On Wed, Oct 17, 2018 at 10:39:49PM -0700, Song Liu wrote: > Tests are added to make sure CGROUP_SKB cannot access: > tc_classid, data_meta, flow_keys > > and can read and write: > mark, prority, and cb[0-4] > > and can read other fields. > > To make selftest with skb->sk work, a dummy sk is added in > bpf_prog_test_run_skb(). > > Signed-off-by: Song Liu <songliubrav...@fb.com> > --- > net/bpf/test_run.c | 4 + > tools/testing/selftests/bpf/test_verifier.c | 170 ++++++++++++++++++++ > 2 files changed, 174 insertions(+) > > diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c > index 0c423b8cd75c..c7210e2f1ae9 100644 > --- a/net/bpf/test_run.c > +++ b/net/bpf/test_run.c > @@ -10,6 +10,7 @@ > #include <linux/etherdevice.h> > #include <linux/filter.h> > #include <linux/sched/signal.h> > +#include <net/sock.h> > > static __always_inline u32 bpf_test_run_one(struct bpf_prog *prog, void *ctx, > struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE]) > @@ -115,6 +116,7 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const > union bpf_attr *kattr, > u32 retval, duration; > int hh_len = ETH_HLEN; > struct sk_buff *skb; > + struct sock sk; > void *data; > int ret; > > @@ -142,6 +144,8 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const > union bpf_attr *kattr, > kfree(data); > return -ENOMEM; > } > + sock_init_data(NULL, &sk); > + skb->sk = &sk;
I was about to apply it, but it crashes as: [ 16.830822] BUG: unable to handle kernel paging request at 000000014427b974 [ 16.831363] PGD 8000000135ecf067 P4D 8000000135ecf067 PUD 0 [ 16.831792] Oops: 0000 [#1] SMP PTI [ 16.832061] CPU: 1 PID: 1965 Comm: test_verifier Not tainted 4.19.0-rc7-02550-ga76dee97ff12 #1153 [ 16.832712] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014 [ 16.833358] RIP: 0010:cmp_map_id+0x10/0x50 [ 16.835036] RSP: 0018:ffffc9000080faf8 EFLAGS: 00010246 [ 16.835429] RAX: 00000000ffffffff RBX: 0000000036069ee8 RCX: 0000000000000000 [ 16.835958] RDX: 000000014427b970 RSI: 000000014427b970 RDI: ffffc9000080fb44 [ 16.836496] RBP: 000000000000000c R08: ffffffff810f7330 R09: 0000000036069ee8 [ 16.837026] R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000 [ 16.837554] R13: ffffffff810f7330 R14: 000000014427b970 R15: 000000001b034f74 [ 16.838083] FS: 00007fae50663700(0000) GS:ffff88013ba80000(0000) knlGS:0000000000000000 [ 16.838677] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 16.839105] CR2: 000000014427b974 CR3: 0000000135934005 CR4: 00000000003606e0 [ 16.839632] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 16.840157] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 16.840682] Call Trace: [ 16.840897] bsearch+0x50/0x90 [ 16.841144] map_id_range_down+0x81/0xa0 [ 16.841438] make_kuid+0xf/0x10 [ 16.841677] sock_init_data+0x24f/0x260 [ 16.841979] bpf_prog_test_run_skb+0x9e/0x270 I suspect sock_net_set(sk, &init_net) is necessary before sock_init_data() call.
