* [PATCH 6.10 092/121] netfilter: nft_socket: make cgroupsv2 matching work with namespaces
[not found] <20240916114228.914815055@linuxfoundation.org>
@ 2024-09-16 11:44 ` Greg Kroah-Hartman
2024-09-16 15:33 ` Pablo Neira Ayuso
0 siblings, 1 reply; 3+ messages in thread
From: Greg Kroah-Hartman @ 2024-09-16 11:44 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, cgroups, Nadia Pinaeva,
Florian Westphal, Pablo Neira Ayuso, Sasha Levin
6.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Florian Westphal <fw@strlen.de>
[ Upstream commit 7f3287db654395f9c5ddd246325ff7889f550286 ]
When running in container environmment, /sys/fs/cgroup/ might not be
the real root node of the sk-attached cgroup.
Example:
In container:
% stat /sys//fs/cgroup/
Device: 0,21 Inode: 2214 ..
% stat /sys/fs/cgroup/foo
Device: 0,21 Inode: 2264 ..
The expectation would be for:
nft add rule .. socket cgroupv2 level 1 "foo" counter
to match traffic from a process that got added to "foo" via
"echo $pid > /sys/fs/cgroup/foo/cgroup.procs".
However, 'level 3' is needed to make this work.
Seen from initial namespace, the complete hierarchy is:
% stat /sys/fs/cgroup/system.slice/docker-.../foo
Device: 0,21 Inode: 2264 ..
i.e. hierarchy is
0 1 2 3
/ -> system.slice -> docker-1... -> foo
... but the container doesn't know that its "/" is the "docker-1.."
cgroup. Current code will retrieve the 'system.slice' cgroup node
and store its kn->id in the destination register, so compare with
2264 ("foo" cgroup id) will not match.
Fetch "/" cgroup from ->init() and add its level to the level we try to
extract. cgroup root-level is 0 for the init-namespace or the level
of the ancestor that is exposed as the cgroup root inside the container.
In the above case, cgrp->level of "/" resolved in the container is 2
(docker-1...scope/) and request for 'level 1' will get adjusted
to fetch the actual level (3).
v2: use CONFIG_SOCK_CGROUP_DATA, eval function depends on it.
(kernel test robot)
Cc: cgroups@vger.kernel.org
Fixes: e0bb96db96f8 ("netfilter: nft_socket: add support for cgroupsv2")
Reported-by: Nadia Pinaeva <n.m.pinaeva@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/nft_socket.c | 41 +++++++++++++++++++++++++++++++++++---
1 file changed, 38 insertions(+), 3 deletions(-)
diff --git a/net/netfilter/nft_socket.c b/net/netfilter/nft_socket.c
index 765ffd6e06bc..12cdff640492 100644
--- a/net/netfilter/nft_socket.c
+++ b/net/netfilter/nft_socket.c
@@ -9,7 +9,8 @@
struct nft_socket {
enum nft_socket_keys key:8;
- u8 level;
+ u8 level; /* cgroupv2 level to extract */
+ u8 level_user; /* cgroupv2 level provided by userspace */
u8 len;
union {
u8 dreg;
@@ -53,6 +54,28 @@ nft_sock_get_eval_cgroupv2(u32 *dest, struct sock *sk, const struct nft_pktinfo
memcpy(dest, &cgid, sizeof(u64));
return true;
}
+
+/* process context only, uses current->nsproxy. */
+static noinline int nft_socket_cgroup_subtree_level(void)
+{
+ struct cgroup *cgrp = cgroup_get_from_path("/");
+ int level;
+
+ if (!cgrp)
+ return -ENOENT;
+
+ level = cgrp->level;
+
+ cgroup_put(cgrp);
+
+ if (WARN_ON_ONCE(level > 255))
+ return -ERANGE;
+
+ if (WARN_ON_ONCE(level < 0))
+ return -EINVAL;
+
+ return level;
+}
#endif
static struct sock *nft_socket_do_lookup(const struct nft_pktinfo *pkt)
@@ -174,9 +197,10 @@ static int nft_socket_init(const struct nft_ctx *ctx,
case NFT_SOCKET_MARK:
len = sizeof(u32);
break;
-#ifdef CONFIG_CGROUPS
+#ifdef CONFIG_SOCK_CGROUP_DATA
case NFT_SOCKET_CGROUPV2: {
unsigned int level;
+ int err;
if (!tb[NFTA_SOCKET_LEVEL])
return -EINVAL;
@@ -185,6 +209,17 @@ static int nft_socket_init(const struct nft_ctx *ctx,
if (level > 255)
return -EOPNOTSUPP;
+ err = nft_socket_cgroup_subtree_level();
+ if (err < 0)
+ return err;
+
+ priv->level_user = level;
+
+ level += err;
+ /* Implies a giant cgroup tree */
+ if (WARN_ON_ONCE(level > 255))
+ return -EOPNOTSUPP;
+
priv->level = level;
len = sizeof(u64);
break;
@@ -209,7 +244,7 @@ static int nft_socket_dump(struct sk_buff *skb,
if (nft_dump_register(skb, NFTA_SOCKET_DREG, priv->dreg))
return -1;
if (priv->key == NFT_SOCKET_CGROUPV2 &&
- nla_put_be32(skb, NFTA_SOCKET_LEVEL, htonl(priv->level)))
+ nla_put_be32(skb, NFTA_SOCKET_LEVEL, htonl(priv->level_user)))
return -1;
return 0;
}
--
2.43.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 6.10 092/121] netfilter: nft_socket: make cgroupsv2 matching work with namespaces
2024-09-16 11:44 ` [PATCH 6.10 092/121] netfilter: nft_socket: make cgroupsv2 matching work with namespaces Greg Kroah-Hartman
@ 2024-09-16 15:33 ` Pablo Neira Ayuso
2024-09-16 19:05 ` Greg Kroah-Hartman
0 siblings, 1 reply; 3+ messages in thread
From: Pablo Neira Ayuso @ 2024-09-16 15:33 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: stable, patches, cgroups, Nadia Pinaeva, Florian Westphal,
Sasha Levin
Hi Greg,
This needs a follow up incremental fix. Please, hold on with it.
I will ping you back once it is there.
Thanks
On Mon, Sep 16, 2024 at 01:44:26PM +0200, Greg Kroah-Hartman wrote:
> 6.10-stable review patch. If anyone has any objections, please let me know.
>
> ------------------
>
> From: Florian Westphal <fw@strlen.de>
>
> [ Upstream commit 7f3287db654395f9c5ddd246325ff7889f550286 ]
>
> When running in container environmment, /sys/fs/cgroup/ might not be
> the real root node of the sk-attached cgroup.
>
> Example:
>
> In container:
> % stat /sys//fs/cgroup/
> Device: 0,21 Inode: 2214 ..
> % stat /sys/fs/cgroup/foo
> Device: 0,21 Inode: 2264 ..
>
> The expectation would be for:
>
> nft add rule .. socket cgroupv2 level 1 "foo" counter
>
> to match traffic from a process that got added to "foo" via
> "echo $pid > /sys/fs/cgroup/foo/cgroup.procs".
>
> However, 'level 3' is needed to make this work.
>
> Seen from initial namespace, the complete hierarchy is:
>
> % stat /sys/fs/cgroup/system.slice/docker-.../foo
> Device: 0,21 Inode: 2264 ..
>
> i.e. hierarchy is
> 0 1 2 3
> / -> system.slice -> docker-1... -> foo
>
> ... but the container doesn't know that its "/" is the "docker-1.."
> cgroup. Current code will retrieve the 'system.slice' cgroup node
> and store its kn->id in the destination register, so compare with
> 2264 ("foo" cgroup id) will not match.
>
> Fetch "/" cgroup from ->init() and add its level to the level we try to
> extract. cgroup root-level is 0 for the init-namespace or the level
> of the ancestor that is exposed as the cgroup root inside the container.
>
> In the above case, cgrp->level of "/" resolved in the container is 2
> (docker-1...scope/) and request for 'level 1' will get adjusted
> to fetch the actual level (3).
>
> v2: use CONFIG_SOCK_CGROUP_DATA, eval function depends on it.
> (kernel test robot)
>
> Cc: cgroups@vger.kernel.org
> Fixes: e0bb96db96f8 ("netfilter: nft_socket: add support for cgroupsv2")
> Reported-by: Nadia Pinaeva <n.m.pinaeva@gmail.com>
> Signed-off-by: Florian Westphal <fw@strlen.de>
> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
> net/netfilter/nft_socket.c | 41 +++++++++++++++++++++++++++++++++++---
> 1 file changed, 38 insertions(+), 3 deletions(-)
>
> diff --git a/net/netfilter/nft_socket.c b/net/netfilter/nft_socket.c
> index 765ffd6e06bc..12cdff640492 100644
> --- a/net/netfilter/nft_socket.c
> +++ b/net/netfilter/nft_socket.c
> @@ -9,7 +9,8 @@
>
> struct nft_socket {
> enum nft_socket_keys key:8;
> - u8 level;
> + u8 level; /* cgroupv2 level to extract */
> + u8 level_user; /* cgroupv2 level provided by userspace */
> u8 len;
> union {
> u8 dreg;
> @@ -53,6 +54,28 @@ nft_sock_get_eval_cgroupv2(u32 *dest, struct sock *sk, const struct nft_pktinfo
> memcpy(dest, &cgid, sizeof(u64));
> return true;
> }
> +
> +/* process context only, uses current->nsproxy. */
> +static noinline int nft_socket_cgroup_subtree_level(void)
> +{
> + struct cgroup *cgrp = cgroup_get_from_path("/");
> + int level;
> +
> + if (!cgrp)
> + return -ENOENT;
> +
> + level = cgrp->level;
> +
> + cgroup_put(cgrp);
> +
> + if (WARN_ON_ONCE(level > 255))
> + return -ERANGE;
> +
> + if (WARN_ON_ONCE(level < 0))
> + return -EINVAL;
> +
> + return level;
> +}
> #endif
>
> static struct sock *nft_socket_do_lookup(const struct nft_pktinfo *pkt)
> @@ -174,9 +197,10 @@ static int nft_socket_init(const struct nft_ctx *ctx,
> case NFT_SOCKET_MARK:
> len = sizeof(u32);
> break;
> -#ifdef CONFIG_CGROUPS
> +#ifdef CONFIG_SOCK_CGROUP_DATA
> case NFT_SOCKET_CGROUPV2: {
> unsigned int level;
> + int err;
>
> if (!tb[NFTA_SOCKET_LEVEL])
> return -EINVAL;
> @@ -185,6 +209,17 @@ static int nft_socket_init(const struct nft_ctx *ctx,
> if (level > 255)
> return -EOPNOTSUPP;
>
> + err = nft_socket_cgroup_subtree_level();
> + if (err < 0)
> + return err;
> +
> + priv->level_user = level;
> +
> + level += err;
> + /* Implies a giant cgroup tree */
> + if (WARN_ON_ONCE(level > 255))
> + return -EOPNOTSUPP;
> +
> priv->level = level;
> len = sizeof(u64);
> break;
> @@ -209,7 +244,7 @@ static int nft_socket_dump(struct sk_buff *skb,
> if (nft_dump_register(skb, NFTA_SOCKET_DREG, priv->dreg))
> return -1;
> if (priv->key == NFT_SOCKET_CGROUPV2 &&
> - nla_put_be32(skb, NFTA_SOCKET_LEVEL, htonl(priv->level)))
> + nla_put_be32(skb, NFTA_SOCKET_LEVEL, htonl(priv->level_user)))
> return -1;
> return 0;
> }
> --
> 2.43.0
>
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 6.10 092/121] netfilter: nft_socket: make cgroupsv2 matching work with namespaces
2024-09-16 15:33 ` Pablo Neira Ayuso
@ 2024-09-16 19:05 ` Greg Kroah-Hartman
0 siblings, 0 replies; 3+ messages in thread
From: Greg Kroah-Hartman @ 2024-09-16 19:05 UTC (permalink / raw)
To: Pablo Neira Ayuso
Cc: stable, patches, cgroups, Nadia Pinaeva, Florian Westphal,
Sasha Levin
On Mon, Sep 16, 2024 at 05:33:33PM +0200, Pablo Neira Ayuso wrote:
> Hi Greg,
>
> This needs a follow up incremental fix. Please, hold on with it.
>
> I will ping you back once it is there.
Thanks for letting us know, now dropped from all queues.
greg k-h
^ permalink raw reply [flat|nested] 3+ messages in thread
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2024-09-16 11:44 ` [PATCH 6.10 092/121] netfilter: nft_socket: make cgroupsv2 matching work with namespaces Greg Kroah-Hartman
2024-09-16 15:33 ` Pablo Neira Ayuso
2024-09-16 19:05 ` Greg Kroah-Hartman
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