linux_dsm_epyc7002/net/core
Matthew Dawson a0917e0bc6 datagram: When peeking datagrams with offset < 0 don't skip empty skbs
Due to commit e6afc8ace6 ("udp: remove
headers from UDP packets before queueing"), when udp packets are being
peeked the requested extra offset is always 0 as there is no need to skip
the udp header.  However, when the offset is 0 and the next skb is
of length 0, it is only returned once.  The behaviour can be seen with
the following python script:

from socket import *;
f=socket(AF_INET6, SOCK_DGRAM | SOCK_NONBLOCK, 0);
g=socket(AF_INET6, SOCK_DGRAM | SOCK_NONBLOCK, 0);
f.bind(('::', 0));
addr=('::1', f.getsockname()[1]);
g.sendto(b'', addr)
g.sendto(b'b', addr)
print(f.recvfrom(10, MSG_PEEK));
print(f.recvfrom(10, MSG_PEEK));

Where the expected output should be the empty string twice.

Instead, make sk_peek_offset return negative values, and pass those values
to __skb_try_recv_datagram/__skb_try_recv_from_queue.  If the passed offset
to __skb_try_recv_from_queue is negative, the checked skb is never skipped.
__skb_try_recv_from_queue will then ensure the offset is reset back to 0
if a peek is requested without an offset, unless no packets are found.

Also simplify the if condition in __skb_try_recv_from_queue.  If _off is
greater then 0, and off is greater then or equal to skb->len, then
(_off || skb->len) must always be true assuming skb->len >= 0 is always
true.

Also remove a redundant check around a call to sk_peek_offset in af_unix.c,
as it double checked if MSG_PEEK was set in the flags.

V2:
 - Moved the negative fixup into __skb_try_recv_from_queue, and remove now
redundant checks
 - Fix peeking in udp{,v6}_recvmsg to report the right value when the
offset is 0

V3:
 - Marked new branch in __skb_try_recv_from_queue as unlikely.

Signed-off-by: Matthew Dawson <matthew@mjdsystems.ca>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-18 15:12:54 -07:00
..
datagram.c datagram: When peeking datagrams with offset < 0 don't skip empty skbs 2017-08-18 15:12:54 -07:00
dev_addr_lists.c net: fix spelling for synchronized 2014-11-18 15:26:32 -05:00
dev_ioctl.c net: check dev->addr_len for dev_set_mac_address() 2017-07-29 11:25:05 -07:00
dev.c net: avoid skb_warn_bad_offload false positives on UFO 2017-08-08 21:39:01 -07:00
devlink.c devlink: fix potential memort leak 2017-06-05 11:24:28 -04:00
drop_monitor.c drop_monitor: use setup_timer 2017-03-12 23:47:16 -07:00
dst_cache.c net: dst_cache_per_cpu_dst_set() can be static 2016-03-18 17:45:08 -04:00
dst.c net: store port/representator id in metadata_dst 2017-06-25 11:42:01 -04:00
ethtool.c ethtool: don't open-code memdup_user() 2017-06-30 02:04:10 -04:00
fib_rules.c net: set fib rule refcount after malloc 2017-07-13 13:43:54 -07:00
filter.c bpf: fix two missing target_size settings in bpf_convert_ctx_access 2017-08-11 14:59:24 -07:00
flow_dissector.c net/flow_dissector: add support for dissection of misc ip header fields 2017-06-04 18:12:23 -04:00
flow.c flowcache: more "unsigned int" 2017-04-03 19:04:48 -07:00
gen_estimator.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
gen_stats.c net_sched: gen_estimator: complete rewrite of rate estimators 2016-12-05 15:21:59 -05:00
gro_cells.c net: Generic XDP 2017-04-25 13:33:49 -04:00
hwbm.c net: hwbm: Fix unbalanced spinlock in error case 2016-05-25 12:35:09 -07:00
link_watch.c dev: introduce dev_get_iflink() 2015-04-02 14:04:59 -04:00
lwt_bpf.c net: add extack arg to lwtunnel build state 2017-05-30 11:55:32 -04:00
lwtunnel.c net: add extack arg to lwtunnel build state 2017-05-30 11:55:32 -04:00
Makefile gro_cells: move to net/core/gro_cells.c 2017-02-08 14:38:18 -05:00
neighbour.c Add wait_for_random_bytes() and get_random_*_wait() functions so that 2017-07-15 12:44:02 -07:00
net_namespace.c net: convert net.passive from atomic_t to refcount_t 2017-07-01 07:39:09 -07:00
net-procfs.c net-procfs: Use vsnprintf extension %phN 2017-06-04 19:52:58 -04:00
net-sysfs.c net: convert net.passive from atomic_t to refcount_t 2017-07-01 07:39:09 -07:00
net-sysfs.h net: netdev_kobject_init: annotate with __init 2014-01-05 20:27:54 -05:00
net-traces.c net: IPv6 fib lookup tracepoint 2015-11-22 11:54:10 -05:00
netclassid_cgroup.c cgroup, net_cls: iterate the fds of only the tasks which are being migrated 2017-03-22 10:32:46 -07:00
netevent.c netevent: remove automatic variable in register_netevent_notifier() 2015-05-31 00:03:21 -07:00
netpoll.c netpoll: Fix device name check in netpoll_setup() 2017-07-26 17:01:43 -07:00
netprio_cgroup.c net: break include loop netdevice.h, dsa.h, devlink.h 2017-03-28 22:46:04 -07:00
pktgen.c net: convert sk_buff.users from atomic_t to refcount_t 2017-07-01 07:39:07 -07:00
ptp_classifier.c ptp: Change ptp_class to a proper bitmask 2015-11-03 11:08:22 -05:00
request_sock.c ipv4: Namespaceify tcp_max_syn_backlog knob 2016-12-29 11:38:31 -05:00
rtnetlink.c rtnetlink: allocate more memory for dev_set_mac_address() 2017-07-20 15:23:22 -07:00
scm.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/user.h> 2017-03-02 08:42:29 +01:00
secure_seq.c tcp: Namespaceify sysctl_tcp_timestamps 2017-06-08 10:53:29 -04:00
skbuff.c mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic 2017-07-12 16:26:03 -07:00
sock_diag.c netlink: extended ACK reporting 2017-04-13 13:58:20 -04:00
sock_reuseport.c soreuseport: use "unsigned int" in __reuseport_alloc() 2017-04-03 19:06:38 -07:00
sock.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-07-05 12:31:59 -07:00
stream.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h> 2017-03-02 08:42:29 +01:00
sysctl_net_core.c net: move somaxconn init from sysctl code 2017-05-25 13:12:17 -04:00
timestamping.c net: skb_defer_rx_timestamp should check for phydev before setting up classify 2015-07-09 14:17:15 -07:00
tso.c net: tso: add support for IPv6 2015-10-26 22:24:22 -07:00
utils.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-05-02 16:40:27 -07:00