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sock_diag: allow to dump bpf filters

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This patch allows to dump BPF filters attached to a socket with
SO_ATTACH_FILTER.
Note that we check CAP_SYS_ADMIN before allowing to dump this info.

For now, only AF_PACKET sockets use this feature.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Nicolas Dichtel 2013-04-25 06:53:54 +00:00 committed by David S. Miller
parent 76d0eeb1a1
commit e8d9612c18
4 changed files with 42 additions and 0 deletions
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3
include/linux/sock_diag.h
View file

@ -1,6 +1,7 @@
#ifndef __SOCK_DIAG_H__
#define __SOCK_DIAG_H__
#include <linux/user_namespace.h>
#include <uapi/linux/sock_diag.h>
struct sk_buff;
@ -22,5 +23,7 @@ int sock_diag_check_cookie(void *sk, __u32 *cookie);
void sock_diag_save_cookie(void *sk, __u32 *cookie);
int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attr);
int sock_diag_put_filterinfo(struct user_namespace *user_ns, struct sock *sk,
struct sk_buff *skb, int attrtype);
#endif

2
include/uapi/linux/packet_diag.h
View file

@ -17,6 +17,7 @@ struct packet_diag_req {
#define PACKET_SHOW_RING_CFG 0x00000004 /* Rings configuration parameters */
#define PACKET_SHOW_FANOUT 0x00000008
#define PACKET_SHOW_MEMINFO 0x00000010
#define PACKET_SHOW_FILTER 0x00000020
struct packet_diag_msg {
__u8 pdiag_family;
@ -35,6 +36,7 @@ enum {
PACKET_DIAG_FANOUT,
PACKET_DIAG_UID,
PACKET_DIAG_MEMINFO,
PACKET_DIAG_FILTER,
__PACKET_DIAG_MAX,
};

33
net/core/sock_diag.c
View file

@ -49,6 +49,39 @@ int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attrtype)
}
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 sk_filter *filter;
unsigned int len;
int err = 0;
if (!ns_capable(user_ns, CAP_NET_ADMIN)) {
nla_reserve(skb, attrtype, 0);
return 0;
}
rcu_read_lock();
filter = rcu_dereference(sk->sk_filter);
len = filter ? filter->len * sizeof(struct sock_filter) : 0;
attr = nla_reserve(skb, attrtype, len);
if (attr == NULL) {
err = -EMSGSIZE;
goto out;
}
if (filter)
memcpy(nla_data(attr), filter->insns, len);
out:
rcu_read_unlock();
return err;
}
EXPORT_SYMBOL(sock_diag_put_filterinfo);
void sock_diag_register_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
{
mutex_lock(&sock_diag_table_mutex);

4
net/packet/diag.c
View file

@ -170,6 +170,10 @@ static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,
sock_diag_put_meminfo(sk, skb, PACKET_DIAG_MEMINFO))
goto out_nlmsg_trim;
if ((req->pdiag_show & PACKET_SHOW_FILTER) &&
sock_diag_put_filterinfo(user_ns, sk, skb, PACKET_DIAG_FILTER))
goto out_nlmsg_trim;
return nlmsg_end(skb, nlh);
out_nlmsg_trim: