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Subject[PATCH net-next 04/19] get rid of compat_mc_getsockopt()
Date
From: Al Viro <viro@zeniv.linux.org.uk>

now we can do MCAST_MSFILTER in compat ->getsockopt() without
playing silly buggers with copying things back and forth.
We can form a native struct group_filter (sans the variable-length
tail) on stack, pass that + pointer to the tail of original request
to the helper doing the bulk of the work, then do the rest of
copyout - same as the native getsockopt() does.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
include/net/compat.h | 3 --
net/compat.c | 79 ------------------------------------------------
net/ipv4/ip_sockglue.c | 44 +++++++++++++++++++++++++--
net/ipv6/ipv6_sockglue.c | 41 +++++++++++++++++++++++--
4 files changed, 79 insertions(+), 88 deletions(-)

diff --git a/include/net/compat.h b/include/net/compat.h
index 69a8cd29c0ae..d714076d63d5 100644
--- a/include/net/compat.h
+++ b/include/net/compat.h
@@ -70,9 +70,6 @@ int cmsghdr_from_user_compat_to_kern(struct msghdr *, struct sock *,
int compat_mc_setsockopt(struct sock *, int, int, char __user *, unsigned int,
int (*)(struct sock *, int, int, char __user *,
unsigned int));
-int compat_mc_getsockopt(struct sock *, int, int, char __user *, int __user *,
- int (*)(struct sock *, int, int, char __user *,
- int __user *));

struct compat_group_req {
__u32 gr_interface;
diff --git a/net/compat.c b/net/compat.c
index 032114de4fec..7bdfda2b382a 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -538,85 +538,6 @@ int compat_mc_setsockopt(struct sock *sock, int level, int optname,
}
EXPORT_SYMBOL(compat_mc_setsockopt);

-int compat_mc_getsockopt(struct sock *sock, int level, int optname,
- char __user *optval, int __user *optlen,
- int (*getsockopt)(struct sock *, int, int, char __user *, int __user *))
-{
- struct compat_group_filter __user *gf32 = (void __user *)optval;
- struct group_filter __user *kgf;
- int __user *koptlen;
- u32 interface, fmode, numsrc;
- int klen, ulen, err;
-
- if (optname != MCAST_MSFILTER)
- return getsockopt(sock, level, optname, optval, optlen);
-
- koptlen = compat_alloc_user_space(sizeof(*koptlen));
- if (!access_ok(optlen, sizeof(*optlen)) ||
- __get_user(ulen, optlen))
- return -EFAULT;
-
- /* adjust len for pad */
- klen = ulen + sizeof(*kgf) - sizeof(*gf32);
-
- if (klen < GROUP_FILTER_SIZE(0))
- return -EINVAL;
-
- if (!access_ok(koptlen, sizeof(*koptlen)) ||
- __put_user(klen, koptlen))
- return -EFAULT;
-
- /* have to allow space for previous compat_alloc_user_space, too */
- kgf = compat_alloc_user_space(klen+sizeof(*optlen));
-
- if (!access_ok(gf32, __COMPAT_GF0_SIZE) ||
- __get_user(interface, &gf32->gf_interface) ||
- __get_user(fmode, &gf32->gf_fmode) ||
- __get_user(numsrc, &gf32->gf_numsrc) ||
- __put_user(interface, &kgf->gf_interface) ||
- __put_user(fmode, &kgf->gf_fmode) ||
- __put_user(numsrc, &kgf->gf_numsrc) ||
- copy_in_user(&kgf->gf_group, &gf32->gf_group, sizeof(kgf->gf_group)))
- return -EFAULT;
-
- err = getsockopt(sock, level, optname, (char __user *)kgf, koptlen);
- if (err)
- return err;
-
- if (!access_ok(koptlen, sizeof(*koptlen)) ||
- __get_user(klen, koptlen))
- return -EFAULT;
-
- ulen = klen - (sizeof(*kgf)-sizeof(*gf32));
-
- if (!access_ok(optlen, sizeof(*optlen)) ||
- __put_user(ulen, optlen))
- return -EFAULT;
-
- if (!access_ok(kgf, klen) ||
- !access_ok(gf32, ulen) ||
- __get_user(interface, &kgf->gf_interface) ||
- __get_user(fmode, &kgf->gf_fmode) ||
- __get_user(numsrc, &kgf->gf_numsrc) ||
- __put_user(interface, &gf32->gf_interface) ||
- __put_user(fmode, &gf32->gf_fmode) ||
- __put_user(numsrc, &gf32->gf_numsrc))
- return -EFAULT;
- if (numsrc) {
- int copylen;
-
- klen -= GROUP_FILTER_SIZE(0);
- copylen = numsrc * sizeof(gf32->gf_slist[0]);
- if (copylen > klen)
- copylen = klen;
- if (copy_in_user(gf32->gf_slist, kgf->gf_slist, copylen))
- return -EFAULT;
- }
- return err;
-}
-EXPORT_SYMBOL(compat_mc_getsockopt);
-
-
/* Argument list sizes for compat_sys_socketcall */
#define AL(x) ((x) * sizeof(u32))
static unsigned char nas[21] = {
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index e3703a3e7ef4..65a30e7672ff 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1607,9 +1607,47 @@ int compat_ip_getsockopt(struct sock *sk, int level, int optname,
{
int err;

- if (optname == MCAST_MSFILTER)
- return compat_mc_getsockopt(sk, level, optname, optval, optlen,
- ip_getsockopt);
+ if (optname == MCAST_MSFILTER) {
+ const int size0 = offsetof(struct compat_group_filter, gf_slist);
+ struct compat_group_filter __user *p = (void __user *)optval;
+ struct compat_group_filter gf32;
+ struct group_filter gf;
+ int ulen, err;
+ int num;
+
+ if (level != SOL_IP)
+ return -EOPNOTSUPP;
+
+ if (get_user(ulen, optlen))
+ return -EFAULT;
+
+ if (ulen < size0)
+ return -EINVAL;
+
+ if (copy_from_user(&gf32, p, size0))
+ return -EFAULT;
+
+ gf.gf_interface = gf32.gf_interface;
+ gf.gf_fmode = gf32.gf_fmode;
+ num = gf.gf_numsrc = gf32.gf_numsrc;
+ gf.gf_group = gf32.gf_group;
+
+ rtnl_lock();
+ lock_sock(sk);
+ err = ip_mc_gsfget(sk, &gf, p->gf_slist);
+ release_sock(sk);
+ rtnl_unlock();
+ if (err)
+ return err;
+ if (gf.gf_numsrc < num)
+ num = gf.gf_numsrc;
+ ulen = GROUP_FILTER_SIZE(num) - (sizeof(gf) - sizeof(gf32));
+ if (put_user(ulen, optlen) ||
+ put_user(gf.gf_fmode, &p->gf_fmode) ||
+ put_user(gf.gf_numsrc, &p->gf_numsrc))
+ return -EFAULT;
+ return 0;
+ }

err = do_ip_getsockopt(sk, level, optname, optval, optlen,
MSG_CMSG_COMPAT);
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index e4a62ca1a3d0..0bbafe73bdde 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -1446,9 +1446,44 @@ int compat_ipv6_getsockopt(struct sock *sk, int level, int optname,
if (level != SOL_IPV6)
return -ENOPROTOOPT;

- if (optname == MCAST_MSFILTER)
- return compat_mc_getsockopt(sk, level, optname, optval, optlen,
- ipv6_getsockopt);
+ if (optname == MCAST_MSFILTER) {
+ const int size0 = offsetof(struct compat_group_filter, gf_slist);
+ struct compat_group_filter __user *p = (void __user *)optval;
+ struct compat_group_filter gf32;
+ struct group_filter gf;
+ int ulen, err;
+ int num;
+
+ if (get_user(ulen, optlen))
+ return -EFAULT;
+
+ if (ulen < size0)
+ return -EINVAL;
+
+ if (copy_from_user(&gf32, p, size0))
+ return -EFAULT;
+
+ gf.gf_interface = gf32.gf_interface;
+ gf.gf_fmode = gf32.gf_fmode;
+ num = gf.gf_numsrc = gf32.gf_numsrc;
+ gf.gf_group = gf32.gf_group;
+
+ if (gf.gf_group.ss_family != AF_INET6)
+ return -EADDRNOTAVAIL;
+ lock_sock(sk);
+ err = ip6_mc_msfget(sk, &gf, p->gf_slist);
+ release_sock(sk);
+ if (err)
+ return err;
+ if (num > gf.gf_numsrc)
+ num = gf.gf_numsrc;
+ ulen = GROUP_FILTER_SIZE(num) - (sizeof(gf)-sizeof(gf32));
+ if (put_user(ulen, optlen) ||
+ put_user(gf.gf_fmode, &p->gf_fmode) ||
+ put_user(gf.gf_numsrc, &p->gf_numsrc))
+ return -EFAULT;
+ return 0;
+ }

err = do_ipv6_getsockopt(sk, level, optname, optval, optlen,
MSG_CMSG_COMPAT);
--
2.11.0
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