linux/net/core
Alexey Kodanev c48cf4f27d net: sysctl_net_core: check SNDBUF and RCVBUF for min length
[ Upstream commit b1cb59cf2e ]

sysctl has sysctl.net.core.rmem_*/wmem_* parameters which can be
set to incorrect values. Given that 'struct sk_buff' allocates from
rcvbuf, incorrectly set buffer length could result to memory
allocation failures. For example, set them as follows:

    # sysctl net.core.rmem_default=64
      net.core.wmem_default = 64
    # sysctl net.core.wmem_default=64
      net.core.wmem_default = 64
    # ping localhost -s 1024 -i 0 > /dev/null

This could result to the following failure:

skbuff: skb_over_panic: text:ffffffff81628db4 len:-32 put:-32
head:ffff88003a1cc200 data:ffff88003a1cc200 tail:0xffffffe0 end:0xc0 dev:<NULL>
kernel BUG at net/core/skbuff.c:102!
invalid opcode: 0000 [#1] SMP
...
task: ffff88003b7f5550 ti: ffff88003ae88000 task.ti: ffff88003ae88000
RIP: 0010:[<ffffffff8155fbd1>]  [<ffffffff8155fbd1>] skb_put+0xa1/0xb0
RSP: 0018:ffff88003ae8bc68  EFLAGS: 00010296
RAX: 000000000000008d RBX: 00000000ffffffe0 RCX: 0000000000000000
RDX: ffff88003fdcf598 RSI: ffff88003fdcd9c8 RDI: ffff88003fdcd9c8
RBP: ffff88003ae8bc88 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 00000000000002b2 R12: 0000000000000000
R13: 0000000000000000 R14: ffff88003d3f7300 R15: ffff88000012a900
FS:  00007fa0e2b4a840(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000d0f7e0 CR3: 000000003b8fb000 CR4: 00000000000006f0
Stack:
 ffff88003a1cc200 00000000ffffffe0 00000000000000c0 ffffffff818cab1d
 ffff88003ae8bd68 ffffffff81628db4 ffff88003ae8bd48 ffff88003b7f5550
 ffff880031a09408 ffff88003b7f5550 ffff88000012aa48 ffff88000012ab00
Call Trace:
 [<ffffffff81628db4>] unix_stream_sendmsg+0x2c4/0x470
 [<ffffffff81556f56>] sock_write_iter+0x146/0x160
 [<ffffffff811d9612>] new_sync_write+0x92/0xd0
 [<ffffffff811d9cd6>] vfs_write+0xd6/0x180
 [<ffffffff811da499>] SyS_write+0x59/0xd0
 [<ffffffff81651532>] system_call_fastpath+0x12/0x17
Code: 00 00 48 89 44 24 10 8b 87 c8 00 00 00 48 89 44 24 08 48 8b 87 d8 00
      00 00 48 c7 c7 30 db 91 81 48 89 04 24 31 c0 e8 4f a8 0e 00 <0f> 0b
      eb fe 66 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 48 83
RIP  [<ffffffff8155fbd1>] skb_put+0xa1/0xb0
RSP <ffff88003ae8bc68>
Kernel panic - not syncing: Fatal exception

Moreover, the possible minimum is 1, so we can get another kernel panic:
...
BUG: unable to handle kernel paging request at ffff88013caee5c0
IP: [<ffffffff815604cf>] __alloc_skb+0x12f/0x1f0
...

Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
History 2015-03-24 08:22:18 -04:00
..
datagram.c net: treewide: Fix typo found in DocBook/networking.xml 2014-09-05 17:35:28 -07:00
dev.c net: reject creation of netdev names with colons 2015-03-14 15:37:12 -04:00
dev_addr_lists.c net: Add support for device specific address syncing 2014-06-02 10:40:54 -07:00
dev_ioctl.c dev_ioctl: remove dev_load() CAP_SYS_MODULE message 2014-09-05 12:04:40 -07:00
drop_monitor.c net: Replace get_cpu_var through this_cpu_ptr 2014-08-26 13:45:47 -04:00
dst.c ipv4: fix dst race in sk_dst_get() 2014-06-25 17:41:44 -07:00
ethtool.c net: ethtool: Return -EOPNOTSUPP if user space tries to read EEPROM with lengh 0 2014-10-31 16:12:34 -04:00
fib_rules.c net: fix 'ip rule' iif/oif device rename 2014-02-09 19:02:52 -08:00
filter.c net: filter: fix the comments 2014-10-10 15:11:51 -04:00
flow.c flowcache: Fix kernel panic in flow_cache_flush_task 2015-03-14 15:37:09 -04:00
flow_dissector.c flow-dissector: Fix alignment issue in __skb_flow_get_ports 2014-10-10 15:33:47 -04:00
gen_estimator.c net: sched: make bstats per cpu and estimator RCU safe 2014-09-30 01:02:26 -04:00
gen_stats.c gen_stats.c: Duplicate xstats buffer for later use 2015-03-14 15:37:10 -04:00
iovec.c net: sendmsg: fix NULL pointer dereference 2014-07-29 12:20:22 -07:00
link_watch.c arch: Mass conversion of smp_mb__*() 2014-04-18 14:20:48 +02:00
Makefile dmaengine-3.17 2014-10-07 20:39:25 -04:00
neighbour.c neighbour : fix ndm_type type error issue 2014-07-28 17:52:17 -07:00
net-procfs.c rps: selective flow shedding during softnet overflow 2013-05-20 13:48:04 -07:00
net-sysfs.c net: do not name the pointer to struct net_device net 2014-07-24 23:33:55 -07:00
net-sysfs.h net: netdev_kobject_init: annotate with __init 2014-01-05 20:27:54 -05:00
net-traces.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
net_namespace.c netns: remove one sparse warning 2014-09-09 20:10:45 -07:00
netclassid_cgroup.c cgroup: rename cgroup_subsys->base_cftypes to ->legacy_cftypes 2014-07-15 11:05:09 -04:00
netevent.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
netpoll.c net: Pass a "more" indication down into netdev_start_xmit() code paths. 2014-09-01 17:39:55 -07:00
netprio_cgroup.c cgroup: rename cgroup_subsys->base_cftypes to ->legacy_cftypes 2014-07-15 11:05:09 -04:00
pktgen.c net: pktgen: disable xmit_clone on virtual devices 2015-03-14 15:37:12 -04:00
ptp_classifier.c net: filter: split 'struct sk_filter' into socket and bpf parts 2014-08-02 15:03:58 -07:00
request_sock.c inet: reduce TLB pressure for listeners 2014-06-25 16:37:24 -07:00
rtnetlink.c net: do not use rcu in rtnl_dump_ifinfo() 2015-03-14 15:37:13 -04:00
scm.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2013-09-07 14:35:32 -07:00
secure_seq.c net: use ktime_get_ns() and ktime_get_real_ns() helpers 2014-08-22 19:57:23 -07:00
skbuff.c sock: sock_dequeue_err_skb() needs hard irq safety 2015-03-14 15:37:12 -04:00
sock.c net: Trap attempts to call sock_kfree_s() with a NULL pointer. 2014-10-14 17:02:37 -04:00
sock_diag.c net: filter: split 'struct sk_filter' into socket and bpf parts 2014-08-02 15:03:58 -07:00
stream.c net: replace macros net_random and net_srandom with direct calls to prandom 2014-01-14 15:15:25 -08:00
sysctl_net_core.c net: sysctl_net_core: check SNDBUF and RCVBUF for min length 2015-03-24 08:22:18 -04:00
timestamping.c net-timestamp: Make the clone operation stand-alone from phy timestamping 2014-09-05 17:43:45 -07:00
tso.c net: tso: fix unaligned access to crafted TCP header in helper API 2014-10-22 12:52:55 -04:00
utils.c net: optimise inet_proto_csum_replace4() 2014-09-26 16:14:17 -04:00