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net: diag: allow socket bytecode filters to match socket marks

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This allows a privileged process to filter by socket mark when
dumping sockets via INET_DIAG_BY_FAMILY. This is useful on
systems that use mark-based routing such as Android.

The ability to filter socket marks requires CAP_NET_ADMIN, which
is consistent with other privileged operations allowed by the
SOCK_DIAG interface such as the ability to destroy sockets and
the ability to inspect BPF filters attached to packet sockets.

Tested: https://android-review.googlesource.com/261350
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>
Acked-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Lorenzo Colitti 2016-08-24 15:46:26 +09:00 committed by David S. Miller
parent 627cc4add5
commit a52e95abf7
2 changed files with 39 additions and 3 deletions
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6
include/uapi/linux/inet_diag.h
View File

@ -73,6 +73,7 @@ enum {
INET_DIAG_BC_S_COND, INET_DIAG_BC_S_COND,
INET_DIAG_BC_D_COND, INET_DIAG_BC_D_COND,
INET_DIAG_BC_DEV_COND, /* u32 ifindex */ INET_DIAG_BC_DEV_COND, /* u32 ifindex */
INET_DIAG_BC_MARK_COND,
}; };
struct inet_diag_hostcond { struct inet_diag_hostcond {
@ -82,6 +83,11 @@ struct inet_diag_hostcond {
__be32 addr[0]; __be32 addr[0];
}; };
struct inet_diag_markcond {
__u32 mark;
__u32 mask;
};
/* Base info structure. It contains socket identity (addrs/ports/cookie) /* Base info structure. It contains socket identity (addrs/ports/cookie)
* and, alas, the information shown by netstat. */ * and, alas, the information shown by netstat. */
struct inet_diag_msg { struct inet_diag_msg {

36
net/ipv4/inet_diag.c
View File

@ -45,6 +45,7 @@ struct inet_diag_entry {
u16 family; u16 family;
u16 userlocks; u16 userlocks;
u32 ifindex; u32 ifindex;
u32 mark;
}; };
static DEFINE_MUTEX(inet_diag_table_mutex); static DEFINE_MUTEX(inet_diag_table_mutex);
@ -580,6 +581,14 @@ static int inet_diag_bc_run(const struct nlattr *_bc,
yes = 0; yes = 0;
break; break;
} }
case INET_DIAG_BC_MARK_COND: {
struct inet_diag_markcond *cond;
cond = (struct inet_diag_markcond *)(op + 1);
if ((entry->mark & cond->mask) != cond->mark)
yes = 0;
break;
}
} }
if (yes) { if (yes) {
@ -624,6 +633,12 @@ int inet_diag_bc_sk(const struct nlattr *bc, struct sock *sk)
entry.dport = ntohs(inet->inet_dport); entry.dport = ntohs(inet->inet_dport);
entry.ifindex = sk->sk_bound_dev_if; entry.ifindex = sk->sk_bound_dev_if;
entry.userlocks = sk_fullsock(sk) ? sk->sk_userlocks : 0; entry.userlocks = sk_fullsock(sk) ? sk->sk_userlocks : 0;
if (sk_fullsock(sk))
entry.mark = sk->sk_mark;
else if (sk->sk_state == TCP_NEW_SYN_RECV)
entry.mark = inet_rsk(inet_reqsk(sk))->ir_mark;
else
entry.mark = 0;
return inet_diag_bc_run(bc, &entry); return inet_diag_bc_run(bc, &entry);
} }
@ -706,8 +721,17 @@ static bool valid_port_comparison(const struct inet_diag_bc_op *op,
return true; return true;
} }
static int inet_diag_bc_audit(const struct nlattr *attr) static bool valid_markcond(const struct inet_diag_bc_op *op, int len,
int *min_len)
{ {
*min_len += sizeof(struct inet_diag_markcond);
return len >= *min_len;
}
static int inet_diag_bc_audit(const struct nlattr *attr,
const struct sk_buff *skb)
{
bool net_admin = netlink_net_capable(skb, CAP_NET_ADMIN);
const void *bytecode, *bc; const void *bytecode, *bc;
int bytecode_len, len; int bytecode_len, len;
@ -738,6 +762,12 @@ static int inet_diag_bc_audit(const struct nlattr *attr)
if (!valid_port_comparison(bc, len, &min_len)) if (!valid_port_comparison(bc, len, &min_len))
return -EINVAL; return -EINVAL;
break; break;
case INET_DIAG_BC_MARK_COND:
if (!net_admin)
return -EPERM;
if (!valid_markcond(bc, len, &min_len))
return -EINVAL;
break;
case INET_DIAG_BC_AUTO: case INET_DIAG_BC_AUTO:
case INET_DIAG_BC_JMP: case INET_DIAG_BC_JMP:
case INET_DIAG_BC_NOP: case INET_DIAG_BC_NOP:
@ -1030,7 +1060,7 @@ static int inet_diag_rcv_msg_compat(struct sk_buff *skb, struct nlmsghdr *nlh)
attr = nlmsg_find_attr(nlh, hdrlen, attr = nlmsg_find_attr(nlh, hdrlen,
INET_DIAG_REQ_BYTECODE); INET_DIAG_REQ_BYTECODE);
err = inet_diag_bc_audit(attr); err = inet_diag_bc_audit(attr, skb);
if (err) if (err)
return err; return err;
} }
@ -1061,7 +1091,7 @@ static int inet_diag_handler_cmd(struct sk_buff *skb, struct nlmsghdr *h)
attr = nlmsg_find_attr(h, hdrlen, attr = nlmsg_find_attr(h, hdrlen,
INET_DIAG_REQ_BYTECODE); INET_DIAG_REQ_BYTECODE);
err = inet_diag_bc_audit(attr); err = inet_diag_bc_audit(attr, skb);
if (err) if (err)
return err; return err;
} }