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igmp: Fix data-races around sysctl_igmp_max_msf.

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While reading sysctl_igmp_max_msf, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Kuniyuki Iwashima 2022-07-15 10:17:43 -07:00 committed by David S. Miller
parent 6305d821e3
commit 6ae0f2e553
2 changed files with 4 additions and 4 deletions
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2
net/ipv4/igmp.c
View File

@ -2384,7 +2384,7 @@ int ip_mc_source(int add, int omode, struct sock *sk, struct
}
/* else, add a new source to the filter */
if (psl && psl->sl_count >= net->ipv4.sysctl_igmp_max_msf) {
if (psl && psl->sl_count >= READ_ONCE(net->ipv4.sysctl_igmp_max_msf)) {
err = -ENOBUFS;
goto done;
}

6
net/ipv4/ip_sockglue.c
View File

@ -782,7 +782,7 @@ static int ip_set_mcast_msfilter(struct sock *sk, sockptr_t optval, int optlen)
/* numsrc >= (4G-140)/128 overflow in 32 bits */
err = -ENOBUFS;
if (gsf->gf_numsrc >= 0x1ffffff ||
gsf->gf_numsrc > sock_net(sk)->ipv4.sysctl_igmp_max_msf)
gsf->gf_numsrc > READ_ONCE(sock_net(sk)->ipv4.sysctl_igmp_max_msf))
goto out_free_gsf;
err = -EINVAL;
@ -832,7 +832,7 @@ static int compat_ip_set_mcast_msfilter(struct sock *sk, sockptr_t optval,
/* numsrc >= (4G-140)/128 overflow in 32 bits */
err = -ENOBUFS;
if (n > sock_net(sk)->ipv4.sysctl_igmp_max_msf)
if (n > READ_ONCE(sock_net(sk)->ipv4.sysctl_igmp_max_msf))
goto out_free_gsf;
err = set_mcast_msfilter(sk, gf32->gf_interface, n, gf32->gf_fmode,
&gf32->gf_group, gf32->gf_slist_flex);
@ -1244,7 +1244,7 @@ static int do_ip_setsockopt(struct sock *sk, int level, int optname,
}
/* numsrc >= (1G-4) overflow in 32 bits */
if (msf->imsf_numsrc >= 0x3ffffffcU ||
msf->imsf_numsrc > net->ipv4.sysctl_igmp_max_msf) {
msf->imsf_numsrc > READ_ONCE(net->ipv4.sysctl_igmp_max_msf)) {
kfree(msf);
err = -ENOBUFS;
break;