From e8d9612c181b1a68ba5f71384629343466f1bd13 Mon Sep 17 00:00:00 2001 From: Nicolas Dichtel Date: Thu, 25 Apr 2013 06:53:54 +0000 Subject: sock_diag: allow to dump bpf filters 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 Signed-off-by: David S. Miller --- include/linux/sock_diag.h | 3 +++ include/uapi/linux/packet_diag.h | 2 ++ net/core/sock_diag.c | 33 +++++++++++++++++++++++++++++++++ net/packet/diag.c | 4 ++++ 4 files changed, 42 insertions(+) diff --git a/include/linux/sock_diag.h b/include/linux/sock_diag.h index e8d702e..54f91d3 100644 --- a/include/linux/sock_diag.h +++ b/include/linux/sock_diag.h @@ -1,6 +1,7 @@ #ifndef __SOCK_DIAG_H__ #define __SOCK_DIAG_H__ +#include #include 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 diff --git a/include/uapi/linux/packet_diag.h b/include/uapi/linux/packet_diag.h index c0802c1..b2cc0cd 100644 --- a/include/uapi/linux/packet_diag.h +++ b/include/uapi/linux/packet_diag.h @@ -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, }; diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c index a29e90c..d5bef0b0 100644 --- a/net/core/sock_diag.c +++ b/net/core/sock_diag.c @@ -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); diff --git a/net/packet/diag.c b/net/packet/diag.c index 822fe9b..a9584a2 100644 --- a/net/packet/diag.c +++ b/net/packet/diag.c @@ -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: -- cgit v1.1