net: Several cleanups for the setsockopt compat support.

1) added missing "__user" for kgsr and kgf pointers
2) verify read for only GROUP_FILTER_SIZE(0). The group_filter
        structure definition (via RFC) includes space for one source
        in the source list array, but that source need not be present.
        So, sizeof(group_filter) > GROUP_FILTER_SIZE(0). Fixed
        the user read-check for minimum length to use the smaller size.
3) remove unneeded "&" for gf_slist addresses

Signed-off-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 4 deletions

diff --git a/net/compat.c b/net/compat.c
index 01bf95d0832..8146f654391 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -548,6 +548,9 @@ struct compat_group_filter {
                 __attribute__ ((aligned(4)));
 } __attribute__ ((packed));
 
+#define __COMPAT_GF0_SIZE (sizeof(struct compat_group_filter) - \
+                        sizeof(struct __kernel_sockaddr_storage))
+
 
 int compat_mc_setsockopt(struct sock *sock, int level, int optname,
         char __user *optval, int optlen,
@@ -582,7 +585,7 @@ int compat_mc_setsockopt(struct sock *sock, int level, int optname,
         case MCAST_UNBLOCK_SOURCE:
         {
                 struct compat_group_source_req __user *gsr32 = (void *)optval;
-                struct group_source_req *kgsr = compat_alloc_user_space(
+                struct group_source_req __user *kgsr = compat_alloc_user_space(
                         sizeof(struct group_source_req));
                 u32 interface;
 
@@ -603,10 +606,10 @@ int compat_mc_setsockopt(struct sock *sock, int level, int optname,
         case MCAST_MSFILTER:
         {
                 struct compat_group_filter __user *gf32 = (void *)optval;
-                struct group_filter *kgf;
+                struct group_filter __user *kgf;
                 u32 interface, fmode, numsrc;
 
-                if (!access_ok(VERIFY_READ, gf32, sizeof(*gf32)) ||
+                if (!access_ok(VERIFY_READ, gf32, __COMPAT_GF0_SIZE) ||
                     __get_user(interface, &gf32->gf_interface) ||
                     __get_user(fmode, &gf32->gf_fmode) ||
                     __get_user(numsrc, &gf32->gf_numsrc))
@@ -622,7 +625,7 @@ int compat_mc_setsockopt(struct sock *sock, int level, int optname,
                     __put_user(numsrc, &kgf->gf_numsrc) ||
                     copy_in_user(&kgf->gf_group, &gf32->gf_group,
                                 sizeof(kgf->gf_group)) ||
-                    (numsrc && copy_in_user(&kgf->gf_slist, &gf32->gf_slist,
+                    (numsrc && copy_in_user(kgf->gf_slist, gf32->gf_slist,
                                 numsrc * sizeof(kgf->gf_slist[0]))))
                         return -EFAULT;
                 koptval = (char __user *)kgf;