netfilter: nf_conntrack_h323: Add protection for bmp length out of range

UBSAN load reports an exception of BRK#5515 SHIFT_ISSUE:Bitwise shifts
that are out of bounds for their data type.

vmlinux get_bitmap(b=75) + 712
<net/netfilter/nf_conntrack_h323_asn1.c:0>
vmlinux decode_seq(bs=0xFFFFFFD008037000, f=0xFFFFFFD008037018, level=134443100) + 1956
<net/netfilter/nf_conntrack_h323_asn1.c:592>
vmlinux decode_choice(base=0xFFFFFFD0080370F0, level=23843636) + 1216
<net/netfilter/nf_conntrack_h323_asn1.c:814>
vmlinux decode_seq(f=0xFFFFFFD0080371A8, level=134443500) + 812
<net/netfilter/nf_conntrack_h323_asn1.c:576>
vmlinux decode_choice(base=0xFFFFFFD008037280, level=0) + 1216
<net/netfilter/nf_conntrack_h323_asn1.c:814>
vmlinux DecodeRasMessage() + 304
<net/netfilter/nf_conntrack_h323_asn1.c:833>
vmlinux ras_help() + 684
<net/netfilter/nf_conntrack_h323_main.c:1728>
vmlinux nf_confirm() + 188
<net/netfilter/nf_conntrack_proto.c:137>

Due to abnormal data in skb->data, the extension bitmap length
exceeds 32 when decoding ras message then uses the length to make
a shift operation. It will change into negative after several loop.
UBSAN load could detect a negative shift as an undefined behaviour
and reports exception.
So we add the protection to avoid the length exceeding 32. Or else
it will return out of range error and stop decoding.

Fixes: 5e35941d9901 ("[NETFILTER]: Add H.323 conntrack/NAT helper")
Signed-off-by: Lena Wang <lena.wang@mediatek.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: Update obsolete comments referring to ip_conntrack

In 9fb9cbb1082d ("[NETFILTER]: Add nf_conntrack subsystem.") the new
generic nf_conntrack was introduced, and it came to supersede the old
ip_conntrack.

This change updates (some) of the obsolete comments referring to old
file/function names of the ip_conntrack mechanism, as well as removes a
few self-referencing comments that we shouldn't maintain anymore.

I did not update any comments referring to historical actions (e.g,
comments like "this file was derived from ..." were left untouched, even
if the referenced file is no longer here).

Signed-off-by: Yonatan Goldschmidt <yon.goldschmidt@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230

Based on 2 normalized pattern(s):

this source code is licensed under the gnu general public license
version 2 see the file copying for more details

this source code is licensed under general public license version 2
see

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 52 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.449021192@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

netfilter: nf_conntrack_h323: restore boundary check correctness

Since commit bc7d811ace4a ("netfilter: nf_ct_h323: Convert
CHECK_BOUND macro to function"), NAT traversal for H.323
doesn't work, failing to parse H323-UserInformation.
nf_h323_error_boundary() compares contents of the bitstring,
not the addresses, preventing valid H.323 packets from being
conntrack'd.

This looks like an oversight from when CHECK_BOUND macro was
converted to a function.

To fix it, stop dereferencing bs->cur and bs->end.

Fixes: bc7d811ace4a ("netfilter: nf_ct_h323: Convert CHECK_BOUND macro to function")
Signed-off-by: Jakub Jankowski <shasta@toxcorp.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_conntrack_h323: Remove unwanted comments.

Change old multi-line comment style to kernel comment style and
remove unwanted comments.

Signed-off-by: Varsha Rao <rvarsha016@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: mark expected switch fall-throughs

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_ct_h323: Extend nf_h323_error_boundary to work on bits as well

This patch fixes several out of bounds memory reads by extending
the nf_h323_error_boundary() function to work on bits as well
an check the affected parts.

Signed-off-by: Eric Sesterhenn <eric.sesterhenn@x41-dsec.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_ct_h323: Convert CHECK_BOUND macro to function

It is bad practive to return in a macro, this patch
moves the check into a function.

Signed-off-by: Eric Sesterhenn <eric.sesterhenn@x41-dsec.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_ct_h323: Out Of Bound Read in Netfilter Conntrack

Add missing counter decrement to prevent out of bounds memory read.

Signed-off-by: Eric Sesterhenn <eric.sesterhenn@x41-dsec.de>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_conntrack_h323: Remove typedef struct

Remove typedef from struct as linux-kernel coding style tends to
avoid using typedefs.
Done using following coccinelle semantic patch

@r1@
type T;
@@

typedef struct { ... } T;

@script:python c1@
T2;
T << r1.T;
@@
if T[-2:] =="_t" or T[-2:] == "_T":
coccinelle.T2 = T[:-2];
else:
coccinelle.T2 = T;

print T, coccinelle.T2

@r2@
type r1.T;
identifier c1.T2;
@@
-typedef
struct
+ T2
{ ... }
-T
;

@r3@
type r1.T;
identifier c1.T2;
@@
-T
+struct T2

Signed-off-by: Harsha Sharma <harshasharmaiitr@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_conntrack_h323: fix off-by-one in DecodeQ931

This patch corrects an off-by-one error in the DecodeQ931 function in
the nf_conntrack_h323 module. This error could result in reading off
the end of a Q.931 frame.

Signed-off-by: Toby DiPasquale <toby@cbcg.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: h323: bug in parsing of ASN1 SEQOF field

Static analyzer of clang found a dead store which appears to be a bug in
reading count of items in SEQOF field, only the lower byte of word is
stored. This may lead to corrupted read and communication shutdown.

The bug has been in the module since it's first inclusion into linux
kernel.

[Patrick: the bug is real, but without practical consequence since the
largest amount of sequence-of members we parse is 30.]

Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Patrick McHardy <kaber@trash.net>

[NETFILTER]: nf_conntrack_h323: constify and annotate H.323 helper

Constify data tables (predominantly in nf_conntrack_h323_types.c, but
also a few in nf_conntrack_h323_asn1.c) and use const qualifiers on
variables where possible in the h323 sources.

Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: nf_conntrack_h323: clean up code a bit

-total: 81 errors, 3 warnings, 876 lines checked
+total: 44 errors, 3 warnings, 876 lines checked

There is still work to be done, but that's for another patch.

Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: nf_conntrack_h3223: sparse fixes

Sparse complains when a function is not really static. Putting static
on the function prototype is not enough.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: Parenthesize macro parameters

Parenthesize macro parameters.

Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: nf_conntrack_h323: check range first in sequence extension

Check range before checking STOP flag. This optimization may save a
nanosecond or less :)

Signed-off-by: Jing Min Zhao <zhaojingmin@vivecode.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: nf_conntrack_h323: add checking of out-of-range on choices' index values

Choices' index values may be out of range while still encoded in the fixed
length bit-field. This bug may cause access to undefined types (NULL
pointers) and thus crashes (Reported by Zhongling Wen).

This patch also adds checking of decode flag when decoding SEQUENCEs.

Signed-off-by: Jing Min Zhao <zhaojingmin@vivecode.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: nf_conntrack/nf_nat: add H.323 helper port

Add IPv4 and IPv6 capable nf_conntrack port of the H.323 conntrack/NAT helper.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>