linux/include
Daniel Borkmann 38ab1fa981 net: sctp: fix ABI mismatch through sctp_assoc_to_state helper
Since SCTP day 1, that is, 19b55a2af145 ("Initial commit") from lksctp
tree, the official <netinet/sctp.h> header carries a copy of enum
sctp_sstat_state that looks like (compared to the current in-kernel
enumeration):

  User definition:                     Kernel definition:

  enum sctp_sstat_state {              typedef enum {
    SCTP_EMPTY             = 0,          <removed>
    SCTP_CLOSED            = 1,          SCTP_STATE_CLOSED            = 0,
    SCTP_COOKIE_WAIT       = 2,          SCTP_STATE_COOKIE_WAIT       = 1,
    SCTP_COOKIE_ECHOED     = 3,          SCTP_STATE_COOKIE_ECHOED     = 2,
    SCTP_ESTABLISHED       = 4,          SCTP_STATE_ESTABLISHED       = 3,
    SCTP_SHUTDOWN_PENDING  = 5,          SCTP_STATE_SHUTDOWN_PENDING  = 4,
    SCTP_SHUTDOWN_SENT     = 6,          SCTP_STATE_SHUTDOWN_SENT     = 5,
    SCTP_SHUTDOWN_RECEIVED = 7,          SCTP_STATE_SHUTDOWN_RECEIVED = 6,
    SCTP_SHUTDOWN_ACK_SENT = 8,          SCTP_STATE_SHUTDOWN_ACK_SENT = 7,
  };                                   } sctp_state_t;

This header was later on also placed into the uapi, so that user space
programs can compile without having <netinet/sctp.h>, but the shipped
with <linux/sctp.h> instead.

While RFC6458 under 8.2.1.Association Status (SCTP_STATUS) says that
sstat_state can range from SCTP_CLOSED to SCTP_SHUTDOWN_ACK_SENT, we
nevertheless have a what it appears to be dummy SCTP_EMPTY state from
the very early days.

While it seems to do just nothing, commit 0b8f9e25b0 ("sctp: remove
completely unsed EMPTY state") did the right thing and removed this dead
code. That however, causes an off-by-one when the user asks the SCTP
stack via SCTP_STATUS API and checks for the current socket state thus
yielding possibly undefined behaviour in applications as they expect
the kernel to tell the right thing.

The enumeration had to be changed however as based on the current socket
state, we access a function pointer lookup-table through this. Therefore,
I think the best way to deal with this is just to add a helper function
sctp_assoc_to_state() to encapsulate the off-by-one quirk.

Reported-by: Tristan Su <sooqing@gmail.com>
Fixes: 0b8f9e25b0 ("sctp: remove completely unsed EMPTY state")
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-29 20:31:08 -07:00
..
acpi ACPI and power management updates for 3.17-rc1 2014-08-06 20:34:19 -07:00
asm-generic This is the bulk of GPIO changes for the v3.17 development 2014-08-08 18:00:35 -07:00
clocksource ARM: pxa: Add non device-tree timer link to clocksource 2014-07-23 12:02:39 +02:00
crypto Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2014-08-06 08:06:39 -07:00
drm Merge branch 'linux-3.17' of git://anongit.freedesktop.org/git/nouveau/linux-2.6 2014-08-09 17:46:39 -07:00
dt-bindings Merge branch 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma 2014-08-11 07:14:01 -07:00
keys Merge remote-tracking branch 'integrity/next-with-keys' into keys-next 2014-07-22 21:54:43 +01:00
kvm KVM: ARM: vgic: add the GICv3 backend 2014-07-11 04:57:36 -07:00
linux net/mlx4: Move the tunnel steering helper function to mlx4_core 2014-08-29 20:13:00 -07:00
math-emu
media [media] media: atmel-isi: add v4l2 async probe support 2014-07-30 19:35:06 -03:00
memory
misc
net net: sctp: fix ABI mismatch through sctp_assoc_to_state helper 2014-08-29 20:31:08 -07:00
pcmcia
ras
rdma Merge branches 'core', 'cxgb4', 'ipoib', 'iser', 'iwcm', 'mad', 'misc', 'mlx4', 'mlx5', 'ocrdma' and 'srp' into for-next 2014-08-14 08:58:04 -07:00
rxrpc
scsi SCSI misc on 20140815 2014-08-15 18:28:58 -06:00
soc/tegra ARM: tegra: Convert PMC to a driver 2014-07-17 14:58:43 +02:00
sound ASoC: Updates for v3.17 2014-08-04 18:28:21 +02:00
target
trace Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2014-08-14 10:14:07 -06:00
uapi asm-generic: add memfd_create system call to unistd.h 2014-08-18 19:47:04 +01:00
video fbdev changes for 3.17 2014-08-08 18:09:33 -07:00
xen - Remove unused V2 grant table support. 2014-08-07 11:33:15 -07:00
Kbuild