Remove a number of instances that do not match common patterns and have
the only substantial effect on the code flow that a truncated packet
triggers "goto trunc" instead of longjmp(). (In a few cases this change
can increase the number of fields printed before giving up.)
ND_TCHECK_n(e), n in { 1, 2, 3, 4, 8 }.
They are redundant because they are followed by a GET_.*_n(e) call,
same n, same e, which do the bounds check.
Remove unused 'trunc' labels and most associated codes.
Update the outputs of some tests accordingly.
Replace more calls to ipaddr_string()/ip6addr_string() with calls to
GET_IPADDR_STRING()/GET_IP6ADDR_STRING() macros performing bounds
checking.
Add similar bounds-checking inline functions and macros to wrap
linkaddr_string(), etheraddr_string(), and isonsap_string() and convert
calls to them to use the macros as well.
Shuffle the inline functions in addrtoname.h around a bit, so that the
inline functions, external declarations, and macros are all in the same
order.
Check that the payload specified in a Jumbo Payload option isn't smaller
than the total number of bytes worth of extension headers; if it is,
report truncation.
Check that:
1) we don't have more than one Jumbo Payload option;
2) we don't have a Jumbo Payload option if the payload length in the
IPv6 header was non-zero;
3) we don't have a Jumbo Payload option with a value < 65536.
If we see one when processing the hop-by-hop extension header, use it to
set the payload length.
In UDP, if we have a zero length field in the UDP header, and the length
of the data handed to us is > 65535, treat that as a Jumbo Payload
packet.
If we have an Ethernet packet where the last 2 octets of the header are
a length rather than an Ethernet type, and it's less than the remaining
length of the packet, shorten the length and captured length, update the
snapshot end.
Turn the buffer stack into a "packet information" stack, so that, if we
*do* update the snapshot end, we push the old end onto the stack, and
pop it off as soon as we're done dissecting the Ethernet packet, in case
there's more data in the packet after the Ethernet packet.
Use the stack when we use the IPv4 and IPv6 length fields as well.
The checksum calculation for IPv6 packets is based on a pseudo
header that includes the packet's final Destination Address (DA).
If the IPv6 packet contains a Routing header, the final DA is the
last element of the Routing header [RFC8200].
Currently, tcpdump supports Routing header types 0 and 2.
IPv6 Segment Routing Header (SRH) is a new Routing header type (4).
SRH is defined in draft-ietf-6man-segment-routing-header [1].
This patch fix the checksum calculation for SRv6 packets. It allows
tcpdump to get the final DA value from SRv6 packets.
[1] https://tools.ietf.org/html/draft-ietf-6man-segment-routing-header-17
That means less duplication of functionality - and less chance that
XXX-over-IPv4 will be handled but XXX-over-IPv6 won't be handled, or
*vice versa*. (CARP and VRRP were being handled over IPv4 but not over
IPv6; this fixes that.)
The exceptions are currently:
Some EXTRACT_ in print-juniper.c, not used on packet buffer pointer.
An EXTRACT_BE_U_3 in addrtoname.c, not always used on packet buffer
pointer.
This can prevent bizarre failures if, for example, you've done a
configuration in the top-level source directory, leaving behind one
config.h file, and then do an out-of-tree build in another directory,
with different configuration options. This way, we always pick up the
same config.h, in the build directory.
Now all the macros have a name meaning a count in bytes.
With _S_: signed, _U_: unsigned
e.g.:
EXTRACT_BE_32BITS -> EXTRACT_BE_U_4
EXTRACT_LE_32BITS -> EXTRACT_LE_U_4
...
EXTRACT_BE_INT32 -> EXTRACT_BE_S_4
and have:
EXTRACT_8BITS -> EXTRACT_U_1
EXTRACT_INT8 -> EXTRACT_S_1
Get rid of casts to (int) that aren't needed or wanted.
If a field is unsigned, use an unsigned variable for it, print it with
%u, not %d, and don't cast it to int.
Replace a static variable in print-dvmrp.c with a local variable in
dvmrp_print() and a parameter to print_neighbors2().
The EIGRP protocol can be carried in IPv4 or IPv6. The basic protocol
remains the same. So call the EIGRP dissector for IPv6 packets with
IPPROTO_EIGRP.
rt6_print(), ah_print(), and esp_print() return -1 if they run up
against the end of the packet while dissecting; if that happens, stop
dissecting, don't try to fetch the next header value, because 1) *it*
might be past the end of the packet and 2) we won't be using it in any
case, as we'll be exiting the loop.
Also, change mobility_print() to return -1 if it runs up against the
end of the packet, and stop dissecting if it does so.
This fixes a buffer over-read discovered by Brian 'geeknik' Carpenter.
Add tests using the capture files supplied by the reporter(s).
Make dst_addr a "const void *" to squelch
taking address of packed member 'ip6_dst' of class or structure
'ip6_hdr' may result in an unaligned pointer value
[-Waddress-of-packed-member]
warnings from some versions of Clang.
Add a few checks to ip6_print() to make it stop decoding the IPv6
headers immediately when the header-specific functions signal an error
condition. Without this it tried to fetch the next header selector for
the next round regardless and could run outside of the allocated packet
space on a specially crafted IPv6 packet.
Brian Carpenter has demonstrated this for the Hop-by-Hop Options header.
Fix that specific case and also the Destination Options and Fragment
header processing as those use the same logic.
with the tag '\summary:' for greping.
Remark: Currently some printers have no summary line.
Moreover:
Summarize all printers with a single line in INSTALL.txt
If we have a routing header, instead of overwriting the packet's IPv6
destination address in the packet with the final destination, so that
the next protocol's checksum routine can use it, we do as we do for
IPv4, and, in the "next protocol checksum" routine, scan the headers
looking for a routing header and, if we find one, copy the final
destination from it.
While we're at it, clean up a few things.
Have our own routines to convert between IPv4/IPv6 addresses and
strings; that helps if, for example, we want to build binary versions of
tcpdump for Windows that can run both on NT 5 (W2K/WXP), which doesn't
have inet_ntop() or inet_pton(), and NT 6 (Vista/7/8/10), which do. It
also means that we don't require IPv6 library support on UN*X to print
addresses (if somebody wants to build tcpdump for older UN*Xes lacking
IPv6 support in the system library or in add-on libraries).
Get rid of files in the missing directory that we don't need, and
various no-longer-necessary autoconf tests.
The checksum only covers the header, not the encapsulated packet, so
only checksum that. However, if that checksum fails, try checksumming
the entire packet, as, according to RFC 4601, packets with the entire
packet checksummed should also be accepted, for interoperability.
The purpose of this macro was to enable the file-by-file switch to NDO,
after which only tcpdump.c had a use of it and the definitions guarded
by it. Update tcpdump.c not to require them any more and dismiss the
unused definitions.
Always define and declare ip6_print(), always compile print-ip6.c, and
always call it if we recognize a payload as IPv6. If INET6 isn't
defined, ip6_print() will just print the length and note that printing
isn't supported.
That way, we don't do weird dissection of IPv6 packets on systems
without IPv6 support, due to, for example, ethertype_print() returning 0
("not dissected") for IPv6 packets on those systems (IPv6-over-Frame
Relay was dissected weirdly due to this).
And, as we require at least autoconf 2.61, and as autoconf 2.61 and
later have AC_TYPE_UINTn_T and AC_TYPE_INTn_T macros, we use them to
define the uintN_t and intN_t macros if the system doesn't define them
for us.
This lets us get rid of bitypes.h as well.
