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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>
121 lines
3.0 KiB
C
121 lines
3.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_ICMPV6_H
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#define _LINUX_ICMPV6_H
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#include <linux/skbuff.h>
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#include <linux/ipv6.h>
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#include <uapi/linux/icmpv6.h>
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static inline struct icmp6hdr *icmp6_hdr(const struct sk_buff *skb)
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{
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return (struct icmp6hdr *)skb_transport_header(skb);
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}
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#include <linux/netdevice.h>
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#if IS_ENABLED(CONFIG_IPV6)
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typedef void ip6_icmp_send_t(struct sk_buff *skb, u8 type, u8 code, __u32 info,
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const struct in6_addr *force_saddr,
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const struct inet6_skb_parm *parm);
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void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
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const struct in6_addr *force_saddr,
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const struct inet6_skb_parm *parm);
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#if IS_BUILTIN(CONFIG_IPV6)
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static inline void __icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
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const struct inet6_skb_parm *parm)
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{
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icmp6_send(skb, type, code, info, NULL, parm);
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}
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static inline int inet6_register_icmp_sender(ip6_icmp_send_t *fn)
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{
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BUILD_BUG_ON(fn != icmp6_send);
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return 0;
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}
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static inline int inet6_unregister_icmp_sender(ip6_icmp_send_t *fn)
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{
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BUILD_BUG_ON(fn != icmp6_send);
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return 0;
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}
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#else
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extern void __icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
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const struct inet6_skb_parm *parm);
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extern int inet6_register_icmp_sender(ip6_icmp_send_t *fn);
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extern int inet6_unregister_icmp_sender(ip6_icmp_send_t *fn);
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#endif
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static inline void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
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{
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__icmpv6_send(skb, type, code, info, IP6CB(skb));
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}
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int ip6_err_gen_icmpv6_unreach(struct sk_buff *skb, int nhs, int type,
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unsigned int data_len);
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#if IS_ENABLED(CONFIG_NF_NAT)
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void icmpv6_ndo_send(struct sk_buff *skb_in, u8 type, u8 code, __u32 info);
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#else
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static inline void icmpv6_ndo_send(struct sk_buff *skb_in, u8 type, u8 code, __u32 info)
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{
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struct inet6_skb_parm parm = { 0 };
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__icmpv6_send(skb_in, type, code, info, &parm);
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}
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#endif
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#else
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static inline void icmpv6_send(struct sk_buff *skb,
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u8 type, u8 code, __u32 info)
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{
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}
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static inline void icmpv6_ndo_send(struct sk_buff *skb,
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u8 type, u8 code, __u32 info)
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{
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}
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#endif
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extern int icmpv6_init(void);
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extern int icmpv6_err_convert(u8 type, u8 code,
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int *err);
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extern void icmpv6_cleanup(void);
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extern void icmpv6_param_prob_reason(struct sk_buff *skb,
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u8 code, int pos,
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enum skb_drop_reason reason);
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struct flowi6;
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struct in6_addr;
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extern void icmpv6_flow_init(struct sock *sk,
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struct flowi6 *fl6,
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u8 type,
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const struct in6_addr *saddr,
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const struct in6_addr *daddr,
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int oif);
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static inline void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos)
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{
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icmpv6_param_prob_reason(skb, code, pos,
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SKB_DROP_REASON_NOT_SPECIFIED);
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}
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static inline bool icmpv6_is_err(int type)
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{
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switch (type) {
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case ICMPV6_DEST_UNREACH:
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case ICMPV6_PKT_TOOBIG:
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case ICMPV6_TIME_EXCEED:
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case ICMPV6_PARAMPROB:
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return true;
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}
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return false;
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}
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static inline int sk_is_icmpv6(struct sock *sk)
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{
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return sk->sk_family == AF_INET6 &&
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inet_sk(sk)->inet_num == IPPROTO_ICMPV6;
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}
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#endif
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