linux/net
Vladimir Oltean 1f922d9e37 Revert "net: procfs: add seq_puts() statement for dev_mcast"
This reverts commit ec18e84554.

It turns out that there are user space programs which got broken by that
change. One example is the "ifstat" program shipped by Debian:
https://packages.debian.org/source/bullseye/ifstat
which, confusingly enough, seems to not have anything in common with the
much more familiar (at least to me) ifstat program from iproute2:
https://git.kernel.org/pub/scm/network/iproute2/iproute2.git/tree/misc/ifstat.c

root@debian:~# ifstat
ifstat: /proc/net/dev: unsupported format.

This change modified the header (first two lines of text) in
/proc/net/dev so that it looks like this:

root@debian:~# cat /proc/net/dev
Interface|                            Receive                                       |                                 Transmit
         |            bytes      packets errs   drop fifo frame compressed multicast|            bytes      packets errs   drop fifo colls carrier compressed
       lo:            97400         1204    0      0    0     0          0         0            97400         1204    0      0    0     0       0          0
    bond0:                0            0    0      0    0     0          0         0                0            0    0      0    0     0       0          0
     sit0:                0            0    0      0    0     0          0         0                0            0    0      0    0     0       0          0
     eno2:          5002206         6651    0      0    0     0          0         0        105518642      1465023    0      0    0     0       0          0
     swp0:           134531         2448    0      0    0     0          0         0         99599598      1464381    0      0    0     0       0          0
     swp1:                0            0    0      0    0     0          0         0                0            0    0      0    0     0       0          0
     swp2:          4867675         4203    0      0    0     0          0         0            58134          631    0      0    0     0       0          0
    sw0p0:                0            0    0      0    0     0          0         0                0            0    0      0    0     0       0          0
    sw0p1:           124739         2448    0   1422    0     0          0         0         93741184      1464369    0      0    0     0       0          0
    sw0p2:                0            0    0      0    0     0          0         0                0            0    0      0    0     0       0          0
    sw2p0:          4850863         4203    0      0    0     0          0         0            54722          619    0      0    0     0       0          0
    sw2p1:                0            0    0      0    0     0          0         0                0            0    0      0    0     0       0          0
    sw2p2:                0            0    0      0    0     0          0         0                0            0    0      0    0     0       0          0
    sw2p3:                0            0    0      0    0     0          0         0                0            0    0      0    0     0       0          0
      br0:            10508          212    0    212    0     0          0       212         61369558       958857    0      0    0     0       0          0

whereas before it looked like this:

root@debian:~# cat /proc/net/dev
Inter-|   Receive                                                |  Transmit
 face |bytes    packets errs drop fifo frame compressed multicast|bytes    packets errs drop fifo colls carrier compressed
    lo:   13160     164    0    0    0     0          0         0    13160     164    0    0    0     0       0          0
 bond0:       0       0    0    0    0     0          0         0        0       0    0    0    0     0       0          0
  sit0:       0       0    0    0    0     0          0         0        0       0    0    0    0     0       0          0
  eno2:   30824     268    0    0    0     0          0         0     3332      37    0    0    0     0       0          0
  swp0:       0       0    0    0    0     0          0         0        0       0    0    0    0     0       0          0
  swp1:       0       0    0    0    0     0          0         0        0       0    0    0    0     0       0          0
  swp2:   30824     268    0    0    0     0          0         0     2428      27    0    0    0     0       0          0
 sw0p0:       0       0    0    0    0     0          0         0        0       0    0    0    0     0       0          0
 sw0p1:       0       0    0    0    0     0          0         0        0       0    0    0    0     0       0          0
 sw0p2:       0       0    0    0    0     0          0         0        0       0    0    0    0     0       0          0
 sw2p0:   29752     268    0    0    0     0          0         0     1564      17    0    0    0     0       0          0
 sw2p1:       0       0    0    0    0     0          0         0        0       0    0    0    0     0       0          0
 sw2p2:       0       0    0    0    0     0          0         0        0       0    0    0    0     0       0          0
 sw2p3:       0       0    0    0    0     0          0         0        0       0    0    0    0     0       0          0

The reason why the ifstat shipped by Debian (v1.1, with a Debian patch
upgrading it to 1.1-8.1 at the time of writing) is broken is because its
"proc" driver/backend parses the header very literally:

main/drivers.c#L825
  if (!data->checked && strncmp(buf, "Inter-|", 7))
    goto badproc;

and there's no way in which the header can be changed such that programs
parsing like that would not get broken.

Even if we fix this ancient and very "lightly" maintained program to
parse the text output of /proc/net/dev in a more sensible way, this
story seems bound to repeat again with other programs, and modifying
them all could cause more trouble than it's worth. On the other hand,
the reverted patch had no other reason than an aesthetic one, so
reverting it is the simplest way out.

I don't know what other distributions would be affected; the fact that
Debian doesn't ship the iproute2 version of the program (a different
code base altogether, which uses netlink and not /proc/net/dev) is
surprising in itself.

Fixes: ec18e84554 ("net: procfs: add seq_puts() statement for dev_mcast")
Link: https://lore.kernel.org/netdev/20211009163511.vayjvtn3rrteglsu@skbuf/
Cc: Yajun Deng <yajun.deng@linux.dev>
Cc: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20211013001909.3164185-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-10-13 17:24:38 -07:00
..
6lowpan 6lowpan: iphc: Fix an off-by-one check of array index 2021-07-22 16:19:03 +02:00
9p net/9p: increase default msize to 128k 2021-09-05 08:36:44 +09:00
802 net: 802: remove dead leftover after ipx driver removal 2021-08-13 16:30:35 -07:00
8021q dev_ioctl: split out ndo_eth_ioctl 2021-07-27 20:11:45 +01:00
appletalk net: socket: rework compat_ifreq_ioctl() 2021-07-23 14:20:25 +01:00
atm
ax25 ax25: use skb_expand_head 2021-08-03 11:21:39 +01:00
batman-adv Kbuild updates for v5.15 2021-09-03 15:33:47 -07:00
bluetooth TTY / Serial patches for 5.15-rc1 2021-09-01 09:51:16 -07:00
bpf bpf, test, cgroup: Use sk_{alloc,free} for test cases 2021-09-28 09:29:28 +02:00
bpfilter
bridge net: bridge: fix under estimation in br_get_linkxstats_size() 2021-10-05 12:39:07 +01:00
caif net-caif: avoid user-triggerable WARN_ON(1) 2021-09-14 12:51:15 +01:00
can net: Remove redundant if statements 2021-08-05 13:27:50 +01:00
ceph
core Revert "net: procfs: add seq_puts() statement for dev_mcast" 2021-10-13 17:24:38 -07:00
dcb
dccp dccp: don't duplicate ccid when cloning dccp sock 2021-09-08 11:28:35 +01:00
decnet net: Remove redundant if statements 2021-08-05 13:27:50 +01:00
dns_resolver
dsa net: dsa: tag_ocelot_8021q: fix inability to inject STP BPDUs into BLOCKING ports 2021-10-12 17:35:19 -07:00
ethernet move netdev_boot_setup into Space.c 2021-08-03 13:05:26 +01:00
ethtool ethtool: extend coalesce setting uAPI with CQE mode 2021-08-24 07:38:29 -07:00
hsr
ieee802154 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-08-13 06:41:22 -07:00
ife
ipv4 net: prefer socket bound to interface when not in VRF 2021-10-07 07:27:55 -07:00
ipv6 ipv6: ioam: move the check for undefined bits 2021-10-12 11:49:49 +01:00
iucv net/iucv: Replace deprecated CPU-hotplug functions. 2021-08-09 10:13:32 +01:00
kcm
key
l2tp net/l2tp: Fix reference count leak in l2tp_udp_recv_core 2021-09-09 11:00:20 +01:00
l3mdev
lapb
llc net: Remove redundant if statements 2021-08-05 13:27:50 +01:00
mac80211 mac80211: check return value of rhashtable_init 2021-09-27 12:00:34 +02:00
mac802154 ieee802154: Remove redundant initialization of variable ret 2021-09-07 14:06:08 +01:00
mctp mctp: perform route destruction under RCU read lock 2021-09-08 11:29:16 +01:00
mpls mpls: defer ttl decrement in mpls_forward() 2021-07-23 17:17:56 +01:00
mptcp mptcp: fix possible stall on recvmsg() 2021-10-08 14:55:54 +01:00
ncsi net/ncsi: add get MAC address command to get Intel i210 MAC address 2021-09-01 17:18:56 -07:00
netfilter netfilter: nf_tables: honor NLM_F_CREATE and NLM_F_EXCL in event notification 2021-10-02 12:00:17 +02:00
netlabel net: fix NULL pointer reference in cipso_v4_doi_free 2021-08-30 12:23:18 +01:00
netlink netlink: annotate data races around nlk->bound 2021-10-05 13:11:09 +01:00
netrom net: Remove redundant if statements 2021-08-05 13:27:50 +01:00
nfc nfc: nci: fix the UAF of rf_conn_info object 2021-10-08 17:24:32 +01:00
nsh
openvswitch Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-08-19 18:09:18 -07:00
packet net/packet: clarify source of pr_*() messages 2021-09-10 10:00:59 +01:00
phonet net: Remove redundant if statements 2021-08-05 13:27:50 +01:00
psample
qrtr net: qrtr: revert check in qrtr_endpoint_post() 2021-09-02 11:37:02 +01:00
rds net/rds: dma_map_sg is entitled to merge entries 2021-08-18 15:35:50 -07:00
rfkill
rose
rxrpc net: RxRPC: make dependent Kconfig symbols be shown indented 2021-08-18 10:12:11 +01:00
sched mqprio: Correct stats in mqprio_dump_class_stats(). 2021-10-08 16:27:22 -07:00
sctp sctp: break out if skb_header_pointer returns NULL in sctp_rcv_ootb 2021-09-24 10:36:19 +01:00
smc net/smc: improved fix wait on already cleared link 2021-10-08 17:00:16 +01:00
strparser
sunrpc Bug fixes for NFSD error handling paths 2021-10-07 14:11:40 -07:00
switchdev net: make switchdev_bridge_port_{,unoffload} loosely coupled with the bridge 2021-08-04 12:35:07 +01:00
tipc tipc: increase timeout in tipc_sk_enqueue() 2021-09-13 12:43:10 +01:00
tls
unix af_unix: Rename UNIX-DGRAM to UNIX to maintain backwards compatability 2021-10-12 11:16:49 +01:00
vmw_vsock af_vsock: rename variables in receive loop 2021-09-06 02:25:16 -04:00
wireless cfg80211: use wiphy DFS domain if it is self-managed 2021-08-26 11:04:55 +02:00
x25
xdp
xfrm xfrm: fix rcu lock in xfrm_notify_userpolicy() 2021-09-23 10:11:12 +02:00
compat.c
devres.c
Kconfig mctp: Add MCTP base 2021-07-29 15:06:49 +01:00
Makefile mctp: Add MCTP base 2021-07-29 15:06:49 +01:00
socket.c Core: 2021-08-31 16:43:06 -07:00
sysctl_net.c