| Message ID | 20210525132152.2589420-1-vladbu@nvidia.com |
|---|---|
| State | New |
| Headers | show |
| Series | [net,v2] net: zero-initialize tc skb extension on allocation | expand |
On Tue, May 25, 2021 at 6:22 AM Vlad Buslov <vladbu@nvidia.com> wrote: > > Function skb_ext_add() doesn't initialize created skb extension with any > value and leaves it up to the user. However, since extension of type > TC_SKB_EXT originally contained only single value tc_skb_ext->chain its > users used to just assign the chain value without setting whole extension > memory to zero first. This assumption changed when TC_SKB_EXT extension was > extended with additional fields but not all users were updated to > initialize the new fields which leads to use of uninitialized memory > afterwards. UBSAN log: Hm, I thought the memset() in __skb_ext_alloc() does the job, clearly I was wrong. [...] > > Fix the issue by providing new function tc_skb_ext_alloc() that allocates > tc skb extension and initializes its memory to 0 before returning it to the > caller. Change all existing users to use new API instead of calling > skb_ext_add() directly. Just a note: struct tc_skb_ext is currently only 8-byte long, so memset() it should not be a problem for performance. > > Fixes: 038ebb1a713d ("net/sched: act_ct: fix miss set mru for ovs after defrag in act_ct") > Fixes: d29334c15d33 ("net/sched: act_api: fix miss set post_ct for ovs after do conntrack in act_ct") > Signed-off-by: Vlad Buslov <vladbu@nvidia.com> Acked-by: Cong Wang <cong.wang@bytedance.com> Thanks.
Hello: This patch was applied to netdev/net.git (refs/heads/master): On Tue, 25 May 2021 16:21:52 +0300 you wrote: > Function skb_ext_add() doesn't initialize created skb extension with any > value and leaves it up to the user. However, since extension of type > TC_SKB_EXT originally contained only single value tc_skb_ext->chain its > users used to just assign the chain value without setting whole extension > memory to zero first. This assumption changed when TC_SKB_EXT extension was > extended with additional fields but not all users were updated to > initialize the new fields which leads to use of uninitialized memory > afterwards. UBSAN log: > > [...] Here is the summary with links: - [net,v2] net: zero-initialize tc skb extension on allocation https://git.kernel.org/netdev/net/c/9453d45ecb6c You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/rep/tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en/rep/tc.c index 6cdc52d50a48..311382261840 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/rep/tc.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/rep/tc.c @@ -626,7 +626,7 @@ static bool mlx5e_restore_skb(struct sk_buff *skb, u32 chain, u32 reg_c1, struct mlx5_eswitch *esw; u32 zone_restore_id; - tc_skb_ext = skb_ext_add(skb, TC_SKB_EXT); + tc_skb_ext = tc_skb_ext_alloc(skb); if (!tc_skb_ext) { WARN_ON(1); return false; diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c index bccdb43a880b..2c776e7a7692 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c @@ -5090,7 +5090,7 @@ bool mlx5e_tc_update_skb(struct mlx5_cqe64 *cqe, if (mapped_obj.type == MLX5_MAPPED_OBJ_CHAIN) { chain = mapped_obj.chain; - tc_skb_ext = skb_ext_add(skb, TC_SKB_EXT); + tc_skb_ext = tc_skb_ext_alloc(skb); if (WARN_ON(!tc_skb_ext)) return false; diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h index 255e4f4b521f..ec7823921bd2 100644 --- a/include/net/pkt_cls.h +++ b/include/net/pkt_cls.h @@ -709,6 +709,17 @@ tc_cls_common_offload_init(struct flow_cls_common_offload *cls_common, cls_common->extack = extack; } +#if IS_ENABLED(CONFIG_NET_TC_SKB_EXT) +static inline struct tc_skb_ext *tc_skb_ext_alloc(struct sk_buff *skb) +{ + struct tc_skb_ext *tc_skb_ext = skb_ext_add(skb, TC_SKB_EXT); + + if (tc_skb_ext) + memset(tc_skb_ext, 0, sizeof(*tc_skb_ext)); + return tc_skb_ext; +} +#endif + enum tc_matchall_command { TC_CLSMATCHALL_REPLACE, TC_CLSMATCHALL_DESTROY, diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index 40fbea626dfd..279f9e2a2319 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -1624,7 +1624,7 @@ int tcf_classify_ingress(struct sk_buff *skb, /* If we missed on some chain */ if (ret == TC_ACT_UNSPEC && last_executed_chain) { - ext = skb_ext_add(skb, TC_SKB_EXT); + ext = tc_skb_ext_alloc(skb); if (WARN_ON_ONCE(!ext)) return TC_ACT_SHOT; ext->chain = last_executed_chain;
Function skb_ext_add() doesn't initialize created skb extension with any value and leaves it up to the user. However, since extension of type TC_SKB_EXT originally contained only single value tc_skb_ext->chain its users used to just assign the chain value without setting whole extension memory to zero first. This assumption changed when TC_SKB_EXT extension was extended with additional fields but not all users were updated to initialize the new fields which leads to use of uninitialized memory afterwards. UBSAN log: [ 778.299821] UBSAN: invalid-load in net/openvswitch/flow.c:899:28 [ 778.301495] load of value 107 is not a valid value for type '_Bool' [ 778.303215] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.12.0-rc7+ #2 [ 778.304933] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 778.307901] Call Trace: [ 778.308680] <IRQ> [ 778.309358] dump_stack+0xbb/0x107 [ 778.310307] ubsan_epilogue+0x5/0x40 [ 778.311167] __ubsan_handle_load_invalid_value.cold+0x43/0x48 [ 778.312454] ? memset+0x20/0x40 [ 778.313230] ovs_flow_key_extract.cold+0xf/0x14 [openvswitch] [ 778.314532] ovs_vport_receive+0x19e/0x2e0 [openvswitch] [ 778.315749] ? ovs_vport_find_upcall_portid+0x330/0x330 [openvswitch] [ 778.317188] ? create_prof_cpu_mask+0x20/0x20 [ 778.318220] ? arch_stack_walk+0x82/0xf0 [ 778.319153] ? secondary_startup_64_no_verify+0xb0/0xbb [ 778.320399] ? stack_trace_save+0x91/0xc0 [ 778.321362] ? stack_trace_consume_entry+0x160/0x160 [ 778.322517] ? lock_release+0x52e/0x760 [ 778.323444] netdev_frame_hook+0x323/0x610 [openvswitch] [ 778.324668] ? ovs_netdev_get_vport+0xe0/0xe0 [openvswitch] [ 778.325950] __netif_receive_skb_core+0x771/0x2db0 [ 778.327067] ? lock_downgrade+0x6e0/0x6f0 [ 778.328021] ? lock_acquire+0x565/0x720 [ 778.328940] ? generic_xdp_tx+0x4f0/0x4f0 [ 778.329902] ? inet_gro_receive+0x2a7/0x10a0 [ 778.330914] ? lock_downgrade+0x6f0/0x6f0 [ 778.331867] ? udp4_gro_receive+0x4c4/0x13e0 [ 778.332876] ? lock_release+0x52e/0x760 [ 778.333808] ? dev_gro_receive+0xcc8/0x2380 [ 778.334810] ? lock_downgrade+0x6f0/0x6f0 [ 778.335769] __netif_receive_skb_list_core+0x295/0x820 [ 778.336955] ? process_backlog+0x780/0x780 [ 778.337941] ? mlx5e_rep_tc_netdevice_event_unregister+0x20/0x20 [mlx5_core] [ 778.339613] ? seqcount_lockdep_reader_access.constprop.0+0xa7/0xc0 [ 778.341033] ? kvm_clock_get_cycles+0x14/0x20 [ 778.342072] netif_receive_skb_list_internal+0x5f5/0xcb0 [ 778.343288] ? __kasan_kmalloc+0x7a/0x90 [ 778.344234] ? mlx5e_handle_rx_cqe_mpwrq+0x9e0/0x9e0 [mlx5_core] [ 778.345676] ? mlx5e_xmit_xdp_frame_mpwqe+0x14d0/0x14d0 [mlx5_core] [ 778.347140] ? __netif_receive_skb_list_core+0x820/0x820 [ 778.348351] ? mlx5e_post_rx_mpwqes+0xa6/0x25d0 [mlx5_core] [ 778.349688] ? napi_gro_flush+0x26c/0x3c0 [ 778.350641] napi_complete_done+0x188/0x6b0 [ 778.351627] mlx5e_napi_poll+0x373/0x1b80 [mlx5_core] [ 778.352853] __napi_poll+0x9f/0x510 [ 778.353704] ? mlx5_flow_namespace_set_mode+0x260/0x260 [mlx5_core] [ 778.355158] net_rx_action+0x34c/0xa40 [ 778.356060] ? napi_threaded_poll+0x3d0/0x3d0 [ 778.357083] ? sched_clock_cpu+0x18/0x190 [ 778.358041] ? __common_interrupt+0x8e/0x1a0 [ 778.359045] __do_softirq+0x1ce/0x984 [ 778.359938] __irq_exit_rcu+0x137/0x1d0 [ 778.360865] irq_exit_rcu+0xa/0x20 [ 778.361708] common_interrupt+0x80/0xa0 [ 778.362640] </IRQ> [ 778.363212] asm_common_interrupt+0x1e/0x40 [ 778.364204] RIP: 0010:native_safe_halt+0xe/0x10 [ 778.365273] Code: 4f ff ff ff 4c 89 e7 e8 50 3f 40 fe e9 dc fe ff ff 48 89 df e8 43 3f 40 fe eb 90 cc e9 07 00 00 00 0f 00 2d 74 05 62 00 fb f4 <c3> 90 e9 07 00 00 00 0f 00 2d 64 05 62 00 f4 c3 cc cc 0f 1f 44 00 [ 778.369355] RSP: 0018:ffffffff84407e48 EFLAGS: 00000246 [ 778.370570] RAX: ffff88842de46a80 RBX: ffffffff84425840 RCX: ffffffff83418468 [ 778.372143] RDX: 000000000026f1da RSI: 0000000000000004 RDI: ffffffff8343af5e [ 778.373722] RBP: fffffbfff0884b08 R08: 0000000000000000 R09: ffff88842de46bcb [ 778.375292] R10: ffffed1085bc8d79 R11: 0000000000000001 R12: 0000000000000000 [ 778.376860] R13: ffffffff851124a0 R14: 0000000000000000 R15: dffffc0000000000 [ 778.378491] ? rcu_eqs_enter.constprop.0+0xb8/0xe0 [ 778.379606] ? default_idle_call+0x5e/0xe0 [ 778.380578] default_idle+0xa/0x10 [ 778.381406] default_idle_call+0x96/0xe0 [ 778.382350] do_idle+0x3d4/0x550 [ 778.383153] ? arch_cpu_idle_exit+0x40/0x40 [ 778.384143] cpu_startup_entry+0x19/0x20 [ 778.385078] start_kernel+0x3c7/0x3e5 [ 778.385978] secondary_startup_64_no_verify+0xb0/0xbb Fix the issue by providing new function tc_skb_ext_alloc() that allocates tc skb extension and initializes its memory to 0 before returning it to the caller. Change all existing users to use new API instead of calling skb_ext_add() directly. Fixes: 038ebb1a713d ("net/sched: act_ct: fix miss set mru for ovs after defrag in act_ct") Fixes: d29334c15d33 ("net/sched: act_api: fix miss set post_ct for ovs after do conntrack in act_ct") Signed-off-by: Vlad Buslov <vladbu@nvidia.com> --- Notes: Changes V1 -> V2: - Create a wrapper for tc skb extension allocation instead of modifying skb_ext_add() - suggested by Florian Westphal. drivers/net/ethernet/mellanox/mlx5/core/en/rep/tc.c | 2 +- drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 2 +- include/net/pkt_cls.h | 11 +++++++++++ net/sched/cls_api.c | 2 +- 4 files changed, 14 insertions(+), 3 deletions(-)