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* [PATCH net-next] net: ipv4: add capability check for net administration
@ 2021-07-20  1:43 cgel.zte
  2021-07-20 14:20 ` patchwork-bot+netdevbpf
  0 siblings, 1 reply; 2+ messages in thread
From: cgel.zte @ 2021-07-20  1:43 UTC (permalink / raw)
  To: kuba
  Cc: davem, yoshfuji, dsahern, netdev, linux-kernel, Yang Yang, Zeal Robot

From: Yang Yang <yang.yang29@zte.com.cn>

Root in init user namespace can modify /proc/sys/net/ipv4/ip_forward
without CAP_NET_ADMIN, this doesn't follow the principle of
capabilities. For example, let's take a look at netdev_store(),
root can't modify netdev attribute without CAP_NET_ADMIN.
So let's keep the consistency of permission check logic.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
---
 net/ipv4/devinet.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 73721a4448bd..6238ab2dd3d1 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -2424,11 +2424,15 @@ static int devinet_sysctl_forward(struct ctl_table *ctl, int write,
 	int *valp = ctl->data;
 	int val = *valp;
 	loff_t pos = *ppos;
-	int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
+	struct net *net = ctl->extra2;
+	int ret;
 
-	if (write && *valp != val) {
-		struct net *net = ctl->extra2;
+	if (write && !ns_capable(net->user_ns, CAP_NET_ADMIN))
+		return -EPERM;
+
+	ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
 
+	if (write && *valp != val) {
 		if (valp != &IPV4_DEVCONF_DFLT(net, FORWARDING)) {
 			if (!rtnl_trylock()) {
 				/* Restore the original values before restarting */
-- 
2.25.1


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH net-next] net: ipv4: add capability check for net administration
  2021-07-20  1:43 [PATCH net-next] net: ipv4: add capability check for net administration cgel.zte
@ 2021-07-20 14:20 ` patchwork-bot+netdevbpf
  0 siblings, 0 replies; 2+ messages in thread
From: patchwork-bot+netdevbpf @ 2021-07-20 14:20 UTC (permalink / raw)
  To: None
  Cc: kuba, davem, yoshfuji, dsahern, netdev, linux-kernel,
	yang.yang29, zealci

Hello:

This patch was applied to netdev/net-next.git (refs/heads/master):

On Mon, 19 Jul 2021 18:43:28 -0700 you wrote:
> From: Yang Yang <yang.yang29@zte.com.cn>
> 
> Root in init user namespace can modify /proc/sys/net/ipv4/ip_forward
> without CAP_NET_ADMIN, this doesn't follow the principle of
> capabilities. For example, let's take a look at netdev_store(),
> root can't modify netdev attribute without CAP_NET_ADMIN.
> So let's keep the consistency of permission check logic.
> 
> [...]

Here is the summary with links:
  - [net-next] net: ipv4: add capability check for net administration
    https://git.kernel.org/netdev/net-next/c/8292d7f6e871

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html



^ permalink raw reply	[flat|nested] 2+ messages in thread

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2021-07-20 14:20 ` patchwork-bot+netdevbpf

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