From aab179d937379e28c67dcab0a46fdba05c11d919 Mon Sep 17 00:00:00 2001 From: Taylor Blau Date: Thu, 3 Dec 2020 13:55:13 -0500 Subject: [PATCH 1/2] builtin/clone.c: don't ignore transport_fetch_refs() errors If 'git clone' couldn't execute 'transport_fetch_refs()' (e.g., because of an error on the remote's side in 'git upload-pack'), then it will silently ignore it. Even though this has been the case at least since clone was ported to C (way back in 8434c2f1af (Build in clone, 2008-04-27)), 'git fetch' doesn't ignore these and reports any failures it sees. That suggests that ignoring the return value in 'git clone' is simply an oversight that should be corrected. That's exactly what this patch does. (Noticing and fixing this is no coincidence, we'll want it in the next patch in order to demonstrate a regression in 'git upload-pack' via a 'git clone'.) There's no additional logging here, but that matches how 'git fetch' handles the same case. An assumption there is that whichever part of transport_fetch_refs() fails will complain loudly, so any additional logging here is redundant. Co-authored-by: Jeff King Signed-off-by: Jeff King Signed-off-by: Taylor Blau Signed-off-by: Junio C Hamano --- builtin/clone.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/builtin/clone.c b/builtin/clone.c index a0841923cf..a5630337e4 100644 --- a/builtin/clone.c +++ b/builtin/clone.c @@ -1293,8 +1293,11 @@ int cmd_clone(int argc, const char **argv, const char *prefix) break; } - if (!is_local && !complete_refs_before_fetch) - transport_fetch_refs(transport, mapped_refs); + if (!is_local && !complete_refs_before_fetch) { + err = transport_fetch_refs(transport, mapped_refs); + if (err) + goto cleanup; + } remote_head = find_ref_by_name(refs, "HEAD"); remote_head_points_at = @@ -1339,8 +1342,11 @@ int cmd_clone(int argc, const char **argv, const char *prefix) if (is_local) clone_local(path, git_dir); - else if (refs && complete_refs_before_fetch) - transport_fetch_refs(transport, mapped_refs); + else if (refs && complete_refs_before_fetch) { + err = transport_fetch_refs(transport, mapped_refs); + if (err) + goto cleanup; + } update_remote_refs(refs, mapped_refs, remote_head_points_at, branch_top.buf, reflog_msg.buf, transport, @@ -1367,6 +1373,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix) junk_mode = JUNK_LEAVE_REPO; err = checkout(submodule_progress); +cleanup: free(remote_name); strbuf_release(&reflog_msg); strbuf_release(&branch_top); From 8d133f500a5390a089988141cdec8154a732764d Mon Sep 17 00:00:00 2001 From: Taylor Blau Date: Thu, 3 Dec 2020 13:55:18 -0500 Subject: [PATCH 2/2] upload-pack.c: don't free allowed_filters util pointers To keep track of which object filters are allowed or not, 'git upload-pack' stores the name of each filter in a string_list, and sets it ->util pointer to be either 0 or 1, indicating whether it is banned or allowed. Later on, we attempt to clear that list, but we incorrectly ask for the util pointers to be free()'d, too. This behavior (introduced back in 6dd3456a8c (upload-pack.c: allow banning certain object filter(s), 2020-08-03)) leads to an invalid free, and causes us to crash. In order to trigger this, one needs to fetch from a server that (a) has at least one object filter allowed, and (b) issue a fetch that contains a subset of the allowed filters (i.e., we cannot ask for a banned filter, since this causes us to die() before we hit the bogus string_list_clear()). In that case, whatever banned filters exist will cause a noop free() (since those ->util pointers are set to 0), but the first allowed filter we try to free will crash us. We never noticed this in the tests because we didn't have an example of setting 'uploadPackFilter' configuration variables and then following up with a valid fetch. The first new 'git clone' prevents further regression here. For good measure on top, add a test which checks the same behavior at a tree depth greater than 0. Signed-off-by: Taylor Blau Signed-off-by: Junio C Hamano --- t/t5616-partial-clone.sh | 10 +++++++++- upload-pack.c | 2 +- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/t/t5616-partial-clone.sh b/t/t5616-partial-clone.sh index f4d49d8335..5da945cf15 100755 --- a/t/t5616-partial-clone.sh +++ b/t/t5616-partial-clone.sh @@ -281,7 +281,15 @@ test_expect_success 'upload-pack limits tree depth filters' ' test_config -C srv.bare uploadpackfilter.tree.maxDepth 0 && test_must_fail ok=sigpipe git clone --no-checkout --filter=tree:1 \ "file://$(pwd)/srv.bare" pc3 2>err && - test_i18ngrep "tree filter allows max depth 0, but got 1" err + test_i18ngrep "tree filter allows max depth 0, but got 1" err && + + git clone --no-checkout --filter=tree:0 "file://$(pwd)/srv.bare" pc4 && + + test_config -C srv.bare uploadpackfilter.tree.maxDepth 5 && + git clone --no-checkout --filter=tree:5 "file://$(pwd)/srv.bare" pc5 && + test_must_fail ok=sigpipe git clone --no-checkout --filter=tree:6 \ + "file://$(pwd)/srv.bare" pc6 2>err && + test_i18ngrep "tree filter allows max depth 5, but got 6" err ' test_expect_success 'partial clone fetches blobs pointed to by refs even if normally filtered out' ' diff --git a/upload-pack.c b/upload-pack.c index 1006bebd50..be8fffbc07 100644 --- a/upload-pack.c +++ b/upload-pack.c @@ -154,7 +154,7 @@ static void upload_pack_data_clear(struct upload_pack_data *data) string_list_clear(&data->deepen_not, 0); object_array_clear(&data->extra_edge_obj); list_objects_filter_release(&data->filter_options); - string_list_clear(&data->allowed_filters, 1); + string_list_clear(&data->allowed_filters, 0); free((char *)data->pack_objects_hook); }