From: Kuniyuki Iwashima kuniyu@amazon.com
[ Upstream commit 9b55c20f83369dd54541d9ddbe3a018a8377f451 ]
sysctl_ip_prot_sock is accessed concurrently, and there is always a chance of data-race. So, all readers and writers need some basic protection to avoid load/store-tearing.
Fixes: 4548b683b781 ("Introduce a sysctl that modifies the value of PROT_SOCK.") Signed-off-by: Kuniyuki Iwashima kuniyu@amazon.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/ip.h | 2 +- net/ipv4/sysctl_net_ipv4.c | 6 +++--- 2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/net/ip.h b/include/net/ip.h index 4a15b6bcb4b8..1c979fd1904c 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -357,7 +357,7 @@ static inline bool sysctl_dev_name_is_allowed(const char *name)
static inline bool inet_port_requires_bind_service(struct net *net, unsigned short port) { - return port < net->ipv4.sysctl_ip_prot_sock; + return port < READ_ONCE(net->ipv4.sysctl_ip_prot_sock); }
#else diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 6b718688865e..344cdcd5a7d5 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -88,7 +88,7 @@ static int ipv4_local_port_range(struct ctl_table *table, int write, * port limit. */ if ((range[1] < range[0]) || - (range[0] < net->ipv4.sysctl_ip_prot_sock)) + (range[0] < READ_ONCE(net->ipv4.sysctl_ip_prot_sock))) ret = -EINVAL; else set_local_port_range(net, range); @@ -114,7 +114,7 @@ static int ipv4_privileged_ports(struct ctl_table *table, int write, .extra2 = &ip_privileged_port_max, };
- pports = net->ipv4.sysctl_ip_prot_sock; + pports = READ_ONCE(net->ipv4.sysctl_ip_prot_sock);
ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
@@ -126,7 +126,7 @@ static int ipv4_privileged_ports(struct ctl_table *table, int write, if (range[0] < pports) ret = -EINVAL; else - net->ipv4.sysctl_ip_prot_sock = pports; + WRITE_ONCE(net->ipv4.sysctl_ip_prot_sock, pports); }
return ret;