linux-toradex.git/net/core/flow_dissector.c, branch v4.9.90

flow_dissector: properly cap thoff field

2018-01-31T11:55:56+00:00

[ Upstream commit d0c081b49137cd3200f2023c0875723be66e7ce5 ]

syzbot reported yet another crash [1] that is caused by
insufficient validation of DODGY packets.

Two bugs are happening here to trigger the crash.

1) Flow dissection leaves with incorrect thoff field.

2) skb_probe_transport_header() sets transport header to this invalid
thoff, even if pointing after skb valid data.

3) qdisc_pkt_len_init() reads out-of-bound data because it
trusts tcp_hdrlen(skb)

Possible fixes :

- Full flow dissector validation before injecting bad DODGY packets in
the stack.
 This approach was attempted here : https://patchwork.ozlabs.org/patch/
861874/

- Have more robust functions in the core.
  This might be needed anyway for stable versions.

This patch fixes the flow dissection issue.

[1]
CPU: 1 PID: 3144 Comm: syzkaller271204 Not tainted 4.15.0-rc4-mm1+ #49
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:355 [inline]
 kasan_report+0x23b/0x360 mm/kasan/report.c:413
 __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:432
 __tcp_hdrlen include/linux/tcp.h:35 [inline]
 tcp_hdrlen include/linux/tcp.h:40 [inline]
 qdisc_pkt_len_init net/core/dev.c:3160 [inline]
 __dev_queue_xmit+0x20d3/0x2200 net/core/dev.c:3465
 dev_queue_xmit+0x17/0x20 net/core/dev.c:3554
 packet_snd net/packet/af_packet.c:2943 [inline]
 packet_sendmsg+0x3ad5/0x60a0 net/packet/af_packet.c:2968
 sock_sendmsg_nosec net/socket.c:628 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:638
 sock_write_iter+0x31a/0x5d0 net/socket.c:907
 call_write_iter include/linux/fs.h:1776 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x684/0x970 fs/read_write.c:482
 vfs_write+0x189/0x510 fs/read_write.c:544
 SYSC_write fs/read_write.c:589 [inline]
 SyS_write+0xef/0x220 fs/read_write.c:581
 entry_SYSCALL_64_fastpath+0x1f/0x96

Fixes: 34fad54c2537 ("net: __skb_flow_dissect() must cap its return value")
Fixes: a6e544b0a88b ("flow_dissector: Jump to exit code in __skb_flow_dissect")
Signed-off-by: Eric Dumazet 
Cc: Willem de Bruijn 
Reported-by: syzbot 
Acked-by: Jason Wang 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

flow_dissector: Update pptp handling to avoid null pointer deref.

2017-01-15T12:42:54+00:00

[ Upstream commit d0af683407a26a4437d8fa6e283ea201f2ae8146 ]

__skb_flow_dissect can be called with a skb or a data packet, either
can be NULL. All calls seems to have been moved to __skb_header_pointer
except the pptp handling which is still calling skb_header_pointer.

skb_header_pointer will use skb->data and thus:
[  109.556866] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080
[  109.557102] IP: [] __skb_flow_dissect+0xa88/0xce0
[  109.557263] PGD 0
[  109.557338]
[  109.557484] Oops: 0000 [#1] SMP
[  109.557562] Modules linked in: chaoskey
[  109.557783] CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.9.0 #79
[  109.557867] Hardware name: Supermicro A1SRM-LN7F/LN5F/A1SRM-LN7F-2758, BIOS 1.0c 11/04/2015
[  109.557957] task: ffff94085c27bc00 task.stack: ffffb745c0068000
[  109.558041] RIP: 0010:[]  [] __skb_flow_dissect+0xa88/0xce0
[  109.558203] RSP: 0018:ffff94087fc83d40  EFLAGS: 00010206
[  109.558286] RAX: 0000000000000130 RBX: ffffffff8975bf80 RCX: ffff94084fab6800
[  109.558373] RDX: 0000000000000010 RSI: 000000000000000c RDI: 0000000000000000
[  109.558460] RBP: 0000000000000b88 R08: 0000000000000000 R09: 0000000000000022
[  109.558547] R10: 0000000000000008 R11: ffff94087fc83e04 R12: 0000000000000000
[  109.558763] R13: ffff94084fab6800 R14: ffff94087fc83e04 R15: 000000000000002f
[  109.558979] FS:  0000000000000000(0000) GS:ffff94087fc80000(0000) knlGS:0000000000000000
[  109.559326] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  109.559539] CR2: 0000000000000080 CR3: 0000000281809000 CR4: 00000000001026e0
[  109.559753] Stack:
[  109.559957]  000000000000000c ffff94084fab6822 0000000000000001 ffff94085c2b5fc0
[  109.560578]  0000000000000001 0000000000002000 0000000000000000 0000000000000000
[  109.561200]  0000000000000000 0000000000000000 0000000000000000 0000000000000000
[  109.561820] Call Trace:
[  109.562027]  
[  109.562108]  [] ? eth_get_headlen+0x7a/0xf0
[  109.562522]  [] ? igb_poll+0x96a/0xe80
[  109.562737]  [] ? net_rx_action+0x20b/0x350
[  109.562953]  [] ? __do_softirq+0xe8/0x280
[  109.563169]  [] ? irq_exit+0xaa/0xb0
[  109.563382]  [] ? do_IRQ+0x4b/0xc0
[  109.563597]  [] ? common_interrupt+0x7f/0x7f
[  109.563810]  
[  109.563890]  [] ? cpuidle_enter_state+0x130/0x2c0
[  109.564304]  [] ? cpuidle_enter_state+0x120/0x2c0
[  109.564520]  [] ? cpu_startup_entry+0x19f/0x1f0
[  109.564737]  [] ? start_secondary+0x12a/0x140
[  109.564950] Code: 83 e2 20 a8 80 0f 84 60 01 00 00 c7 04 24 08 00
00 00 66 85 d2 0f 84 be fe ff ff e9 69 fe ff ff 8b 34 24 89 f2 83 c2
04 66 85 c0 <41> 8b 84 24 80 00 00 00 0f 49 d6 41 8d 31 01 d6 41 2b 84
24 84
[  109.569959] RIP  [] __skb_flow_dissect+0xa88/0xce0
[  109.570245]  RSP 
[  109.570453] CR2: 0000000000000080

Fixes: ab10dccb1160 ("rps: Inspect PPTP encapsulated by GRE to get flow hash")
Signed-off-by: Ian Kumlien 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

flow_dissect: call init_default_flow_dissectors() earlier

2016-11-22T19:44:01+00:00

Andre Noll reported panics after my recent fix (commit 34fad54c2537
"net: __skb_flow_dissect() must cap its return value")

After some more headaches, Alexander root caused the problem to
init_default_flow_dissectors() being called too late, in case
a network driver like IGB is not a module and receives DHCP message
very early.

Fix is to call init_default_flow_dissectors() much earlier,
as it is a core infrastructure and does not depend on another
kernel service.

Fixes: 06635a35d13d4 ("flow_dissect: use programable dissector in skb_flow_dissect and friends")
Signed-off-by: Eric Dumazet 
Reported-by: Andre Noll 
Diagnosed-by: Alexander Duyck 
Signed-off-by: David S. Miller

net: __skb_flow_dissect() must cap its return value

2016-11-13T04:41:53+00:00

After Tom patch, thoff field could point past the end of the buffer,
this could fool some callers.

If an skb was provided, skb->len should be the upper limit.
If not, hlen is supposed to be the upper limit.

Fixes: a6e544b0a88b ("flow_dissector: Jump to exit code in __skb_flow_dissect")
Signed-off-by: Eric Dumazet 
Reported-by: Yibin Yang 
Acked-by: Willem de Bruijn 
Acked-by: Alexei Starovoitov 
Signed-off-by: David S. Miller

flow_dissector: fix vlan tag handling

2016-10-27T20:36:03+00:00

gcc warns about an uninitialized pointer dereference in the vlan
priority handling:

net/core/flow_dissector.c: In function '__skb_flow_dissect':
net/core/flow_dissector.c:281:61: error: 'vlan' may be used uninitialized in this function [-Werror=maybe-uninitialized]

As pointed out by Jiri Pirko, the variable is never actually used
without being initialized first as the only way it end up uninitialized
is with skb_vlan_tag_present(skb)==true, and that means it does not
get accessed.

However, the warning hints at some related issues that I'm addressing
here:

- the second check for the vlan tag is different from the first one
  that tests the skb for being NULL first, causing both the warning
  and a possible NULL pointer dereference that was not entirely fixed.
- The same patch that introduced the NULL pointer check dropped an
  earlier optimization that skipped the repeated check of the
  protocol type
- The local '_vlan' variable is referenced through the 'vlan' pointer
  but the variable has gone out of scope by the time that it is
  accessed, causing undefined behavior

Caching the result of the 'skb && skb_vlan_tag_present(skb)' check
in a local variable allows the compiler to further optimize the
later check. With those changes, the warning also disappears.

Fixes: 3805a938a6c2 ("flow_dissector: Check skb for VLAN only if skb specified.")
Fixes: d5709f7ab776 ("flow_dissector: For stripped vlan, get vlan info from skb->vlan_tci")
Signed-off-by: Arnd Bergmann 
Acked-by: Jiri Pirko 
Acked-by: Eric Garver 
Signed-off-by: David S. Miller

flow_dissector: Check skb for VLAN only if skb specified.

2016-10-19T14:35:46+00:00

Fixes a panic when calling eth_get_headlen(). Noticed on i40e driver.

Fixes: d5709f7ab776 ("flow_dissector: For stripped vlan, get vlan info from skb->vlan_tci")
Signed-off-by: Eric Garver 
Reviewed-by: Jakub Sitnicki 
Acked-by: Amir Vadai 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2016-09-12T22:52:44+00:00

Conflicts:
	drivers/net/ethernet/mediatek/mtk_eth_soc.c
	drivers/net/ethernet/qlogic/qed/qed_dcbx.c
	drivers/net/phy/Kconfig

All conflicts were cases of overlapping commits.

Signed-off-by: David S. Miller

rps: flow_dissector: Fix uninitialized flow_keys used in __skb_get_hash possibly

2016-09-02T05:45:03+00:00

The original codes depend on that the function parameters are evaluated from
left to right. But the parameter's evaluation order is not defined in C
standard actually.

When flow_keys_have_l4(&keys) is invoked before ___skb_get_hash(skb, &keys,
hashrnd) with some compilers or environment, the keys passed to
flow_keys_have_l4 is not initialized.

Fixes: 6db61d79c1e1 ("flow_dissector: Ignore flow dissector return value from ___skb_get_hash")

Acked-by: Eric Dumazet 
Signed-off-by: Gao Feng 
Signed-off-by: David S. Miller

flow_dissector: Get vlan priority in addition to vlan id

2016-08-19T06:13:13+00:00

Add vlan priority check to the flow dissector by adding new flow
dissector struct, flow_dissector_key_vlan which includes vlan tag
fields.

vlan_id and flow_label fields were under the same struct
(flow_dissector_key_tags). It was a convenient setting since struct
flow_dissector_key_tags is used by struct flow_keys and by setting
vlan_id and flow_label under the same struct, we get precisely 24 or 48
bytes in flow_keys from flow_dissector_key_basic.

Now, when adding vlan priority support, the code will be cleaner if
flow_label and vlan tag won't be under the same struct anymore.

Signed-off-by: Hadar Hen Zion 
Acked-by: Jiri Pirko 
Signed-off-by: David S. Miller

flow_dissector: For stripped vlan, get vlan info from skb->vlan_tci

2016-08-19T06:13:13+00:00

Early in the datapath skb_vlan_untag function is called, stripped
the vlan from the skb and set skb->vlan_tci and skb->vlan_proto fields.

The current dissection doesn't handle stripped vlan packets correctly.
In some flows, vlan doesn't exist in skb->data anymore when applying
flow dissection on the skb, fix that.

In case vlan info wasn't stripped before applying flow_dissector (RPS
flow for example), or in case of skb with multiple vlans (e.g. 802.1ad),
get the vlan info from skb->data. The flow_dissector correctly skips
any number of vlans and stores only the first level vlan.

Fixes: 0744dd00c1b1 ('net: introduce skb_flow_dissect()')
Signed-off-by: Hadar Hen Zion 
Acked-by: Jiri Pirko 
Signed-off-by: David S. Miller