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  1. 29 Oct, 2016 34 commits
  3. 28 Oct, 2016 3 commits
  5. 27 Oct, 2016 3 commits
    • Jamal Hadi Salim's avatar
      net sched filters: fix notification of filter delete with proper handle · 9ee78374
      Jamal Hadi Salim authored 
      Daniel says:

While trying out [1][2], I noticed that tc monitor doesn't show the
correct handle on delete:

$ tc monitor
qdisc clsact ffff: dev eno1 parent ffff:fff1
filter dev eno1 ingress protocol all pref 49152 bpf handle 0x2a [...]
deleted filter dev eno1 ingress protocol all pref 49152 bpf handle 0xf3be0c80

some context to explain the above:
The user identity of any tc filter is represented by a 32-bit
identifier encoded in tcm->tcm_handle. Example 0x2a in the bpf filter
above. A user wishing to delete, get or even modify a specific filter
uses this handle to reference it.
Every classifier is free to provide its own semantics for the 32 bit handle.
Example: classifiers like u32 use schemes like 800:1:801 to describe
the semantics of their filters represented as hash table, bucket and
node ids etc.
Classifiers also have internal per-filter representation which is different
from this externally visible identity. Most classifiers set this
internal representation to be a pointer address (which allows fast retrieval
of said filters in their implementations). This internal representation
is referenced with the "fh" variable in the kernel control code.

When a user successfuly deletes a specific filter, by specifying the correct
tcm->tcm_handle, an event is generated to user space which indicates
which specific filter was deleted.

Before this patch, the "fh" value was sent to user space as the identity.
As an example what is shown in the sample bpf filter delete event above
is 0xf3be0c80. This is infact a 32-bit truncation of 0xffff8807f3be0c80
which happens to be a 64-bit memory address of the internal filter
representation (address of the corresponding filter's struct cls_bpf_prog);

After this patch the appropriate user identifiable handle as encoded
in the originating request tcm->tcm_handle is generated in the event.
One of the cardinal rules of netlink rules is to be able to take an
event (such as a delete in this case) and reflect it back to the
kernel and successfully delete the filter. This patch achieves that.

Note, this issue has existed since the original TC action
infrastructure code patch back in 2004 as found in:
https://git.kernel.org/cgit/linux/kernel/git/history/history.git/commit/

[1] http://patchwork.ozlabs.org/patch/682828/
[2] http://patchwork.ozlabs.org/patch/682829/

Fixes: 4e54c481 ("[NET]: Add tc extensions infrastructure.")
Reported-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: default avatarJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      9ee78374
    • Colin Ian King's avatar
      net: bgmac: fix spelling mistake: "connecton" -> "connection" · c121f72a
      Colin Ian King authored 
      trivial fix to spelling mistake in dev_err message
Signed-off-by: default avatarColin Ian King <colin.king@canonical.com>
Acked-by: default avatarJon Mason <jon.mason@broadcom.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c121f72a
    • Arnd Bergmann's avatar
      flow_dissector: fix vlan tag handling · bc72f3dd
      Arnd Bergmann authored 
      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: 3805a938 ("flow_dissector: Check skb for VLAN only if skb specified.")
Fixes: d5709f7a ("flow_dissector: For stripped vlan, get vlan info from skb->vlan_tci")
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarJiri Pirko <jiri@mellanox.com>
Acked-by: default avatarEric Garver <e@erig.me>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      bc72f3dd
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