From 931ca7ab7fe804d77bc6952f1512950c0d870f26 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 29 Mar 2020 17:18:30 -0400 Subject: ip*_mc_gsfget(): lift copyout of struct group_filter into callers pass the userland pointer to the array in its tail, so that part gets copied out by our functions; copyout of everything else is done in the callers. Rationale: reuse for compat; the array is the same in native and compat, the layout of parts before it is different for compat. Signed-off-by: Al Viro --- net/ipv4/ip_sockglue.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) (limited to 'net/ipv4/ip_sockglue.c') diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index 3c2c6cd3933b..e3703a3e7ef4 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -1473,19 +1473,28 @@ static int do_ip_getsockopt(struct sock *sk, int level, int optname, } 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 < GROUP_FILTER_SIZE(0)) { + if (len < size0) { err = -EINVAL; goto out; } - if (copy_from_user(&gsf, optval, GROUP_FILTER_SIZE(0))) { + if (copy_from_user(&gsf, p, size0)) { err = -EFAULT; goto out; } - err = ip_mc_gsfget(sk, &gsf, - (struct group_filter __user *)optval, - optlen); + 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; goto out; } case IP_MULTICAST_ALL: -- cgit v1.2.3