| From foo@baz Wed Apr 11 10:26:56 CEST 2018 |
| From: Davide Caratti <dcaratti@redhat.com> |
| Date: Fri, 6 Apr 2018 01:19:37 +0200 |
| Subject: net/sched: fix NULL dereference in the error path of tcf_bpf_init() |
| |
| From: Davide Caratti <dcaratti@redhat.com> |
| |
| |
| [ Upstream commit 3239534a79ee6f20cffd974173a1e62e0730e8ac ] |
| |
| when tcf_bpf_init_from_ops() fails (e.g. because of program having invalid |
| number of instructions), tcf_bpf_cfg_cleanup() calls bpf_prog_put(NULL) or |
| bpf_prog_destroy(NULL). Unless CONFIG_BPF_SYSCALL is unset, this causes |
| the following error: |
| |
| BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 |
| PGD 800000007345a067 P4D 800000007345a067 PUD 340e1067 PMD 0 |
| Oops: 0000 [#1] SMP PTI |
| Modules linked in: act_bpf(E) ip6table_filter ip6_tables iptable_filter binfmt_misc ext4 mbcache jbd2 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel snd_hda_codec_generic pcbc snd_hda_intel snd_hda_codec snd_hda_core snd_hwdep snd_seq snd_seq_device snd_pcm aesni_intel crypto_simd glue_helper cryptd joydev snd_timer snd virtio_balloon pcspkr soundcore i2c_piix4 nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c ata_generic pata_acpi qxl drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm virtio_blk drm virtio_net virtio_console i2c_core crc32c_intel serio_raw virtio_pci ata_piix libata virtio_ring floppy virtio dm_mirror dm_region_hash dm_log dm_mod [last unloaded: act_bpf] |
| CPU: 3 PID: 5654 Comm: tc Tainted: G E 4.16.0.bpf_test+ #408 |
| Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 |
| RIP: 0010:__bpf_prog_put+0xc/0xc0 |
| RSP: 0018:ffff9594003ef728 EFLAGS: 00010202 |
| RAX: 0000000000000000 RBX: ffff9594003ef758 RCX: 0000000000000024 |
| RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 |
| RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000044 |
| R10: 0000000000000220 R11: ffff8a7ab9f17131 R12: 0000000000000000 |
| R13: ffff8a7ab7c3c8e0 R14: 0000000000000001 R15: ffff8a7ab88f1054 |
| FS: 00007fcb2f17c740(0000) GS:ffff8a7abfd80000(0000) knlGS:0000000000000000 |
| CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 |
| CR2: 0000000000000020 CR3: 000000007c888006 CR4: 00000000001606e0 |
| Call Trace: |
| tcf_bpf_cfg_cleanup+0x2f/0x40 [act_bpf] |
| tcf_bpf_cleanup+0x4c/0x70 [act_bpf] |
| __tcf_idr_release+0x79/0x140 |
| tcf_bpf_init+0x125/0x330 [act_bpf] |
| tcf_action_init_1+0x2cc/0x430 |
| ? get_page_from_freelist+0x3f0/0x11b0 |
| tcf_action_init+0xd3/0x1b0 |
| tc_ctl_action+0x18b/0x240 |
| rtnetlink_rcv_msg+0x29c/0x310 |
| ? _cond_resched+0x15/0x30 |
| ? __kmalloc_node_track_caller+0x1b9/0x270 |
| ? rtnl_calcit.isra.29+0x100/0x100 |
| netlink_rcv_skb+0xd2/0x110 |
| netlink_unicast+0x17c/0x230 |
| netlink_sendmsg+0x2cd/0x3c0 |
| sock_sendmsg+0x30/0x40 |
| ___sys_sendmsg+0x27a/0x290 |
| ? mem_cgroup_commit_charge+0x80/0x130 |
| ? page_add_new_anon_rmap+0x73/0xc0 |
| ? do_anonymous_page+0x2a2/0x560 |
| ? __handle_mm_fault+0xc75/0xe20 |
| __sys_sendmsg+0x58/0xa0 |
| do_syscall_64+0x6e/0x1a0 |
| entry_SYSCALL_64_after_hwframe+0x3d/0xa2 |
| RIP: 0033:0x7fcb2e58eba0 |
| RSP: 002b:00007ffc93c496c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e |
| RAX: ffffffffffffffda RBX: 00007ffc93c497f0 RCX: 00007fcb2e58eba0 |
| RDX: 0000000000000000 RSI: 00007ffc93c49740 RDI: 0000000000000003 |
| RBP: 000000005ac6a646 R08: 0000000000000002 R09: 0000000000000000 |
| R10: 00007ffc93c49120 R11: 0000000000000246 R12: 0000000000000000 |
| R13: 00007ffc93c49804 R14: 0000000000000001 R15: 000000000066afa0 |
| Code: 5f 00 48 8b 43 20 48 c7 c7 70 2f 7c b8 c7 40 10 00 00 00 00 5b e9 a5 8b 61 00 0f 1f 44 00 00 0f 1f 44 00 00 41 54 55 48 89 fd 53 <48> 8b 47 20 f0 ff 08 74 05 5b 5d 41 5c c3 41 89 f4 0f 1f 44 00 |
| RIP: __bpf_prog_put+0xc/0xc0 RSP: ffff9594003ef728 |
| CR2: 0000000000000020 |
| |
| Fix it in tcf_bpf_cfg_cleanup(), ensuring that bpf_prog_{put,destroy}(f) |
| is called only when f is not NULL. |
| |
| Fixes: bbc09e7842a5 ("net/sched: fix idr leak on the error path of tcf_bpf_init()") |
| Reported-by: Lucas Bates <lucasb@mojatatu.com> |
| Signed-off-by: Davide Caratti <dcaratti@redhat.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/sched/act_bpf.c | 12 ++++++++---- |
| 1 file changed, 8 insertions(+), 4 deletions(-) |
| |
| --- a/net/sched/act_bpf.c |
| +++ b/net/sched/act_bpf.c |
| @@ -245,10 +245,14 @@ static int tcf_bpf_init_from_efd(struct |
| |
| static void tcf_bpf_cfg_cleanup(const struct tcf_bpf_cfg *cfg) |
| { |
| - if (cfg->is_ebpf) |
| - bpf_prog_put(cfg->filter); |
| - else |
| - bpf_prog_destroy(cfg->filter); |
| + struct bpf_prog *filter = cfg->filter; |
| + |
| + if (filter) { |
| + if (cfg->is_ebpf) |
| + bpf_prog_put(filter); |
| + else |
| + bpf_prog_destroy(filter); |
| + } |
| |
| kfree(cfg->bpf_ops); |
| kfree(cfg->bpf_name); |