From e11c0e258c1a87e478a7a44e7c3d9e8ea4b8438c Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Wed, 4 Aug 2021 16:43:52 -0500 Subject: [PATCH] net/ipv6/mcast: Use struct_size() helper 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 Signed-off-by: David S. Miller --- include/net/if_inet6.h | 3 --- net/ipv6/mcast.c | 20 +++++++++++++------- 2 files changed, 13 insertions(+), 10 deletions(-) diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h index 71bb4cc..42235c1 100644 --- a/include/net/if_inet6.h +++ b/include/net/if_inet6.h @@ -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 { diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index 54ec163..cd951fa 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -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); } -- 2.7.4