Re: [PATCH net] net/sched: fix NULL dereference in the error path of tcf_vlan_init()

[Davide Caratti]

On Thu, 2018-03-15 at 15:29 +0100, Davide Caratti wrote:
> On Thu, 2018-03-15 at 15:21 +0100, Jiri Pirko wrote:
> ...
> 
> > Acked-by: Jiri Pirko 
> 
> thank you for reviewing!
> 
> apparently, also act_tunnel_key seem and act_csum have a similar problem.
> I will check and eventually do a followup series this afternoon.
> 
> thank you,
> regards

hello David,

please drop this patch: after some tests, the following TC actions are
affected by the same problem:

act_vlan
act_csum
act_tunnel_key
act_skbmod
act_sample

so, I'm posting right now a series that fixes all of them.

In act_ife and act_bpf, the problem is potentially there, but we don't see
it crashing yet because we don't call tcf_idr_release() on the error
path. 
This is causing the leak of 'index', and will be fixed in another series
tomorrow.

thank you in advance,
regards
-- 
davide

Re: [PATCH net] net/sched: fix NULL dereference in the error path of tcf_vlan_init()

[Davide Caratti]

On Thu, 2018-03-15 at 15:21 +0100, Jiri Pirko wrote:
...

> Acked-by: Jiri Pirko 

thank you for reviewing!

apparently, also act_tunnel_key seem and act_csum have a similar problem.
I will check and eventually do a followup series this afternoon.

thank you,
regards
-- 
davide

Re: [PATCH net] net/sched: fix NULL dereference in the error path of tcf_vlan_init()

[Roman Mashak]

Davide Caratti  writes:

> when the following command
>
>  # tc actions replace action vlan pop index 100
>
> is run for the first time, and tcf_vlan_init() fails allocating struct
> tcf_vlan_params, tcf_vlan_cleanup() calls kfree_rcu(NULL, ...). This causes
> the following error:
>

[...]

> fix this in tcf_vlan_cleanup(), ensuring that kfree_rcu(p, ...) is called
> only when p is not NULL.
>
> Fixes: 4c5b9d9642c8 ("act_vlan: VLAN action rewrite to use RCU lock/unlock 
> and update")
> Signed-off-by: Davide Caratti 
> ---
>  net/sched/act_vlan.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/net/sched/act_vlan.c b/net/sched/act_vlan.c
> index e1a1b3f3983a..c2914e9a4a6f 100644
> --- a/net/sched/act_vlan.c
> +++ b/net/sched/act_vlan.c
> @@ -225,7 +225,8 @@ static void tcf_vlan_cleanup(struct tc_action *a)
>   struct tcf_vlan_params *p;
>  
>   p = rcu_dereference_protected(v->vlan_p, 1);
> - kfree_rcu(p, rcu);
> + if (p)
> + kfree_rcu(p, rcu);
>  }
>  
>  static int tcf_vlan_dump(struct sk_buff *skb, struct tc_action *a,

Good catch. I think you can propagate the fix on the other actions
->cleanup(), where private parameters structure may not be present at
cleanup time, e.g. csum, ife.

Re: [PATCH net] net/sched: fix NULL dereference in the error path of tcf_vlan_init()

[Jiri Pirko]

Thu, Mar 15, 2018 at 03:06:30PM CET, dcara...@redhat.com wrote:
>when the following command
>
> # tc actions replace action vlan pop index 100
>
>is run for the first time, and tcf_vlan_init() fails allocating struct
>tcf_vlan_params, tcf_vlan_cleanup() calls kfree_rcu(NULL, ...). This causes
>the following error:
>
> BUG: unable to handle kernel NULL pointer dereference at 0018
> IP: __call_rcu+0x23/0x2b0
> PGD 8000760a2067 P4D 8000760a2067 PUD 742c1067 PMD 0
> Oops: 0002 [#1] SMP PTI
> Modules linked in: act_vlan(E) ip6table_filter ip6_tables iptable_filter 
> binfmt_misc ext4 snd_hda_codec_generic snd_hda_intel mbcache snd_hda_codec 
> jbd2 snd_hda_core crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc 
> snd_hwdep snd_seq snd_seq_device snd_pcm aesni_intel crypto_simd snd_timer 
> glue_helper snd cryptd joydev soundcore virtio_balloon pcspkr 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 drm virtio_console virtio_blk virtio_net ata_piix crc32c_intel libata 
> virtio_pci i2c_core virtio_ring serio_raw virtio floppy dm_mirror 
> dm_region_hash dm_log dm_mod [last unloaded: act_vlan]
> CPU: 3 PID: 3119 Comm: tc Tainted: GE
> 4.16.0-rc4.act_vlan.orig+ #403
> Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
> RIP: 0010:__call_rcu+0x23/0x2b0
> RSP: 0018:aac3005fb798 EFLAGS: 00010246
> RAX: c0704080 RBX: 97f2b4bbe900 RCX: 
> RDX: abca5f00 RSI: 0010 RDI: 0010
> RBP: 0010 R08: 0001 R09: 0044
> R10: fd003000 R11: 97f2faab5b91 R12: 
> R13: abca5f00 R14: 97f2fb80202c R15: fff4
> FS:  7f68f75b4740() GS:97f2ffd8() knlGS:
> CS:  0010 DS:  ES:  CR0: 80050033
> CR2: 0018 CR3: 72b52001 CR4: 001606e0
> Call Trace:
>  __tcf_idr_release+0x79/0xf0
>  tcf_vlan_init+0x168/0x270 [act_vlan]
>  tcf_action_init_1+0x2cc/0x430
>  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.28+0x100/0x100
>  netlink_rcv_skb+0xd2/0x110
>  netlink_unicast+0x17c/0x230
>  netlink_sendmsg+0x2cd/0x3c0
>  sock_sendmsg+0x30/0x40
>  ___sys_sendmsg+0x27a/0x290
>  ? filemap_map_pages+0x34a/0x3a0
>  ? __handle_mm_fault+0xbfd/0xe20
>  __sys_sendmsg+0x51/0x90
>  do_syscall_64+0x6e/0x1a0
>  entry_SYSCALL_64_after_hwframe+0x3d/0xa2
> RIP: 0033:0x7f68f69c5ba0
> RSP: 002b:7fffd79c1118 EFLAGS: 0246 ORIG_RAX: 002e
> RAX: ffda RBX: 7fffd79c1240 RCX: 7f68f69c5ba0
> RDX:  RSI: 7fffd79c1190 RDI: 0003
> RBP: 5aaa708e R08: 0002 R09: 
> R10: 7fffd79c0ba0 R11: 0246 R12: 
> R13: 7fffd79c1254 R14: 0001 R15: 00669f60
> Code: 5d e9 42 da ff ff 66 90 0f 1f 44 00 00 41 57 41 56 41 55 49 89 d5 41 54 
> 55 48 89 fd 53 48 83 ec 08 40 f6 c7 07 0f 85 19 02 00 00 <48> 89 75 08 48 c7 
> 45 00 00 00 00 00 9c 58 0f 1f 44 00 00 49 89
> RIP: __call_rcu+0x23/0x2b0 RSP: aac3005fb798
> CR2: 0018
>
>fix this in tcf_vlan_cleanup(), ensuring that kfree_rcu(p, ...) is called
>only when p is not NULL.
>
>Fixes: 4c5b9d9642c8 ("act_vlan: VLAN action rewrite to use RCU lock/unlock and 
>update")
>Signed-off-by: Davide Caratti 

Acked-by: Jiri Pirko 

[PATCH net] net/sched: fix NULL dereference in the error path of tcf_vlan_init()

[Davide Caratti]

when the following command

 # tc actions replace action vlan pop index 100

is run for the first time, and tcf_vlan_init() fails allocating struct
tcf_vlan_params, tcf_vlan_cleanup() calls kfree_rcu(NULL, ...). This causes
the following error:

 BUG: unable to handle kernel NULL pointer dereference at 0018
 IP: __call_rcu+0x23/0x2b0
 PGD 8000760a2067 P4D 8000760a2067 PUD 742c1067 PMD 0
 Oops: 0002 [#1] SMP PTI
 Modules linked in: act_vlan(E) ip6table_filter ip6_tables iptable_filter 
binfmt_misc ext4 snd_hda_codec_generic snd_hda_intel mbcache snd_hda_codec jbd2 
snd_hda_core crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc snd_hwdep 
snd_seq snd_seq_device snd_pcm aesni_intel crypto_simd snd_timer glue_helper 
snd cryptd joydev soundcore virtio_balloon pcspkr 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 drm 
virtio_console virtio_blk virtio_net ata_piix crc32c_intel libata virtio_pci 
i2c_core virtio_ring serio_raw virtio floppy dm_mirror dm_region_hash dm_log 
dm_mod [last unloaded: act_vlan]
 CPU: 3 PID: 3119 Comm: tc Tainted: GE4.16.0-rc4.act_vlan.orig+ 
#403
 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
 RIP: 0010:__call_rcu+0x23/0x2b0
 RSP: 0018:aac3005fb798 EFLAGS: 00010246
 RAX: c0704080 RBX: 97f2b4bbe900 RCX: 
 RDX: abca5f00 RSI: 0010 RDI: 0010
 RBP: 0010 R08: 0001 R09: 0044
 R10: fd003000 R11: 97f2faab5b91 R12: 
 R13: abca5f00 R14: 97f2fb80202c R15: fff4
 FS:  7f68f75b4740() GS:97f2ffd8() knlGS:
 CS:  0010 DS:  ES:  CR0: 80050033
 CR2: 0018 CR3: 72b52001 CR4: 001606e0
 Call Trace:
  __tcf_idr_release+0x79/0xf0
  tcf_vlan_init+0x168/0x270 [act_vlan]
  tcf_action_init_1+0x2cc/0x430
  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.28+0x100/0x100
  netlink_rcv_skb+0xd2/0x110
  netlink_unicast+0x17c/0x230
  netlink_sendmsg+0x2cd/0x3c0
  sock_sendmsg+0x30/0x40
  ___sys_sendmsg+0x27a/0x290
  ? filemap_map_pages+0x34a/0x3a0
  ? __handle_mm_fault+0xbfd/0xe20
  __sys_sendmsg+0x51/0x90
  do_syscall_64+0x6e/0x1a0
  entry_SYSCALL_64_after_hwframe+0x3d/0xa2
 RIP: 0033:0x7f68f69c5ba0
 RSP: 002b:7fffd79c1118 EFLAGS: 0246 ORIG_RAX: 002e
 RAX: ffda RBX: 7fffd79c1240 RCX: 7f68f69c5ba0
 RDX:  RSI: 7fffd79c1190 RDI: 0003
 RBP: 5aaa708e R08: 0002 R09: 
 R10: 7fffd79c0ba0 R11: 0246 R12: 
 R13: 7fffd79c1254 R14: 0001 R15: 00669f60
 Code: 5d e9 42 da ff ff 66 90 0f 1f 44 00 00 41 57 41 56 41 55 49 89 d5 41 54 
55 48 89 fd 53 48 83 ec 08 40 f6 c7 07 0f 85 19 02 00 00 <48> 89 75 08 48 c7 45 
00 00 00 00 00 9c 58 0f 1f 44 00 00 49 89
 RIP: __call_rcu+0x23/0x2b0 RSP: aac3005fb798
 CR2: 0018

fix this in tcf_vlan_cleanup(), ensuring that kfree_rcu(p, ...) is called
only when p is not NULL.

Fixes: 4c5b9d9642c8 ("act_vlan: VLAN action rewrite to use RCU lock/unlock and 
update")
Signed-off-by: Davide Caratti 
---
 net/sched/act_vlan.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/sched/act_vlan.c b/net/sched/act_vlan.c
index e1a1b3f3983a..c2914e9a4a6f 100644
--- a/net/sched/act_vlan.c
+++ b/net/sched/act_vlan.c
@@ -225,7 +225,8 @@ static void tcf_vlan_cleanup(struct tc_action *a)
struct tcf_vlan_params *p;
 
p = rcu_dereference_protected(v->vlan_p, 1);
-   kfree_rcu(p, rcu);
+   if (p)
+   kfree_rcu(p, rcu);
 }
 
 static int tcf_vlan_dump(struct sk_buff *skb, struct tc_action *a,
-- 
2.14.3