Patch "bpf: fix wrong exposure of map_flags into fdinfo for lpm" has been added to the 4.11-stable tree

This is a note to let you know that I've just added the patch titled

bpf: fix wrong exposure of map_flags into fdinfo for lpm

to the 4.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
bpf-fix-wrong-exposure-of-map_flags-into-fdinfo-for-lpm.patch
and it can be found in the queue-4.11 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Daniel Borkmann <[email protected]>
Date: Thu, 25 May 2017 01:05:08 +0200
Subject: bpf: fix wrong exposure of map_flags into fdinfo for lpm

From: Daniel Borkmann <[email protected]>

[ Upstream commit a316338cb71a3260201490e615f2f6d5c0d8fb2c ]

trie_alloc() always needs to have BPF_F_NO_PREALLOC passed in via attr->map_flags, since it does not support preallocation yet. We check the flag, but we never copy the flag into trie->map.map_flags, which is later on exposed into fdinfo and used by loaders such as iproute2. Latter uses this in bpf_map_selfcheck_pinned() to test whether a pinned map has the same spec as the one from the BPF obj file and if not, bails out, which is currently the case for lpm since it exposes always 0 as flags.

Also copy over flags in array_map_alloc() and stack_map_alloc(). They always have to be 0 right now, but we should make sure to not miss to copy them over at a later point in time when we add actual flags for them to use.

---
 kernel/bpf/arraymap.c |    1 +
 kernel/bpf/lpm_trie.c |    1 +
 kernel/bpf/stackmap.c |    1 +
 3 files changed, 3 insertions(+)

@@ -83,6 +83,7 @@ static struct bpf_map *array_map_alloc(u
 	array->map.key_size = attr->key_size;
 	array->map.value_size = attr->value_size;
 	array->map.max_entries = attr->max_entries;
+	array->map.map_flags = attr->map_flags;
 	array->elem_size = elem_size;
 
 	if (!percpu)

@@ -432,6 +432,7 @@ static struct bpf_map *trie_alloc(union
 	trie->map.key_size = attr->key_size;
 	trie->map.value_size = attr->value_size;
 	trie->map.max_entries = attr->max_entries;
+	trie->map.map_flags = attr->map_flags;
 	trie->data_size = attr->key_size -
 			  offsetof(struct bpf_lpm_trie_key, data);
 	trie->max_prefixlen = trie->data_size * 8;

@@ -88,6 +88,7 @@ static struct bpf_map *stack_map_alloc(u
 	smap->map.key_size = attr->key_size;
 	smap->map.value_size = value_size;
 	smap->map.max_entries = attr->max_entries;
+	smap->map.map_flags = attr->map_flags;
 	smap->n_buckets = n_buckets;
 	smap->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.11/bpf-adjust-verifier-heuristics.patch queue-4.11/bpf-fix-wrong-exposure-of-map_flags-into-fdinfo-for-lpm.patch queue-4.11/bpf-arm64-fix-faulty-emission-of-map-access-in-tail-calls.patch queue-4.11/bpf-add-bpf_clone_redirect-to-bpf_helper_changes_pkt_data.patch