linux-stable.git/net/bpf, branch v5.11

bpf: Reject too big ctx_size_in for raw_tp test run

2021-01-14T03:31:43+00:00

syzbot reported a WARNING for allocating too big memory:

WARNING: CPU: 1 PID: 8484 at mm/page_alloc.c:4976 __alloc_pages_nodemask+0x5f8/0x730 mm/page_alloc.c:5011
Modules linked in:
CPU: 1 PID: 8484 Comm: syz-executor862 Not tainted 5.11.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__alloc_pages_nodemask+0x5f8/0x730 mm/page_alloc.c:4976
Code: 00 00 0c 00 0f 85 a7 00 00 00 8b 3c 24 4c 89 f2 44 89 e6 c6 44 24 70 00 48 89 6c 24 58 e8 d0 d7 ff ff 49 89 c5 e9 ea fc ff ff <0f> 0b e9 b5 fd ff ff 89 74 24 14 4c 89 4c 24 08 4c 89 74 24 18 e8
RSP: 0018:ffffc900012efb10 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 1ffff9200025df66 RCX: 0000000000000000
RDX: 0000000000000000 RSI: dffffc0000000000 RDI: 0000000000140dc0
RBP: 0000000000140dc0 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff81b1f7e1 R11: 0000000000000000 R12: 0000000000000014
R13: 0000000000000014 R14: 0000000000000000 R15: 0000000000000000
FS:  000000000190c880(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f08b7f316c0 CR3: 0000000012073000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
alloc_pages_current+0x18c/0x2a0 mm/mempolicy.c:2267
alloc_pages include/linux/gfp.h:547 [inline]
kmalloc_order+0x2e/0xb0 mm/slab_common.c:837
kmalloc_order_trace+0x14/0x120 mm/slab_common.c:853
kmalloc include/linux/slab.h:557 [inline]
kzalloc include/linux/slab.h:682 [inline]
bpf_prog_test_run_raw_tp+0x4b5/0x670 net/bpf/test_run.c:282
bpf_prog_test_run kernel/bpf/syscall.c:3120 [inline]
__do_sys_bpf+0x1ea9/0x4f10 kernel/bpf/syscall.c:4398
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x440499
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffe1f3bfb18 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440499
RDX: 0000000000000048 RSI: 0000000020000600 RDI: 000000000000000a
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401ca0
R13: 0000000000401d30 R14: 0000000000000000 R15: 0000000000000000

This is because we didn't filter out too big ctx_size_in. Fix it by
rejecting ctx_size_in that are bigger than MAX_BPF_FUNC_ARGS (12) u64
numbers.

Fixes: 1b4d60ec162f ("bpf: Enable BPF_PROG_TEST_RUN for raw_tracepoint")
Reported-by: syzbot+4f98876664c7337a4ae6@syzkaller.appspotmail.com
Signed-off-by: Song Liu 
Signed-off-by: Alexei Starovoitov 
Acked-by: Yonghong Song 
Link: https://lore.kernel.org/bpf/20210112234254.1906829-1-songliubraving@fb.com

bpf: fix raw_tp test run in preempt kernel

2020-09-30T15:34:08+00:00

In preempt kernel, BPF_PROG_TEST_RUN on raw_tp triggers:

[   35.874974] BUG: using smp_processor_id() in preemptible [00000000]
code: new_name/87
[   35.893983] caller is bpf_prog_test_run_raw_tp+0xd4/0x1b0
[   35.900124] CPU: 1 PID: 87 Comm: new_name Not tainted 5.9.0-rc6-g615bd02bf #1
[   35.907358] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS 1.10.2-1ubuntu1 04/01/2014
[   35.916941] Call Trace:
[   35.919660]  dump_stack+0x77/0x9b
[   35.923273]  check_preemption_disabled+0xb4/0xc0
[   35.928376]  bpf_prog_test_run_raw_tp+0xd4/0x1b0
[   35.933872]  ? selinux_bpf+0xd/0x70
[   35.937532]  __do_sys_bpf+0x6bb/0x21e0
[   35.941570]  ? find_held_lock+0x2d/0x90
[   35.945687]  ? vfs_write+0x150/0x220
[   35.949586]  do_syscall_64+0x2d/0x40
[   35.953443]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fix this by calling migrate_disable() before smp_processor_id().

Fixes: 1b4d60ec162f ("bpf: Enable BPF_PROG_TEST_RUN for raw_tracepoint")
Reported-by: Alexei Starovoitov 
Signed-off-by: Song Liu 
Signed-off-by: Alexei Starovoitov

bpf: Enable BPF_PROG_TEST_RUN for raw_tracepoint

2020-09-28T19:52:36+00:00

Add .test_run for raw_tracepoint. Also, introduce a new feature that runs
the target program on a specific CPU. This is achieved by a new flag in
bpf_attr.test, BPF_F_TEST_RUN_ON_CPU. When this flag is set, the program
is triggered on cpu with id bpf_attr.test.cpu. This feature is needed for
BPF programs that handle perf_event and other percpu resources, as the
program can access these resource locally.

Signed-off-by: Song Liu 
Signed-off-by: Daniel Borkmann 
Acked-by: John Fastabend 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20200925205432.1777-2-songliubraving@fb.com

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva

bpf: Allow to specify ifindex for skb in bpf_prog_test_run_skb

2020-08-03T21:32:23+00:00

Now skb->dev is unconditionally set to the loopback device in current net
namespace. But if we want to test bpf program which contains code branch
based on ifindex condition (eg filters out localhost packets) it is useful
to allow specifying of ifindex from userspace. This patch adds such option
through ctx_in (__sk_buff) parameter.

Signed-off-by: Dmitry Yakunin 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20200803090545.82046-3-zeil@yandex-team.ru

bpf: Setup socket family and addresses in bpf_prog_test_run_skb

2020-08-03T21:31:59+00:00

Now it's impossible to test all branches of cgroup_skb bpf program which
accesses skb->family and skb->{local,remote}_ip{4,6} fields because they
are zeroed during socket allocation. This commit fills socket family and
addresses from related fields in constructed skb.

Signed-off-by: Dmitry Yakunin 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20200803090545.82046-2-zeil@yandex-team.ru

bpf: Add tests for PTR_TO_BTF_ID vs. null comparison

2020-06-30T20:21:29+00:00

Add two tests for PTR_TO_BTF_ID vs. null ptr comparison,
one for PTR_TO_BTF_ID in the ctx structure and the
other for PTR_TO_BTF_ID after one level pointer chasing.
In both cases, the test ensures condition is not
removed.

For example, for this test
 struct bpf_fentry_test_t {
     struct bpf_fentry_test_t *a;
 };
 int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
 {
     if (arg == 0)
         test7_result = 1;
     return 0;
 }
Before the previous verifier change, we have xlated codes:
  int test7(long long unsigned int * ctx):
  ; int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
     0: (79) r1 = *(u64 *)(r1 +0)
  ; int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
     1: (b4) w0 = 0
     2: (95) exit
After the previous verifier change, we have:
  int test7(long long unsigned int * ctx):
  ; int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
     0: (79) r1 = *(u64 *)(r1 +0)
  ; if (arg == 0)
     1: (55) if r1 != 0x0 goto pc+4
  ; test7_result = 1;
     2: (18) r1 = map[id:6][0]+48
     4: (b7) r2 = 1
     5: (7b) *(u64 *)(r1 +0) = r2
  ; int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
     6: (b4) w0 = 0
     7: (95) exit

Signed-off-by: Yonghong Song 
Signed-off-by: Daniel Borkmann 
Acked-by: John Fastabend 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20200630171241.2523875-1-yhs@fb.com

bpf: Fix too large copy from user in bpf_test_init

2020-05-19T15:56:34+00:00

Commit bc56c919fce7 ("bpf: Add xdp.frame_sz in bpf_prog_test_run_xdp().")
recently changed bpf_prog_test_run_xdp() to use larger frames for XDP in
order to test tail growing frames (via bpf_xdp_adjust_tail) and to have
memory backing frame better resemble drivers.

The commit contains a bug, as it tries to copy the max data size from
userspace, instead of the size provided by userspace.  This cause XDP
unit tests to fail sporadically with EFAULT, an unfortunate behavior.
The fix is to only copy the size specified by userspace.

Fixes: bc56c919fce7 ("bpf: Add xdp.frame_sz in bpf_prog_test_run_xdp().")
Signed-off-by: Jesper Dangaard Brouer 
Signed-off-by: Daniel Borkmann 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/158980712729.256597.6115007718472928659.stgit@firesoul

bpf: Add xdp.frame_sz in bpf_prog_test_run_xdp().

2020-05-15T04:21:56+00:00

Update the memory requirements, when adding xdp.frame_sz in BPF test_run
function bpf_prog_test_run_xdp() which e.g. is used by XDP selftests.

Specifically add the expected reserved tailroom, but also allocated a
larger memory area to reflect that XDP frames usually comes in this
format. Limit the provided packet data size to 4096 minus headroom +
tailroom, as this also reflect a common 3520 bytes MTU limit with XDP.

Note that bpf_test_init already use a memory allocation method that clears
memory.  Thus, this already guards against leaking uninit kernel memory.

Signed-off-by: Jesper Dangaard Brouer 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/158945349549.97035.15316291762482444006.stgit@firesoul

bpf: Fix build warning regarding missing prototypes

2020-03-28T17:13:18+00:00

Fix build warnings when building net/bpf/test_run.o with W=1 due
to missing prototype for bpf_fentry_test{1..6}.

Instead of declaring prototypes, turn off warnings with
__diag_{push,ignore,pop} as pointed out by Alexei.

Signed-off-by: Jean-Philippe Menil 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20200327204713.28050-1-jpmenil@gmail.com