linux-stable.git/kernel/bpf/local_storage.c, branch v4.19.78

bpf: allocate local storage buffers using GFP_ATOMIC

2018-12-17T08:24:33+00:00

[ Upstream commit 569a933b03f3c48b392fe67c0086b3a6b9306b5a ]

Naresh reported an issue with the non-atomic memory allocation of
cgroup local storage buffers:

[   73.047526] BUG: sleeping function called from invalid context at
/srv/oe/build/tmp-rpb-glibc/work-shared/intel-corei7-64/kernel-source/mm/slab.h:421
[   73.060915] in_atomic(): 1, irqs_disabled(): 0, pid: 3157, name: test_cgroup_sto
[   73.068342] INFO: lockdep is turned off.
[   73.072293] CPU: 2 PID: 3157 Comm: test_cgroup_sto Not tainted
4.20.0-rc2-next-20181113 #1
[   73.080548] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS
2.0b 07/27/2017
[   73.088018] Call Trace:
[   73.090463]  dump_stack+0x70/0xa5
[   73.093783]  ___might_sleep+0x152/0x240
[   73.097619]  __might_sleep+0x4a/0x80
[   73.101191]  __kmalloc_node+0x1cf/0x2f0
[   73.105031]  ? cgroup_storage_update_elem+0x46/0x90
[   73.109909]  cgroup_storage_update_elem+0x46/0x90

cgroup_storage_update_elem() (as well as other update map update
callbacks) is called with disabled preemption, so GFP_ATOMIC
allocation should be used: e.g. alloc_htab_elem() in hashtab.c.

Reported-by: Naresh Kamboju 
Tested-by: Naresh Kamboju 
Signed-off-by: Roman Gushchin 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin

bpf: don't accept cgroup local storage with zero value size

2018-10-02T12:42:23+00:00

Explicitly forbid creating cgroup local storage maps with zero value
size, as it makes no sense and might even cause a panic.

Reported-by: syzbot+18628320d3b14a5c459c@syzkaller.appspotmail.com
Signed-off-by: Roman Gushchin 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Signed-off-by: Daniel Borkmann

bpf: harden flags check in cgroup_storage_update_elem()

2018-09-28T13:50:23+00:00

cgroup_storage_update_elem() shouldn't accept any flags
argument values except BPF_ANY and BPF_EXIST to guarantee
the backward compatibility, had a new flag value been added.

Fixes: de9cbbaadba5 ("bpf: introduce cgroup storage maps")
Signed-off-by: Roman Gushchin 
Reported-by: Daniel Borkmann 
Cc: Alexei Starovoitov 
Signed-off-by: Daniel Borkmann

bpf: decouple btf from seq bpf fs dump and enable more maps

2018-08-12T22:52:45+00:00

Commit a26ca7c982cb ("bpf: btf: Add pretty print support to
the basic arraymap") and 699c86d6ec21 ("bpf: btf: add pretty
print for hash/lru_hash maps") enabled support for BTF and
dumping via BPF fs for array and hash/lru map. However, both
can be decoupled from each other such that regular BPF maps
can be supported for attaching BTF key/value information,
while not all maps necessarily need to dump via map_seq_show_elem()
callback.

The basic sanity check which is a prerequisite for all maps
is that key/value size has to match in any case, and some maps
can have extra checks via map_check_btf() callback, e.g.
probing certain types or indicating no support in general. With
that we can also enable retrieving BTF info for per-cpu map
types and lpm.

Signed-off-by: Daniel Borkmann 
Acked-by: Alexei Starovoitov 
Acked-by: Yonghong Song

bpf: pass a pointer to a cgroup storage using pcpu variable

2018-08-02T22:47:32+00:00

This commit introduces the bpf_cgroup_storage_set() helper,
which will be used to pass a pointer to a cgroup storage
to the bpf helper.

Signed-off-by: Roman Gushchin 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Acked-by: Martin KaFai Lau 
Signed-off-by: Daniel Borkmann

bpf: introduce cgroup storage maps

2018-08-02T22:47:32+00:00

This commit introduces BPF_MAP_TYPE_CGROUP_STORAGE maps:
a special type of maps which are implementing the cgroup storage.

>From the userspace point of view it's almost a generic
hash map with the (cgroup inode id, attachment type) pair
used as a key.

The only difference is that some operations are restricted:
  1) a user can't create new entries,
  2) a user can't remove existing entries.

The lookup from userspace is o(log(n)).

Signed-off-by: Roman Gushchin 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Acked-by: Martin KaFai Lau 
Signed-off-by: Daniel Borkmann