diff options
| author | Pablo Neira Ayuso <pablo@netfilter.org> | 2023-04-07 16:21:57 -0600 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2023-04-24 22:48:42 +0200 |
| commit | 375505a4a8068bf7cb623e18c3aedb831c17fd0e (patch) | |
| tree | ef076f2fbef1eaca39c65eddcc0b9f5cd3a9b9cc /src/libnftables.c | |
| parent | 6231d3fa4af1e403555a6d4a139b3867218fab74 (diff) | |
mnl: set SO_SNDBUF before SO_SNDBUFFORCE
Set SO_SNDBUF before SO_SNDBUFFORCE: Unpriviledged user namespace does
not have CAP_NET_ADMIN on the host (user_init_ns) namespace.
SO_SNDBUF always succeeds in Linux, always try SO_SNDBUFFORCE after it.
Moreover, suggest the user to bump socket limits if EMSGSIZE after
having see EPERM previously, when calling SO_SNDBUFFORCE.
Provide a hint to the user too:
# nft -f test.nft
netlink: Error: Could not process rule: Message too long
Please, rise /proc/sys/net/core/wmem_max on the host namespace. Hint: 4194304 bytes
Dave Pfike says:
Prior to this patch, nft inside a systemd-nspawn container was failing
to install my ruleset (which includes a large-ish map), with the error
netlink: Error: Could not process rule: Message too long
strace reveals:
setsockopt(3, SOL_SOCKET, SO_SNDBUFFORCE, [524288], 4) = -1 EPERM (Operation not permitted)
This is despite the nspawn process supposedly having CAP_NET_ADMIN.
A web search reveals at least one other user having the same issue:
https://old.reddit.com/r/Proxmox/comments/scnoav/lxc_container_debian_11_nftables_geoblocking/
Reported-by: Dave Pifke <dave@pifke.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'src/libnftables.c')
| -rw-r--r-- | src/libnftables.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/src/libnftables.c b/src/libnftables.c index 4f538c44..de16d203 100644 --- a/src/libnftables.c +++ b/src/libnftables.c @@ -55,6 +55,13 @@ static int nft_netlink(struct nft_ctx *nft, ret = mnl_batch_talk(&ctx, &err_list, num_cmds); if (ret < 0) { + if (ctx.maybe_emsgsize && errno == EMSGSIZE) { + netlink_io_error(&ctx, NULL, + "Could not process rule: %s\n" + "Please, rise /proc/sys/net/core/wmem_max on the host namespace. Hint: %d bytes", + strerror(errno), round_pow_2(ctx.maybe_emsgsize)); + goto out; + } netlink_io_error(&ctx, NULL, "Could not process rule: %s", strerror(errno)); goto out; |