ea92329 (diff)
odb_mkstemp: write filename into strbuf
The odb_mkstemp() function expects the caller to provide a fixed buffer to write the resulting tempfile name into. But it creates the template using snprintf without checking the return value. This means we could silently truncate the filename. In practice, it's unlikely that the truncation would end in the template-pattern that mkstemp needs to open the file. So we'd probably end up failing either way, unless the path was specially crafted. The simplest fix would be to notice the truncation and die. However, we can observe that most callers immediately xstrdup() the result anyway. So instead, let's switch to using a strbuf, which is easier for them (and isn't a big deal for the other 2 callers, who can just strbuf_release when they're done with it). Note that many of the callers used static buffers, but this was purely to avoid putting a large buffer on the stack. We never passed the static buffers out of the function, so there's no complicated memory handling we need to change. Signed-off-by: Jeff King <>
Diffstat (limited to 'builtin')
1 files changed, 3 insertions, 3 deletions
diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 49e7175..f4af2ab 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -307,10 +307,10 @@ static const char *open_pack_file(const char *pack_name)
if (from_stdin) {
input_fd = 0;
if (!pack_name) {
- static char tmp_file[PATH_MAX];
- output_fd = odb_mkstemp(tmp_file, sizeof(tmp_file),
+ struct strbuf tmp_file = STRBUF_INIT;
+ output_fd = odb_mkstemp(&tmp_file,
- pack_name = xstrdup(tmp_file);
+ pack_name = strbuf_detach(&tmp_file, NULL);
} else {
output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
if (output_fd < 0)