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e1d001fa5b
Most of the ioctls to net protocols operates directly on userspace
argument (arg). Usually doing get_user()/put_user() directly in the
ioctl callback. This is not flexible, because it is hard to reuse these
functions without passing userspace buffers.
Change the "struct proto" ioctls to avoid touching userspace memory and
operate on kernel buffers, i.e., all protocol's ioctl callbacks is
adapted to operate on a kernel memory other than on userspace (so, no
more {put,get}_user() and friends being called in the ioctl callback).
This changes the "struct proto" ioctl format in the following way:
int (*ioctl)(struct sock *sk, int cmd,
- unsigned long arg);
+ int *karg);
(Important to say that this patch does not touch the "struct proto_ops"
protocols)
So, the "karg" argument, which is passed to the ioctl callback, is a
pointer allocated to kernel space memory (inside a function wrapper).
This buffer (karg) may contain input argument (copied from userspace in
a prep function) and it might return a value/buffer, which is copied
back to userspace if necessary. There is not one-size-fits-all format
(that is I am using 'may' above), but basically, there are three type of
ioctls:
1) Do not read from userspace, returns a result to userspace
2) Read an input parameter from userspace, and does not return anything
to userspace
3) Read an input from userspace, and return a buffer to userspace.
The default case (1) (where no input parameter is given, and an "int" is
returned to userspace) encompasses more than 90% of the cases, but there
are two other exceptions. Here is a list of exceptions:
* Protocol RAW:
* cmd = SIOCGETVIFCNT:
* input and output = struct sioc_vif_req
* cmd = SIOCGETSGCNT
* input and output = struct sioc_sg_req
* Explanation: for the SIOCGETVIFCNT case, userspace passes the input
argument, which is struct sioc_vif_req. Then the callback populates
the struct, which is copied back to userspace.
* Protocol RAW6:
* cmd = SIOCGETMIFCNT_IN6
* input and output = struct sioc_mif_req6
* cmd = SIOCGETSGCNT_IN6
* input and output = struct sioc_sg_req6
* Protocol PHONET:
* cmd == SIOCPNADDRESOURCE | SIOCPNDELRESOURCE
* input int (4 bytes)
* Nothing is copied back to userspace.
For the exception cases, functions sock_sk_ioctl_inout() will
copy the userspace input, and copy it back to kernel space.
The wrapper that prepare the buffer and put the buffer back to user is
sk_ioctl(), so, instead of calling sk->sk_prot->ioctl(), the callee now
calls sk_ioctl(), which will handle all cases.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230609152800.830401-1-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
106 lines
2.3 KiB
C
106 lines
2.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_MROUTE_H
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#define __LINUX_MROUTE_H
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#include <linux/in.h>
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#include <linux/pim.h>
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#include <net/fib_rules.h>
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#include <net/fib_notifier.h>
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#include <uapi/linux/mroute.h>
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#include <linux/mroute_base.h>
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#include <linux/sockptr.h>
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#ifdef CONFIG_IP_MROUTE
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static inline int ip_mroute_opt(int opt)
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{
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return opt >= MRT_BASE && opt <= MRT_MAX;
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}
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static inline int sk_is_ipmr(struct sock *sk)
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{
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return sk->sk_family == AF_INET &&
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inet_sk(sk)->inet_num == IPPROTO_IGMP;
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}
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int ip_mroute_setsockopt(struct sock *, int, sockptr_t, unsigned int);
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int ip_mroute_getsockopt(struct sock *, int, sockptr_t, sockptr_t);
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int ipmr_ioctl(struct sock *sk, int cmd, void *arg);
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int ipmr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg);
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int ip_mr_init(void);
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bool ipmr_rule_default(const struct fib_rule *rule);
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int ipmr_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg);
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#else
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static inline int ip_mroute_setsockopt(struct sock *sock, int optname,
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sockptr_t optval, unsigned int optlen)
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{
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return -ENOPROTOOPT;
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}
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static inline int ip_mroute_getsockopt(struct sock *sk, int optname,
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sockptr_t optval, sockptr_t optlen)
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{
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return -ENOPROTOOPT;
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}
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static inline int ipmr_ioctl(struct sock *sk, int cmd, void *arg)
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{
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return -ENOIOCTLCMD;
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}
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static inline int ip_mr_init(void)
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{
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return 0;
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}
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static inline int ip_mroute_opt(int opt)
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{
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return 0;
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}
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static inline int sk_is_ipmr(struct sock *sk)
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{
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return 0;
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}
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static inline bool ipmr_rule_default(const struct fib_rule *rule)
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{
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return true;
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}
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static inline int ipmr_sk_ioctl(struct sock *sk, unsigned int cmd,
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void __user *arg)
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{
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return 1;
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}
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#endif
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#define VIFF_STATIC 0x8000
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struct mfc_cache_cmp_arg {
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__be32 mfc_mcastgrp;
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__be32 mfc_origin;
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};
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/**
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* struct mfc_cache - multicast routing entries
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* @_c: Common multicast routing information; has to be first [for casting]
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* @mfc_mcastgrp: destination multicast group address
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* @mfc_origin: source address
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* @cmparg: used for rhashtable comparisons
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*/
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struct mfc_cache {
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struct mr_mfc _c;
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union {
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struct {
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__be32 mfc_mcastgrp;
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__be32 mfc_origin;
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};
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struct mfc_cache_cmp_arg cmparg;
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};
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};
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struct rtmsg;
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int ipmr_get_route(struct net *net, struct sk_buff *skb,
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__be32 saddr, __be32 daddr,
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struct rtmsg *rtm, u32 portid);
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#endif
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