[PATCH] net: change capability used by socket options IP{,V6}_TRANSPARENT
From: Maciej Żenczykowski <hidden>
Date: 2011-10-17 22:16:39
Subsystem:
capabilities, networking [general], networking [ipv4/ipv6], the rest · Maintainers:
Serge Hallyn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
From: Maciej Żenczykowski <redacted>
Up till now the IP{,V6}_TRANSPARENT socket options (which actually set
the same bit in the socket struct) have required CAP_NET_ADMIN
privileges to set or clear the option.
- we make clearing the bit not require any privileges.
- we deprecate using CAP_NET_ADMIN for this purpose.
- we allow CAP_NET_RAW to set this bit, because raw
sockets already effectively allow you to emulate socket
transparency.
- we print a warning (but allow it) if you try to set the socket
option with CAP_NET_ADMIN privs, but without CAP_NET_RAW.
Signed-off-by: Maciej Żenczykowski <redacted>
---
include/linux/capability.h | 3 ++-
net/ipv4/ip_sockglue.c | 20 ++++++++++++++++----
net/ipv6/ipv6_sockglue.c | 23 ++++++++++++++++++-----
3 files changed, 36 insertions(+), 10 deletions(-)
diff --git a/include/linux/capability.h b/include/linux/capability.h
index c421123..ce34ae3 100644
--- a/include/linux/capability.h
+++ b/include/linux/capability.h@@ -198,7 +198,7 @@ struct cpu_vfs_cap_data { /* Allow modification of routing tables */ /* Allow setting arbitrary process / process group ownership on sockets */ -/* Allow binding to any address for transparent proxying */ +/* Allow binding to any address for transparent proxying (deprecated) */ /* Allow setting TOS (type of service) */ /* Allow setting promiscuous mode */ /* Allow clearing driver statistics */
@@ -210,6 +210,7 @@ struct cpu_vfs_cap_data { /* Allow use of RAW sockets */ /* Allow use of PACKET sockets */ +/* Allow binding to any address for transparent proxying */ #define CAP_NET_RAW 13
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 8905e92..74f7d30 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c@@ -961,12 +961,24 @@ mc_msf_out: break; case IP_TRANSPARENT: - if (!capable(CAP_NET_ADMIN)) { - err = -EPERM; - break; - } if (optlen < 1) goto e_inval; + /* Always allow clearing the transparent proxy socket option. + * The pre-3.2 permission for setting this was CAP_NET_ADMIN, + * and this is still supported - but deprecated. As of Linux + * 3.2 the proper permission is CAP_NET_RAW. + */ + if (!!val && !capable(CAP_NET_RAW)) { + if (!capable(CAP_NET_ADMIN)) { + err = -EPERM; + break; + } + printk_once(KERN_WARNING "%s (%d): " + "deprecated: attempt to set socket option " + "IP_TRANSPARENT with CAP_NET_ADMIN but " + "without CAP_NET_RAW.\n", + current->comm, task_pid_nr(current)); + } inet->transparent = !!val; break;
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 2fbda5f..7c4f5ce 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c@@ -343,13 +343,26 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname, break; case IPV6_TRANSPARENT: - if (!capable(CAP_NET_ADMIN)) { - retv = -EPERM; - break; - } if (optlen < sizeof(int)) goto e_inval; - /* we don't have a separate transparent bit for IPV6 we use the one in the IPv4 socket */ + /* Always allow clearing the transparent proxy socket option. + * The pre-3.2 permission for setting this was CAP_NET_ADMIN, + * and this is still supported - but deprecated. As of Linux + * 3.2 the proper permission is CAP_NET_RAW. + */ + if (valbool && !capable(CAP_NET_RAW)) { + if (!capable(CAP_NET_ADMIN)) { + retv = -EPERM; + break; + } + printk_once(KERN_WARNING "%s (%d): " + "deprecated: attempt to set socket option " + "IPV6_TRANSPARENT with CAP_NET_ADMIN but " + "without CAP_NET_RAW.\n", + current->comm, task_pid_nr(current)); + } + /* we don't have a separate transparent bit for IPv6, + * so we just use the one in the IPv4 socket */ inet_sk(sk)->transparent = valbool; retv = 0; break;
--
1.7.3.1