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net/ipv6/mcast: Use struct_size() helper

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Replace IP6_SFLSIZE() with struct_size() helper in order to avoid any
potential type mistakes or integer overflows that, in the worst
scenario, could lead to heap overflows.

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Gustavo A. R. Silva 2021-08-04 16:43:52 -05:00 committed by David S. Miller
parent e6a1f7e0b0
commit e11c0e258c
2 changed files with 13 additions and 10 deletions
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3
include/net/if_inet6.h
View File

@ -82,9 +82,6 @@ struct ip6_sf_socklist {
struct in6_addr sl_addr[];
};
#define IP6_SFLSIZE(count) (sizeof(struct ip6_sf_socklist) + \
(count) * sizeof(struct in6_addr))
#define IP6_SFBLOCK 10 /* allocate this many at once */
struct ipv6_mc_socklist {

20
net/ipv6/mcast.c
View File

@ -447,7 +447,8 @@ int ip6_mc_source(int add, int omode, struct sock *sk,
if (psl)
count += psl->sl_max;
newpsl = sock_kmalloc(sk, IP6_SFLSIZE(count), GFP_KERNEL);
newpsl = sock_kmalloc(sk, struct_size(newpsl, sl_addr, count),
GFP_KERNEL);
if (!newpsl) {
err = -ENOBUFS;
goto done;
@ -457,7 +458,8 @@ int ip6_mc_source(int add, int omode, struct sock *sk,
if (psl) {
for (i = 0; i < psl->sl_count; i++)
newpsl->sl_addr[i] = psl->sl_addr[i];
atomic_sub(IP6_SFLSIZE(psl->sl_max), &sk->sk_omem_alloc);
atomic_sub(struct_size(psl, sl_addr, psl->sl_max),
&sk->sk_omem_alloc);
kfree_rcu(psl, rcu);
}
psl = newpsl;
@ -525,8 +527,9 @@ int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf,
goto done;
}
if (gsf->gf_numsrc) {
newpsl = sock_kmalloc(sk, IP6_SFLSIZE(gsf->gf_numsrc),
GFP_KERNEL);
newpsl = sock_kmalloc(sk, struct_size(newpsl, sl_addr,
gsf->gf_numsrc),
GFP_KERNEL);
if (!newpsl) {
err = -ENOBUFS;
goto done;
@ -543,7 +546,8 @@ int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf,
newpsl->sl_count, newpsl->sl_addr, 0);
if (err) {
mutex_unlock(&idev->mc_lock);
sock_kfree_s(sk, newpsl, IP6_SFLSIZE(newpsl->sl_max));
sock_kfree_s(sk, newpsl, struct_size(newpsl, sl_addr,
newpsl->sl_max));
goto done;
}
mutex_unlock(&idev->mc_lock);
@ -559,7 +563,8 @@ int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf,
if (psl) {
ip6_mc_del_src(idev, group, pmc->sfmode,
psl->sl_count, psl->sl_addr, 0);
atomic_sub(IP6_SFLSIZE(psl->sl_max), &sk->sk_omem_alloc);
atomic_sub(struct_size(psl, sl_addr, psl->sl_max),
&sk->sk_omem_alloc);
kfree_rcu(psl, rcu);
} else {
ip6_mc_del_src(idev, group, pmc->sfmode, 0, NULL, 0);
@ -2607,7 +2612,8 @@ static int ip6_mc_leave_src(struct sock *sk, struct ipv6_mc_socklist *iml,
err = ip6_mc_del_src(idev, &iml->addr, iml->sfmode,
psl->sl_count, psl->sl_addr, 0);
RCU_INIT_POINTER(iml->sflist, NULL);
atomic_sub(IP6_SFLSIZE(psl->sl_max), &sk->sk_omem_alloc);
atomic_sub(struct_size(psl, sl_addr, psl->sl_max),
&sk->sk_omem_alloc);
kfree_rcu(psl, rcu);
}