Patch "bpf: fix wrong exposure of map_flags into fdinfo for lpm" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

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 4.9-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-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Fri Mar  9 14:20:51 PST 2018
From: Daniel Borkmann <daniel@iogearbox.net>
Date: Thu,  8 Mar 2018 16:17:32 +0100
Subject: bpf: fix wrong exposure of map_flags into fdinfo for lpm
To: gregkh@linuxfoundation.org
Cc: ast@kernel.org, daniel@iogearbox.net, stable@vger.kernel.org, "David S . Miller" <davem@davemloft.net>
Message-ID: <d0c41d2614afbe10501cc3d96d998952694bab7f.1520521792.git.daniel@iogearbox.net>

From: Daniel Borkmann <daniel@iogearbox.net>

[ 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.

Fixes: b95a5c4db09b ("bpf: add a longest prefix match trie map implementation")
Reported-by: Jarno Rajahalme <jarno@covalent.io>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/bpf/arraymap.c |    1 +
 kernel/bpf/stackmap.c |    1 +
 2 files changed, 2 insertions(+)

--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -107,6 +107,7 @@ 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)
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -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 daniel@iogearbox.net are

queue-4.9/bpf-fix-mlock-precharge-on-arraymaps.patch
queue-4.9/bpf-x64-implement-retpoline-for-tail-call.patch
queue-4.9/bpf-arm64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.9/bpf-fix-wrong-exposure-of-map_flags-into-fdinfo-for-lpm.patch
queue-4.9/bpf-ppc64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.9/bpf-add-schedule-points-in-percpu-arrays-management.patch