[PATCH] RFC: Don't override system's default ping_group_range for pasta

[PATCH] RFC: Don't override system's default ping_group_range for pasta

[David Gibson]

When spawning a command, pasta sets the net.ipv4.ping_group_range sysctl
to 0 0, meaning only group 0 can use ping sockets within the namespace.
Since group 0 is the only one we map in the userns, that's equivalent to
anyone being able to use ping sockets.

Although the kernel default for this is 1 0 (nobody can use ping sockets),
common distros - at least ones using systemd or even just systemd-udevd -
appear to set it to "0	2147483647" meaning effectively anyone can use
ping sockets.

There's no obvious reason that we need to override the system's default
behaviour here.  The override was introduced in 32d07f5e5 ("passt, pasta:
Completely avoid dynamic memory allocation") as part of a large chunk which
kind of looks like it was meant to be in another patch, so the git history
isn't particularly informative.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 pasta.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/pasta.c b/pasta.c
index 5aa56b78..4248b508 100644
--- a/pasta.c
+++ b/pasta.c
@@ -198,9 +198,6 @@ static int pasta_spawn_cmd(void *arg)
 	if (mount("", "/proc", "proc", 0, NULL))
 		warn_perror("Couldn't mount /proc");
 
-	if (write_file("/proc/sys/net/ipv4/ping_group_range", "0 0"))
-		warn("Cannot set ping_group_range, ICMP requests might fail");
-
 	a = (const struct pasta_spawn_cmd_arg *)arg;
 
 	conf_hostname_len = strlen(a->c->hostname);
-- 
2.55.0