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authorMichael Haggerty <mhagger@alum.mit.edu>2017-05-22 16:17:35 +0200
committerJunio C Hamano <gitster@pobox.com>2017-05-23 14:29:52 +0900
commitb9c8e7f2fb6ee19defeaa2927a0af42b525d8b33 (patch)
tree95c057da36e50b4b34fe9a48f538020c6fb85b7d /refs
parent04aea8d4df199836da3802f08cb5738eae66fa6c (diff)
downloadgit-b9c8e7f2fb6ee19defeaa2927a0af42b525d8b33.tar.gz
prefix_ref_iterator: don't trim too much
The `trim` parameter can be set independently of `prefix`. So if some caller were to set `trim` to be greater than `strlen(prefix)`, we could end up pointing the `refname` field of the iterator past the NUL of the actual reference name string. That can't happen currently, because `trim` is always set either to zero or to `strlen(prefix)`. But even the latter could lead to confusion, if a refname is exactly equal to the prefix, because then we would set the outgoing `refname` to the empty string. And we're about to decouple the `prefix` and `trim` arguments even more, so let's be cautious here. Report a bug if ever asked to trim a reference whose name is not longer than `trim`. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'refs')
-rw-r--r--refs/iterator.c18
1 files changed, 17 insertions, 1 deletions
diff --git a/refs/iterator.c b/refs/iterator.c
index bce1f192f7..4cf449ef66 100644
--- a/refs/iterator.c
+++ b/refs/iterator.c
@@ -292,7 +292,23 @@ static int prefix_ref_iterator_advance(struct ref_iterator *ref_iterator)
if (!starts_with(iter->iter0->refname, iter->prefix))
continue;
- iter->base.refname = iter->iter0->refname + iter->trim;
+ if (iter->trim) {
+ /*
+ * It is nonsense to trim off characters that
+ * you haven't already checked for via a
+ * prefix check, whether via this
+ * `prefix_ref_iterator` or upstream in
+ * `iter0`). So if there wouldn't be at least
+ * one character left in the refname after
+ * trimming, report it as a bug:
+ */
+ if (strlen(iter->iter0->refname) <= iter->trim)
+ die("BUG: attempt to trim too many characters");
+ iter->base.refname = iter->iter0->refname + iter->trim;
+ } else {
+ iter->base.refname = iter->iter0->refname;
+ }
+
iter->base.oid = iter->iter0->oid;
iter->base.flags = iter->iter0->flags;
return ITER_OK;