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author | Daniel Borkmann <dborkman@redhat.com> | 2014-03-28 18:58:19 +0100 |
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committer | David S. Miller <davem@davemloft.net> | 2014-03-31 00:45:09 -0400 |
commit | a3ea269b8bcdbb0c5fa2fd449a436e7987446975 (patch) | |
tree | 9e118e381c14f9a065cc4136be2a9bf6e5257dfb /net/core/sock_diag.c | |
parent | f8bbbfc3b97f4c7a6c7c23185e520b22bfc3a21d (diff) | |
download | linux-stable-a3ea269b8bcdbb0c5fa2fd449a436e7987446975.tar.gz linux-stable-a3ea269b8bcdbb0c5fa2fd449a436e7987446975.tar.bz2 linux-stable-a3ea269b8bcdbb0c5fa2fd449a436e7987446975.zip |
net: filter: keep original BPF program around
In order to open up the possibility to internally transform a BPF program
into an alternative and possibly non-trivial reversible representation, we
need to keep the original BPF program around, so that it can be passed back
to user space w/o the need of a complex decoder.
The reason for that use case resides in commit a8fc92778080 ("sk-filter:
Add ability to get socket filter program (v2)"), that is, the ability
to retrieve the currently attached BPF filter from a given socket used
mainly by the checkpoint-restore project, for example.
Therefore, we add two helpers sk_{store,release}_orig_filter for taking
care of that. In the sk_unattached_filter_create() case, there's no such
possibility/requirement to retrieve a loaded BPF program. Therefore, we
can spare us the work in that case.
This approach will simplify and slightly speed up both, sk_get_filter()
and sock_diag_put_filterinfo() handlers as we won't need to successively
decode filters anymore through sk_decode_filter(). As we still need
sk_decode_filter() later on, we're keeping it around.
Joint work with Alexei Starovoitov.
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/sock_diag.c')
-rw-r--r-- | net/core/sock_diag.c | 23 |
1 files changed, 10 insertions, 13 deletions
diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c index a0e9cf6379de..d7af18859322 100644 --- a/net/core/sock_diag.c +++ b/net/core/sock_diag.c @@ -52,9 +52,10 @@ EXPORT_SYMBOL_GPL(sock_diag_put_meminfo); int sock_diag_put_filterinfo(struct user_namespace *user_ns, struct sock *sk, struct sk_buff *skb, int attrtype) { - struct nlattr *attr; + struct sock_fprog_kern *fprog; struct sk_filter *filter; - unsigned int len; + struct nlattr *attr; + unsigned int flen; int err = 0; if (!ns_capable(user_ns, CAP_NET_ADMIN)) { @@ -63,24 +64,20 @@ int sock_diag_put_filterinfo(struct user_namespace *user_ns, struct sock *sk, } rcu_read_lock(); - filter = rcu_dereference(sk->sk_filter); - len = filter ? filter->len * sizeof(struct sock_filter) : 0; + if (!filter) + goto out; - attr = nla_reserve(skb, attrtype, len); + fprog = filter->orig_prog; + flen = sk_filter_proglen(fprog); + + attr = nla_reserve(skb, attrtype, flen); if (attr == NULL) { err = -EMSGSIZE; goto out; } - if (filter) { - struct sock_filter *fb = (struct sock_filter *)nla_data(attr); - int i; - - for (i = 0; i < filter->len; i++, fb++) - sk_decode_filter(&filter->insns[i], fb); - } - + memcpy(nla_data(attr), fprog->filter, flen); out: rcu_read_unlock(); return err; |