* [PATCH net-next v2 1/2] net: make net.core.{r,w}mem_{default,max} namespaced
2024-05-30 23:27 [PATCH net-next v2 0/2] net: visibility of memory limits in netns technoboy85
@ 2024-05-30 23:27 ` technoboy85
2024-05-31 8:12 ` Eric Dumazet
2024-05-31 22:11 ` Shakeel Butt
2024-05-30 23:27 ` [PATCH net-next v2 2/2] selftests: net: tests net.core.{r,w}mem_{default,max} sysctls in a netns technoboy85
2024-06-01 23:20 ` [PATCH net-next v2 0/2] net: visibility of memory limits in netns patchwork-bot+netdevbpf
2 siblings, 2 replies; 6+ messages in thread
From: technoboy85 @ 2024-05-30 23:27 UTC (permalink / raw)
To: netdev
Cc: David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
Shuah Khan, Shakeel Butt, linux-kernel, linux-kselftest,
Matteo Croce
From: Matteo Croce <teknoraver@meta.com>
The following sysctl are global and can't be read from a netns:
net.core.rmem_default
net.core.rmem_max
net.core.wmem_default
net.core.wmem_max
Make the following sysctl parameters available readonly from within a
network namespace, allowing a container to read them.
Signed-off-by: Matteo Croce <teknoraver@meta.com>
---
net/core/sysctl_net_core.c | 75 +++++++++++++++++++++-----------------
1 file changed, 42 insertions(+), 33 deletions(-)
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index c9fb9ad87485..2079000691e2 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -382,38 +382,6 @@ proc_dolongvec_minmax_bpf_restricted(struct ctl_table *table, int write,
#endif
static struct ctl_table net_core_table[] = {
- {
- .procname = "wmem_max",
- .data = &sysctl_wmem_max,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = proc_dointvec_minmax,
- .extra1 = &min_sndbuf,
- },
- {
- .procname = "rmem_max",
- .data = &sysctl_rmem_max,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = proc_dointvec_minmax,
- .extra1 = &min_rcvbuf,
- },
- {
- .procname = "wmem_default",
- .data = &sysctl_wmem_default,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = proc_dointvec_minmax,
- .extra1 = &min_sndbuf,
- },
- {
- .procname = "rmem_default",
- .data = &sysctl_rmem_default,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = proc_dointvec_minmax,
- .extra1 = &min_rcvbuf,
- },
{
.procname = "mem_pcpu_rsv",
.data = &net_hotdata.sysctl_mem_pcpu_rsv,
@@ -697,6 +665,41 @@ static struct ctl_table netns_core_table[] = {
.extra2 = SYSCTL_ONE,
.proc_handler = proc_dou8vec_minmax,
},
+ /* sysctl_core_net_init() will set the values after this
+ * to readonly in network namespaces
+ */
+ {
+ .procname = "wmem_max",
+ .data = &sysctl_wmem_max,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &min_sndbuf,
+ },
+ {
+ .procname = "rmem_max",
+ .data = &sysctl_rmem_max,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &min_rcvbuf,
+ },
+ {
+ .procname = "wmem_default",
+ .data = &sysctl_wmem_default,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &min_sndbuf,
+ },
+ {
+ .procname = "rmem_default",
+ .data = &sysctl_rmem_default,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &min_rcvbuf,
+ },
};
static int __init fb_tunnels_only_for_init_net_sysctl_setup(char *str)
@@ -724,8 +727,14 @@ static __net_init int sysctl_core_net_init(struct net *net)
if (tbl == NULL)
goto err_dup;
- for (i = 0; i < table_size; ++i)
+ for (i = 0; i < table_size; ++i) {
+ if (tbl[i].data == &sysctl_wmem_max)
+ break;
+
tbl[i].data += (char *)net - (char *)&init_net;
+ }
+ for (; i < table_size; ++i)
+ tbl[i].mode &= ~0222;
}
net->core.sysctl_hdr = register_net_sysctl_sz(net, "net/core", tbl, table_size);
--
2.45.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH net-next v2 2/2] selftests: net: tests net.core.{r,w}mem_{default,max} sysctls in a netns
2024-05-30 23:27 [PATCH net-next v2 0/2] net: visibility of memory limits in netns technoboy85
2024-05-30 23:27 ` [PATCH net-next v2 1/2] net: make net.core.{r,w}mem_{default,max} namespaced technoboy85
@ 2024-05-30 23:27 ` technoboy85
2024-06-01 23:20 ` [PATCH net-next v2 0/2] net: visibility of memory limits in netns patchwork-bot+netdevbpf
2 siblings, 0 replies; 6+ messages in thread
From: technoboy85 @ 2024-05-30 23:27 UTC (permalink / raw)
To: netdev
Cc: David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
Shuah Khan, Shakeel Butt, linux-kernel, linux-kselftest,
Matteo Croce
From: Matteo Croce <teknoraver@meta.com>
Add a selftest which checks that the sysctl is present in a netns,
that the value is read from the init one, and that it's readonly.
Signed-off-by: Matteo Croce <teknoraver@meta.com>
---
tools/testing/selftests/net/Makefile | 1 +
tools/testing/selftests/net/netns-sysctl.sh | 40 +++++++++++++++++++++
2 files changed, 41 insertions(+)
create mode 100755 tools/testing/selftests/net/netns-sysctl.sh
diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index bd01e4a0be2c..6da63d1831c1 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -53,6 +53,7 @@ TEST_PROGS += bind_bhash.sh
TEST_PROGS += ip_local_port_range.sh
TEST_PROGS += rps_default_mask.sh
TEST_PROGS += big_tcp.sh
+TEST_PROGS += netns-sysctl.sh
TEST_PROGS_EXTENDED := toeplitz_client.sh toeplitz.sh
TEST_GEN_FILES = socket nettest
TEST_GEN_FILES += psock_fanout psock_tpacket msg_zerocopy reuseport_addr_any
diff --git a/tools/testing/selftests/net/netns-sysctl.sh b/tools/testing/selftests/net/netns-sysctl.sh
new file mode 100755
index 000000000000..45c34a3b9aae
--- /dev/null
+++ b/tools/testing/selftests/net/netns-sysctl.sh
@@ -0,0 +1,40 @@
+#!/bin/bash -e
+# SPDX-License-Identifier: GPL-2.0
+#
+# This test checks that the network buffer sysctls are present
+# in a network namespaces, and that they are readonly.
+
+source lib.sh
+
+cleanup() {
+ cleanup_ns $test_ns
+}
+
+trap cleanup EXIT
+
+fail() {
+ echo "ERROR: $*" >&2
+ exit 1
+}
+
+setup_ns test_ns
+
+for sc in {r,w}mem_{default,max}; do
+ # check that this is writable in a netns
+ [ -w "/proc/sys/net/core/$sc" ] ||
+ fail "$sc isn't writable in the init netns!"
+
+ # change the value in the host netns
+ sysctl -qw "net.core.$sc=300000" ||
+ fail "Can't write $sc in init netns!"
+
+ # check that the value is read from the init netns
+ [ "$(ip netns exec $test_ns sysctl -n "net.core.$sc")" -eq 300000 ] ||
+ fail "Value for $sc mismatch!"
+
+ # check that this isn't writable in a netns
+ ip netns exec $test_ns [ -w "/proc/sys/net/core/$sc" ] &&
+ fail "$sc is writable in a netns!"
+done
+
+echo 'Test passed OK'
--
2.45.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH net-next v2 0/2] net: visibility of memory limits in netns
2024-05-30 23:27 [PATCH net-next v2 0/2] net: visibility of memory limits in netns technoboy85
2024-05-30 23:27 ` [PATCH net-next v2 1/2] net: make net.core.{r,w}mem_{default,max} namespaced technoboy85
2024-05-30 23:27 ` [PATCH net-next v2 2/2] selftests: net: tests net.core.{r,w}mem_{default,max} sysctls in a netns technoboy85
@ 2024-06-01 23:20 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 6+ messages in thread
From: patchwork-bot+netdevbpf @ 2024-06-01 23:20 UTC (permalink / raw)
To: Matteo Croce
Cc: netdev, davem, edumazet, kuba, pabeni, shuah, shakeel.butt,
linux-kernel, linux-kselftest, teknoraver
Hello:
This series was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:
On Fri, 31 May 2024 01:27:20 +0200 you wrote:
> From: Matteo Croce <teknoraver@meta.com>
>
> Some programs need to know the size of the network buffers to operate
> correctly, export the following sysctls read-only in network namespaces:
>
> - net.core.rmem_default
> - net.core.rmem_max
> - net.core.wmem_default
> - net.core.wmem_max
>
> [...]
Here is the summary with links:
- [net-next,v2,1/2] net: make net.core.{r,w}mem_{default,max} namespaced
https://git.kernel.org/netdev/net-next/c/19249c0724f2
- [net-next,v2,2/2] selftests: net: tests net.core.{r,w}mem_{default,max} sysctls in a netns
https://git.kernel.org/netdev/net-next/c/5b5233fb81bf
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] 6+ messages in thread