From e6a1f7e0b0fe5997b896b793c70d12fc5ed06cdd Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Wed, 4 Aug 2021 16:18:50 -0500 Subject: [PATCH] net/ipv4/igmp: Use struct_size() helper Replace IP_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/linux/igmp.h | 3 --- net/ipv4/igmp.c | 20 +++++++++++++------- 2 files changed, 13 insertions(+), 10 deletions(-) diff --git a/include/linux/igmp.h b/include/linux/igmp.h index 64ce8cd..93c262e 100644 --- a/include/linux/igmp.h +++ b/include/linux/igmp.h @@ -41,9 +41,6 @@ struct ip_sf_socklist { __be32 sl_addr[]; }; -#define IP_SFLSIZE(count) (sizeof(struct ip_sf_socklist) + \ - (count) * sizeof(__be32)) - #define IP_SFBLOCK 10 /* allocate this many at once */ /* ip_mc_socklist is real list now. Speed is not argument; diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c index c2d477e..7e50727 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -2233,7 +2233,7 @@ static int ip_mc_leave_src(struct sock *sk, struct ip_mc_socklist *iml, iml->sfmode, psf->sl_count, psf->sl_addr, 0); RCU_INIT_POINTER(iml->sflist, NULL); /* decrease mem now to avoid the memleak warning */ - atomic_sub(IP_SFLSIZE(psf->sl_max), &sk->sk_omem_alloc); + atomic_sub(struct_size(psf, sl_addr, psf->sl_max), &sk->sk_omem_alloc); kfree_rcu(psf, rcu); return err; } @@ -2382,7 +2382,8 @@ int ip_mc_source(int add, int omode, struct sock *sk, struct if (psl) count += psl->sl_max; - newpsl = sock_kmalloc(sk, IP_SFLSIZE(count), GFP_KERNEL); + newpsl = sock_kmalloc(sk, struct_size(newpsl, sl_addr, count), + GFP_KERNEL); if (!newpsl) { err = -ENOBUFS; goto done; @@ -2393,7 +2394,8 @@ int ip_mc_source(int add, int omode, struct sock *sk, struct for (i = 0; i < psl->sl_count; i++) newpsl->sl_addr[i] = psl->sl_addr[i]; /* decrease mem now to avoid the memleak warning */ - atomic_sub(IP_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); } rcu_assign_pointer(pmc->sflist, newpsl); @@ -2468,8 +2470,9 @@ int ip_mc_msfilter(struct sock *sk, struct ip_msfilter *msf, int ifindex) goto done; } if (msf->imsf_numsrc) { - newpsl = sock_kmalloc(sk, IP_SFLSIZE(msf->imsf_numsrc), - GFP_KERNEL); + newpsl = sock_kmalloc(sk, struct_size(newpsl, sl_addr, + msf->imsf_numsrc), + GFP_KERNEL); if (!newpsl) { err = -ENOBUFS; goto done; @@ -2480,7 +2483,9 @@ int ip_mc_msfilter(struct sock *sk, struct ip_msfilter *msf, int ifindex) err = ip_mc_add_src(in_dev, &msf->imsf_multiaddr, msf->imsf_fmode, newpsl->sl_count, newpsl->sl_addr, 0); if (err) { - sock_kfree_s(sk, newpsl, IP_SFLSIZE(newpsl->sl_max)); + sock_kfree_s(sk, newpsl, + struct_size(newpsl, sl_addr, + newpsl->sl_max)); goto done; } } else { @@ -2493,7 +2498,8 @@ int ip_mc_msfilter(struct sock *sk, struct ip_msfilter *msf, int ifindex) (void) ip_mc_del_src(in_dev, &msf->imsf_multiaddr, pmc->sfmode, psl->sl_count, psl->sl_addr, 0); /* decrease mem now to avoid the memleak warning */ - atomic_sub(IP_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 (void) ip_mc_del_src(in_dev, &msf->imsf_multiaddr, pmc->sfmode, -- 2.7.4