Messages in this thread Patch in this message | | | From | William Pitcock <> | Subject | [patch] sysctl to allow non-superusers to use ports <= 1023 without setpcaps | Date | Fri, 22 Sep 2006 00:56:36 -0500 |
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Hello everyone,
This is a patch that adds a sysctl, net.ipv4.allow_lowport_nonsuperuser_bind, which removes the setpcaps/ sucaps/etc requirement for allowing a non-superuser process to use ports <= 1023.
The patch is below:
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index e4b1a4d..c3f7c3c 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -411,6 +411,7 @@ enum NET_IPV4_TCP_WORKAROUND_SIGNED_WINDOWS=115, NET_TCP_DMA_COPYBREAK=116, NET_TCP_SLOW_START_AFTER_IDLE=117, + NET_IPV4_ALLOW_LOWPORT_BIND_NONSUPERUSER=118, }; enum { diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index c84a320..a2ea829 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -394,6 +394,11 @@ int inet_release(struct socket *sock) /* It is off by default, see below. */ int sysctl_ip_nonlocal_bind; +/* When this is enabled, it allows normal users to bind to ports <= 1023. + * This is set by the net.ipv4.allow_lowport_bind_nonsuperuser sysctl value. + */ +int sysctl_ip_allow_lowport_bind_nonsuperuser; + int inet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) { struct sockaddr_in *addr = (struct sockaddr_in *)uaddr; @@ -432,7 +437,8 @@ int inet_bind(struct socket *sock, struc snum = ntohs(addr->sin_port); err = -EACCES; - if (snum && snum < PROT_SOCK && !capable(CAP_NET_BIND_SERVICE)) + if (!sysctl_ip_allow_lowport_bind_nonsuperuser && snum && snum < PROT_SOCK && + !capable(CAP_NET_BIND_SERVICE)) goto out; /* We keep a pair of addresses. rcv_saddr is the one @@ -1412,3 +1418,4 @@ EXPORT_SYMBOL(inet_stream_ops); EXPORT_SYMBOL(inet_unregister_protosw); EXPORT_SYMBOL(net_statistics); EXPORT_SYMBOL(sysctl_ip_nonlocal_bind); +EXPORT_SYMBOL(sysctl_ip_allow_lowport_bind_nonsuperuser); diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 70cea9d..c57ef3a 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -20,6 +20,7 @@ #include <net/tcp.h> /* From af_inet.c */ extern int sysctl_ip_nonlocal_bind; +extern int sysctl_ip_allow_lowport_bind_nonsuperuser; #ifdef CONFIG_SYSCTL static int zero; @@ -197,6 +198,14 @@ ctl_table ipv4_table[] = { .proc_handler = &proc_dointvec }, { + .ctl_name = NET_IPV4_ALLOW_LOWPORT_BIND_NONSUPERUSER, + .procname = "allow_lowport_bind_nonsuperuser", + .data = &sysctl_ip_allow_lowport_bind_nonsuperuser, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &proc_dointvec + }, + { .ctl_name = NET_IPV4_TCP_SYN_RETRIES, .procname = "tcp_syn_retries", .data = &sysctl_tcp_syn_retries,
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