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  1. 27 1月, 2015 2 次提交
    • D
      net: cls_bpf: fix auto generation of per list handles · 3f2ab135
      由 Daniel Borkmann 提交于 
      When creating a bpf classifier in tc with priority collisions and
invoking automatic unique handle assignment, cls_bpf_grab_new_handle()
will return a wrong handle id which in fact is non-unique. Usually
altering of specific filters is being addressed over major id, but
in case of collisions we result in a filter chain, where handle ids
address individual cls_bpf_progs inside the classifier.

Issue is, in cls_bpf_grab_new_handle() we probe for head->hgen handle
in cls_bpf_get() and in case we found a free handle, we're supposed
to use exactly head->hgen. In case of insufficient numbers of handles,
we bail out later as handle id 0 is not allowed.

Fixes: 7d1d65cb ("net: sched: cls_bpf: add BPF-based classifier")
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Acked-by: NJiri Pirko <jiri@resnulli.us>
Acked-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      3f2ab135
    • D
      net: cls_bpf: fix size mismatch on filter preparation · 7913ecf6
      由 Daniel Borkmann 提交于 
      In cls_bpf_modify_existing(), we read out the number of filter blocks,
do some sanity checks, allocate a block on that size, and copy over the
BPF instruction blob from user space, then pass everything through the
classic BPF checker prior to installation of the classifier.

We should reject mismatches here, there are 2 scenarios: the number of
filter blocks could be smaller than the provided instruction blob, so
we do a partial copy of the BPF program, and thus the instructions will
either be rejected from the verifier or a valid BPF program will be run;
in the other case, we'll end up copying more than we're supposed to,
and most likely the trailing garbage will be rejected by the verifier
as well (i.e. we need to fit instruction pattern, ret {A,K} needs to be
last instruction, load/stores must be correct, etc); in case not, we
would leak memory when dumping back instruction patterns. The code should
have only used nla_len() as Dave noted to avoid this from the beginning.
Anyway, lets fix it by rejecting such load attempts.

Fixes: 7d1d65cb ("net: sched: cls_bpf: add BPF-based classifier")
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Acked-by: NJiri Pirko <jiri@resnulli.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      7913ecf6
  3. 18 1月, 2015 1 次提交
  5. 10 12月, 2014 1 次提交
  7. 09 12月, 2014 2 次提交
  9. 07 10月, 2014 1 次提交
    • J
      net: sched: do not use tcf_proto 'tp' argument from call_rcu · 18cdb37e
      由 John Fastabend 提交于 
      Using the tcf_proto pointer 'tp' from inside the classifiers callback
is not valid because it may have been cleaned up by another call_rcu
occuring on another CPU.

'tp' is currently being used by tcf_unbind_filter() in this patch we
move instances of tcf_unbind_filter outside of the call_rcu() context.
This is safe to do because any running schedulers will either read the
valid class field or it will be zeroed.

And all schedulers today when the class is 0 do a lookup using the
same call used by the tcf_exts_bind(). So even if we have a running
classifier hit the null class pointer it will do a lookup and get
to the same result. This is particularly fragile at the moment because
the only way to verify this is to audit the schedulers call sites.
Reported-by: NCong Wang <xiyou.wangconf@gmail.com>
Signed-off-by: NJohn Fastabend <john.r.fastabend@intel.com>
Acked-by: NCong Wang <cwang@twopensource.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      18cdb37e
  11. 29 9月, 2014 1 次提交
  13. 16 9月, 2014 1 次提交
  15. 14 9月, 2014 2 次提交
  17. 03 8月, 2014 1 次提交
    • A
      net: filter: split 'struct sk_filter' into socket and bpf parts · 7ae457c1
      由 Alexei Starovoitov 提交于 
      clean up names related to socket filtering and bpf in the following way:
- everything that deals with sockets keeps 'sk_*' prefix
- everything that is pure BPF is changed to 'bpf_*' prefix

split 'struct sk_filter' into
struct sk_filter {
	atomic_t        refcnt;
	struct rcu_head rcu;
	struct bpf_prog *prog;
};
and
struct bpf_prog {
        u32                     jited:1,
                                len:31;
        struct sock_fprog_kern  *orig_prog;
        unsigned int            (*bpf_func)(const struct sk_buff *skb,
                                            const struct bpf_insn *filter);
        union {
                struct sock_filter      insns[0];
                struct bpf_insn         insnsi[0];
                struct work_struct      work;
        };
};
so that 'struct bpf_prog' can be used independent of sockets and cleans up
'unattached' bpf use cases

split SK_RUN_FILTER macro into:
    SK_RUN_FILTER to be used with 'struct sk_filter *' and
    BPF_PROG_RUN to be used with 'struct bpf_prog *'

__sk_filter_release(struct sk_filter *) gains
__bpf_prog_release(struct bpf_prog *) helper function

also perform related renames for the functions that work
with 'struct bpf_prog *', since they're on the same lines:

sk_filter_size -> bpf_prog_size
sk_filter_select_runtime -> bpf_prog_select_runtime
sk_filter_free -> bpf_prog_free
sk_unattached_filter_create -> bpf_prog_create
sk_unattached_filter_destroy -> bpf_prog_destroy
sk_store_orig_filter -> bpf_prog_store_orig_filter
sk_release_orig_filter -> bpf_release_orig_filter
__sk_migrate_filter -> bpf_migrate_filter
__sk_prepare_filter -> bpf_prepare_filter

API for attaching classic BPF to a socket stays the same:
sk_attach_filter(prog, struct sock *)/sk_detach_filter(struct sock *)
and SK_RUN_FILTER(struct sk_filter *, ctx) to execute a program
which is used by sockets, tun, af_packet

API for 'unattached' BPF programs becomes:
bpf_prog_create(struct bpf_prog **)/bpf_prog_destroy(struct bpf_prog *)
and BPF_PROG_RUN(struct bpf_prog *, ctx) to execute a program
which is used by isdn, ppp, team, seccomp, ptp, xt_bpf, cls_bpf, test_bpf
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      7ae457c1
  19. 24 5月, 2014 1 次提交
    • D
      net: filter: let unattached filters use sock_fprog_kern · b1fcd35c
      由 Daniel Borkmann 提交于 
      The sk_unattached_filter_create() API is used by BPF filters that
are not directly attached or related to sockets, and are used in
team, ptp, xt_bpf, cls_bpf, etc. As such all users do their own
internal managment of obtaining filter blocks and thus already
have them in kernel memory and set up before calling into
sk_unattached_filter_create(). As a result, due to __user annotation
in sock_fprog, sparse triggers false positives (incorrect type in
assignment [different address space]) when filters are set up before
passing them to sk_unattached_filter_create(). Therefore, let
sk_unattached_filter_create() API use sock_fprog_kern to overcome
this issue.
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Acked-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      b1fcd35c
  21. 28 4月, 2014 1 次提交
  23. 14 1月, 2014 1 次提交
  25. 19 12月, 2013 2 次提交
  27. 11 12月, 2013 1 次提交
  29. 30 10月, 2013 1 次提交
    • D
      net: sched: cls_bpf: add BPF-based classifier · 7d1d65cb
      由 Daniel Borkmann 提交于 
      This work contains a lightweight BPF-based traffic classifier that can
serve as a flexible alternative to ematch-based tree classification, i.e.
now that BPF filter engine can also be JITed in the kernel. Naturally, tc
actions and policies are supported as well with cls_bpf. Multiple BPF
programs/filter can be attached for a class, or they can just as well be
written within a single BPF program, that's really up to the user how he
wishes to run/optimize the code, e.g. also for inversion of verdicts etc.
The notion of a BPF program's return/exit codes is being kept as follows:

     0: No match
    -1: Select classid given in "tc filter ..." command
  else: flowid, overwrite the default one

As a minimal usage example with iproute2, we use a 3 band prio root qdisc
on a router with sfq each as leave, and assign ssh and icmp bpf-based
filters to band 1, http traffic to band 2 and the rest to band 3. For the
first two bands we load the bytecode from a file, in the 2nd we load it
inline as an example:

echo 1 > /proc/sys/net/core/bpf_jit_enable

tc qdisc del dev em1 root
tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

tc qdisc add dev em1 parent 1:1 sfq perturb 16
tc qdisc add dev em1 parent 1:2 sfq perturb 16
tc qdisc add dev em1 parent 1:3 sfq perturb 16

tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1
tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1
tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2
tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3

BPF programs can be easily created and passed to tc, either as inline
'bytecode' or 'bytecode-file'. There are a couple of front-ends that can
compile opcodes, for example:

1) People familiar with tcpdump-like filters:

   tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf

2) People that want to low-level program their filters or use BPF
   extensions that lack support by libpcap's compiler:

   bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf

   ssh.ops example code:
   ldh [12]
   jne #0x800, drop
   ldb [23]
   jneq #6, drop
   ldh [20]
   jset #0x1fff, drop
   ldxb 4 * ([14] & 0xf)
   ldh [%x + 14]
   jeq #0x16, pass
   ldh [%x + 16]
   jne #0x16, drop
   pass: ret #-1
   drop: ret #0

It was chosen to load bytecode into tc, since the reverse operation,
tc filter list dev em1, is then able to show the exact commands again.
Possible follow-up work could also include a small expression compiler
for iproute2. Tested with the help of bmon. This idea came up during
the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from
Eric Dumazet!
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Cc: Thomas Graf <tgraf@suug.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      7d1d65cb