[PATCH 14/22] net/ipv4: factor out MCAST_MSFILTER getsockopt helpers

From: Christoph Hellwig
Date: Fri Jul 17 2020 - 02:26:06 EST


Factor out one helper each for getting the native and compat
version of the MCAST_MSFILTER option.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
net/ipv4/ip_sockglue.c | 131 ++++++++++++++++++++++-------------------
1 file changed, 70 insertions(+), 61 deletions(-)

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 95f4248c6fc5ed..70d32c9476a2e3 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1468,6 +1468,74 @@ static bool getsockopt_needs_rtnl(int optname)
return false;
}

+static int ip_get_mcast_msfilter(struct sock *sk, void __user *optval,
+ int __user *optlen, int len)
+{
+ const int size0 = offsetof(struct group_filter, gf_slist);
+ struct group_filter __user *p = optval;
+ struct group_filter gsf;
+ int num;
+ int err;
+
+ if (len < size0)
+ return -EINVAL;
+ if (copy_from_user(&gsf, p, size0))
+ return -EFAULT;
+
+ num = gsf.gf_numsrc;
+ err = ip_mc_gsfget(sk, &gsf, p->gf_slist);
+ if (err)
+ return err;
+ if (gsf.gf_numsrc < num)
+ num = gsf.gf_numsrc;
+ if (put_user(GROUP_FILTER_SIZE(num), optlen) ||
+ copy_to_user(p, &gsf, size0))
+ return -EFAULT;
+ return 0;
+}
+
+#ifdef CONFIG_COMPAT
+static int compat_ip_get_mcast_msfilter(struct sock *sk, void __user *optval,
+ int __user *optlen)
+{
+ const int size0 = offsetof(struct compat_group_filter, gf_slist);
+ struct compat_group_filter __user *p = optval;
+ struct compat_group_filter gf32;
+ struct group_filter gf;
+ int len, err;
+ int num;
+
+ if (get_user(len, optlen))
+ return -EFAULT;
+ if (len < 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;
+ len = GROUP_FILTER_SIZE(num) - (sizeof(gf) - sizeof(gf32));
+ if (put_user(len, optlen) ||
+ put_user(gf.gf_fmode, &p->gf_fmode) ||
+ put_user(gf.gf_numsrc, &p->gf_numsrc))
+ return -EFAULT;
+ return 0;
+}
+#endif
+
static int do_ip_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *optlen, unsigned int flags)
{
@@ -1626,31 +1694,8 @@ static int do_ip_getsockopt(struct sock *sk, int level, int optname,
goto out;
}
case MCAST_MSFILTER:
- {
- struct group_filter __user *p = (void __user *)optval;
- struct group_filter gsf;
- const int size0 = offsetof(struct group_filter, gf_slist);
- int num;
-
- if (len < size0) {
- err = -EINVAL;
- goto out;
- }
- if (copy_from_user(&gsf, p, size0)) {
- err = -EFAULT;
- goto out;
- }
- num = gsf.gf_numsrc;
- err = ip_mc_gsfget(sk, &gsf, p->gf_slist);
- if (err)
- goto out;
- if (gsf.gf_numsrc < num)
- num = gsf.gf_numsrc;
- if (put_user(GROUP_FILTER_SIZE(num), optlen) ||
- copy_to_user(p, &gsf, size0))
- err = -EFAULT;
+ err = ip_get_mcast_msfilter(sk, optval, optlen, len);
goto out;
- }
case IP_MULTICAST_ALL:
val = inet->mc_all;
break;
@@ -1762,45 +1807,9 @@ int compat_ip_getsockopt(struct sock *sk, int level, int optname,
int err;

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;
+ return compat_ip_get_mcast_msfilter(sk, optval, optlen);
}

err = do_ip_getsockopt(sk, level, optname, optval, optlen,
--
2.27.0