From 388b96df319c62e9c8d984921b8967db37481d8a Mon Sep 17 00:00:00 2001 From: Jeff King Date: Wed, 28 Feb 2024 17:37:44 -0500 Subject: [PATCH] upload-pack: use oidset for deepen_not list We record the oid of every deepen-not line the client sends to us. For a well-behaved client, the resulting array should be bounded by the number of unique refs we have. But because there's no de-duplication, a malicious client can cause the array to grow unbounded by just sending the same "refs/heads/foo" over and over (assuming such a ref exists). Since the deepen-not list is just being fed to a "rev-list --not" traversal, the order of items doesn't matter. So we can replace the oid_array with an oidset which notices and skips duplicates. That bounds the memory in malicious cases to be linear in the number of unique refs. And even in non-malicious cases, there may be a slight improvement in memory usage if multiple refs point to the same oid (though in practice this list is probably pretty tiny anyway, as it comes from the user specifying "--shallow-exclude" on the client fetch). Note that in the trace2 output we'll now output the number of de-duplicated objects, rather than the total number of "deepen-not" lines we received. This is arguably a more useful value for tracing / debugging anyway. Reported-by: Benjamin Flesch Signed-off-by: Jeff King Signed-off-by: Junio C Hamano --- upload-pack.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/upload-pack.c b/upload-pack.c index f6395b210e..ebad9026d7 100644 --- a/upload-pack.c +++ b/upload-pack.c @@ -65,7 +65,7 @@ struct upload_pack_data { struct strvec hidden_refs; struct object_array shallows; - struct oid_array deepen_not; + struct oidset deepen_not; struct object_array extra_edge_obj; int depth; timestamp_t deepen_since; @@ -125,7 +125,7 @@ static void upload_pack_data_init(struct upload_pack_data *data) struct object_array want_obj = OBJECT_ARRAY_INIT; struct object_array have_obj = OBJECT_ARRAY_INIT; struct object_array shallows = OBJECT_ARRAY_INIT; - struct oid_array deepen_not = OID_ARRAY_INIT; + struct oidset deepen_not = OID_ARRAY_INIT; struct string_list uri_protocols = STRING_LIST_INIT_DUP; struct object_array extra_edge_obj = OBJECT_ARRAY_INIT; struct string_list allowed_filters = STRING_LIST_INIT_DUP; @@ -158,7 +158,7 @@ static void upload_pack_data_clear(struct upload_pack_data *data) object_array_clear(&data->want_obj); object_array_clear(&data->have_obj); object_array_clear(&data->shallows); - oid_array_clear(&data->deepen_not); + oidset_clear(&data->deepen_not); object_array_clear(&data->extra_edge_obj); list_objects_filter_release(&data->filter_options); string_list_clear(&data->allowed_filters, 0); @@ -923,12 +923,13 @@ static int send_shallow_list(struct upload_pack_data *data) strvec_push(&av, "rev-list"); if (data->deepen_since) strvec_pushf(&av, "--max-age=%"PRItime, data->deepen_since); - if (data->deepen_not.nr) { + if (oidset_size(&data->deepen_not)) { + const struct object_id *oid; + struct oidset_iter iter; strvec_push(&av, "--not"); - for (i = 0; i < data->deepen_not.nr; i++) { - struct object_id *oid = data->deepen_not.oid + i; + oidset_iter_init(&data->deepen_not, &iter); + while ((oid = oidset_iter_next(&iter))) strvec_push(&av, oid_to_hex(oid)); - } strvec_push(&av, "--not"); } for (i = 0; i < data->want_obj.nr; i++) { @@ -1004,7 +1005,7 @@ static int process_deepen_since(const char *line, timestamp_t *deepen_since, int return 0; } -static int process_deepen_not(const char *line, struct oid_array *deepen_not, int *deepen_rev_list) +static int process_deepen_not(const char *line, struct oidset *deepen_not, int *deepen_rev_list) { const char *arg; if (skip_prefix(line, "deepen-not ", &arg)) { @@ -1012,7 +1013,7 @@ static int process_deepen_not(const char *line, struct oid_array *deepen_not, in struct object_id oid; if (expand_ref(the_repository, arg, strlen(arg), &oid, &ref) != 1) die("git upload-pack: ambiguous deepen-not: %s", line); - oid_array_append(deepen_not, &oid); + oidset_insert(deepen_not, &oid); free(ref); *deepen_rev_list = 1; return 1; @@ -1554,7 +1555,7 @@ static void trace2_fetch_info(struct upload_pack_data *data) jw_object_intmax(&jw, "depth", data->depth); jw_object_intmax(&jw, "shallows", data->shallows.nr); jw_object_bool(&jw, "deepen-since", data->deepen_since); - jw_object_intmax(&jw, "deepen-not", data->deepen_not.nr); + jw_object_intmax(&jw, "deepen-not", oidset_size(&data->deepen_not)); jw_object_bool(&jw, "deepen-relative", data->deepen_relative); if (data->filter_options.choice) jw_object_string(&jw, "filter", list_object_filter_config_name(data->filter_options.choice)); -- 2.11.4.GIT