[PATCH net-next 03/19] ip*_mc_gsfget(): lift copyout of struct group_filter into callers

From: Al Viro
Date: Wed May 20 2020 - 20:38:57 EST


From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

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 <viro@xxxxxxxxxxxxxxxxxx>
---
include/linux/igmp.h | 2 +-
include/net/ipv6.h | 2 +-
net/ipv4/igmp.c | 18 +++++-------------
net/ipv4/ip_sockglue.c | 19 ++++++++++++++-----
net/ipv6/ipv6_sockglue.c | 18 ++++++++++++++----
net/ipv6/mcast.c | 10 +++-------
6 files changed, 38 insertions(+), 31 deletions(-)

diff --git a/include/linux/igmp.h b/include/linux/igmp.h
index faa6586a5783..64ce8cd1cfaf 100644
--- a/include/linux/igmp.h
+++ b/include/linux/igmp.h
@@ -123,7 +123,7 @@ extern int ip_mc_msfilter(struct sock *sk, struct ip_msfilter *msf,int ifindex);
extern int ip_mc_msfget(struct sock *sk, struct ip_msfilter *msf,
struct ip_msfilter __user *optval, int __user *optlen);
extern int ip_mc_gsfget(struct sock *sk, struct group_filter *gsf,
- struct group_filter __user *optval, int __user *optlen);
+ struct sockaddr_storage __user *p);
extern int ip_mc_sf_allow(struct sock *sk, __be32 local, __be32 rmt,
int dif, int sdif);
extern void ip_mc_init_dev(struct in_device *);
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 5fc3a9d7b053..c45eb78d970f 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -1138,7 +1138,7 @@ int ip6_mc_source(int add, int omode, struct sock *sk,
struct group_source_req *pgsr);
int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf);
int ip6_mc_msfget(struct sock *sk, struct group_filter *gsf,
- struct group_filter __user *optval, int __user *optlen);
+ struct sockaddr_storage __user *p);

#ifdef CONFIG_PROC_FS
int ac6_proc_init(struct net *net);
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index 47f0502b2101..7b272bbed2b4 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -2565,9 +2565,9 @@ int ip_mc_msfget(struct sock *sk, struct ip_msfilter *msf,
}

int ip_mc_gsfget(struct sock *sk, struct group_filter *gsf,
- struct group_filter __user *optval, int __user *optlen)
+ struct sockaddr_storage __user *p)
{
- int err, i, count, copycount;
+ int i, count, copycount;
struct sockaddr_in *psin;
__be32 addr;
struct ip_mc_socklist *pmc;
@@ -2583,37 +2583,29 @@ int ip_mc_gsfget(struct sock *sk, struct group_filter *gsf,
if (!ipv4_is_multicast(addr))
return -EINVAL;

- err = -EADDRNOTAVAIL;
-
for_each_pmc_rtnl(inet, pmc) {
if (pmc->multi.imr_multiaddr.s_addr == addr &&
pmc->multi.imr_ifindex == gsf->gf_interface)
break;
}
if (!pmc) /* must have a prior join */
- goto done;
+ return -EADDRNOTAVAIL;
gsf->gf_fmode = pmc->sfmode;
psl = rtnl_dereference(pmc->sflist);
count = psl ? psl->sl_count : 0;
copycount = count < gsf->gf_numsrc ? count : gsf->gf_numsrc;
gsf->gf_numsrc = count;
- if (put_user(GROUP_FILTER_SIZE(copycount), optlen) ||
- copy_to_user(optval, gsf, GROUP_FILTER_SIZE(0))) {
- return -EFAULT;
- }
- for (i = 0; i < copycount; i++) {
+ for (i = 0; i < copycount; i++, p++) {
struct sockaddr_storage ss;

psin = (struct sockaddr_in *)&ss;
memset(&ss, 0, sizeof(ss));
psin->sin_family = AF_INET;
psin->sin_addr.s_addr = psl->sl_addr[i];
- if (copy_to_user(&optval->gf_slist[i], &ss, sizeof(ss)))
+ if (copy_to_user(p, &ss, sizeof(ss)))
return -EFAULT;
}
return 0;
-done:
- return err;
}

/*
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:
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 96e3f603c8d8..e4a62ca1a3d0 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -1056,18 +1056,28 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
break;
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;
int err;

- if (len < GROUP_FILTER_SIZE(0))
+ if (len < size0)
return -EINVAL;
- if (copy_from_user(&gsf, optval, GROUP_FILTER_SIZE(0)))
+ if (copy_from_user(&gsf, p, size0))
return -EFAULT;
if (gsf.gf_group.ss_family != AF_INET6)
return -EADDRNOTAVAIL;
+ num = gsf.gf_numsrc;
lock_sock(sk);
- err = ip6_mc_msfget(sk, &gsf,
- (struct group_filter __user *)optval, optlen);
+ err = ip6_mc_msfget(sk, &gsf, p->gf_slist);
+ if (!err) {
+ if (num > gsf.gf_numsrc)
+ num = gsf.gf_numsrc;
+ if (put_user(GROUP_FILTER_SIZE(num), optlen) ||
+ copy_to_user(p, &gsf, size0))
+ err = -EFAULT;
+ }
release_sock(sk);
return err;
}
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index eaa4c2cc2fbb..97d796c7d6c0 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -547,7 +547,7 @@ int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf)
}

int ip6_mc_msfget(struct sock *sk, struct group_filter *gsf,
- struct group_filter __user *optval, int __user *optlen)
+ struct sockaddr_storage *p)
{
int err, i, count, copycount;
const struct in6_addr *group;
@@ -592,14 +592,10 @@ int ip6_mc_msfget(struct sock *sk, struct group_filter *gsf,

copycount = count < gsf->gf_numsrc ? count : gsf->gf_numsrc;
gsf->gf_numsrc = count;
- if (put_user(GROUP_FILTER_SIZE(copycount), optlen) ||
- copy_to_user(optval, gsf, GROUP_FILTER_SIZE(0))) {
- return -EFAULT;
- }
/* changes to psl require the socket lock, and a write lock
* on pmc->sflock. We have the socket lock so reading here is safe.
*/
- for (i = 0; i < copycount; i++) {
+ for (i = 0; i < copycount; i++, p++) {
struct sockaddr_in6 *psin6;
struct sockaddr_storage ss;

@@ -607,7 +603,7 @@ int ip6_mc_msfget(struct sock *sk, struct group_filter *gsf,
memset(&ss, 0, sizeof(ss));
psin6->sin6_family = AF_INET6;
psin6->sin6_addr = psl->sl_addr[i];
- if (copy_to_user(&optval->gf_slist[i], &ss, sizeof(ss)))
+ if (copy_to_user(p, &ss, sizeof(ss)))
return -EFAULT;
}
return 0;
--
2.11.0