general cleanup of the API. The entire API now consists of two functions
similar to the pre-KSE API. The suser() function takes a thread pointer
as its only argument. The td_ucred member of this thread must be valid
so the only valid thread pointers are curthread and a few kernel threads
such as thread0. The suser_cred() function takes a pointer to a struct
ucred as its first argument and an integer flag as its second argument.
The flag is currently only used for the PRISON_ROOT flag.
Discussed on: smp@
Move the network code from using cr_cansee() to check whether a
socket is visible to a requesting credential to using a new
function, cr_canseesocket(), which accepts a subject credential
and object socket. Implement cr_canseesocket() so that it does a
prison check, a uid check, and add a comment where shortly a MAC
hook will go. This will allow MAC policies to seperately
instrument the visibility of sockets from the visibility of
processes.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
spares (the size of the field was changed from u_short to u_int to
reflect what it really ends up being). Accordingly, change users of
xucred to set and check this field as appropriate. In the kernel,
this is being done inside the new cru2x() routine which takes a
`struct ucred' and fills out a `struct xucred' according to the
former. This also has the pleasant sideaffect of removing some
duplicate code.
Reviewed by: rwatson
sysctl_req', which describes in-progress sysctl requests. This permits
sysctl handlers to have access to the current thread, permitting work
on implementing td->td_ucred, migration of suser() to using struct
thread to derive the appropriate ucred, and allowing struct thread to be
passed down to other code, such as network code where td is not currently
available (and curproc is used).
o Note: netncp and netsmb are not updated to reflect this change, as they
are not currently KSE-adapted.
Reviewed by: julian
Obtained from: TrustedBSD Project
a single kern.security.seeotheruids_permitted, describes as:
"Unprivileged processes may see subjects/objects with different real uid"
NOTE: kern.ps_showallprocs exists in -STABLE, and therefore there is
an API change. kern.ipc.showallsockets does not.
- Check kern.security.seeotheruids_permitted in cr_cansee().
- Replace visibility calls to socheckuid() with cr_cansee() (retain
the change to socheckuid() in ipfw, where it is used for rule-matching).
- Remove prison_unpcb() and make use of cr_cansee() against the UNIX
domain socket credential instead of comparing root vnodes for the
UDS and the process. This allows multiple jails to share the same
chroot() and not see each others UNIX domain sockets.
- Remove unused socheckproc().
Now that cr_cansee() is used universally for socket visibility, a variety
of policies are more consistently enforced, including uid-based
restrictions and jail-based restrictions. This also better-supports
the introduction of additional MAC models.
Reviewed by: ps, billf
Obtained from: TrustedBSD Project
kern.ipc.showallsockets is set to 0.
Submitted by: billf (with modifications by me)
Inspired by: Dave McKay (aka pm aka Packet Magnet)
Reviewed by: peter
MFC after: 2 weeks
In order to ensure security and functionality, RFC 1948 style
initial sequence number generation has been implemented. Barring
any major crypographic breakthroughs, this algorithm should be
unbreakable. In addition, the problems with TIME_WAIT recycling
which affect our currently used algorithm are not present.
Reviewed by: jesper
generation scheme. Users may now select between the currently used
OpenBSD algorithm and the older random positive increment method.
While the OpenBSD algorithm is more secure, it also breaks TIME_WAIT
handling; this is causing trouble for an increasing number of folks.
To switch between generation schemes, one sets the sysctl
net.inet.tcp.tcp_seq_genscheme. 0 = random positive increments,
1 = the OpenBSD algorithm. 1 is still the default.
Once a secure _and_ compatible algorithm is implemented, this sysctl
will be removed.
Reviewed by: jlemon
Tested by: numerous subscribers of -net
only do getcred calls for sockets which were created in the same jail.
This should allow the ident to work in a reasonable way within jails.
PR: 28107
Approved by: des, rwatson
connection. The information contained in a tcptemp can be
reconstructed from a tcpcb when needed.
Previously, tcp templates required the allocation of one
mbuf per connection. On large systems, this change should
free up a large number of mbufs.
Reviewed by: bmilekic, jlemon, ru
MFC after: 2 weeks
sizeof(ro_dst) is not necessarily the correct one.
this change would also fix the recent path MTU discovery problem for the
destination of an incoming TCP connection.
Submitted by: JINMEI Tatuya <jinmei@kame.net>
Obtained from: KAME
MFC after: 2 weeks
This work was based on kame-20010528-freebsd43-snap.tgz and some
critical problem after the snap was out were fixed.
There are many many changes since last KAME merge.
TODO:
- The definitions of SADB_* in sys/net/pfkeyv2.h are still different
from RFC2407/IANA assignment because of binary compatibility
issue. It should be fixed under 5-CURRENT.
- ip6po_m member of struct ip6_pktopts is no longer used. But, it
is still there because of binary compatibility issue. It should
be removed under 5-CURRENT.
Reviewed by: itojun
Obtained from: KAME
MFC after: 3 weeks
around, use a common function for looking up and extracting the tunables
from the kernel environment. This saves duplicating the same function
over and over again. This way typically has an overhead of 8 bytes + the
path string, versus about 26 bytes + the path string.
Change code from PRC_UNREACH_ADMIN_PROHIB to PRC_UNREACH_PORT for
ICMP_UNREACH_PROTOCOL and ICMP_UNREACH_PORT
And let TCP treat PRC_UNREACH_PORT like PRC_UNREACH_ADMIN_PROHIB
This should fix the case where port unreachables for udp returned
ENETRESET instead of ECONNREFUSED
Problem found by: Bill Fenner <fenner@research.att.com>
Reviewed by: jlemon
For TCP, verify that the sequence number in the ICMP packet falls within
the tcp receive window before performing any actions indicated by the
icmp packet.
Clean up some layering violations (access to tcp internals from in_pcb)
error will be passed up to the user, who will close the connection, so
it does not appear to make a sense to leave the connection open.
This also fixes a bug with kqueue, where the filter does not set EOF
on the connection, because the connection is still open.
Also remove calls to so{rw}wakeup, as we aren't doing anything with
them at the moment anyway.
Reviewed by: alfred, jesper
reset TCP connections which are in the SYN_SENT state, if the sequence
number in the echoed ICMP reply is correct. This behavior can be
controlled by the sysctl net.inet.tcp.icmp_may_rst.
Currently, only subtypes 2,3,10,11,12 are treated as such
(port, protocol and administrative unreachables).
Assocaiate an error code with these resets which is reported to the
user application: ENETRESET.
Disallow resetting TCP sessions which are not in a SYN_SENT state.
Reviewed by: jesper, -net
and 1.84 of src/sys/netinet/udp_usrreq.c
The changes broken down:
- remove 0 as a wildcard for addresses and port numbers in
src/sys/netinet/in_pcb.c:in_pcbnotify()
- add src/sys/netinet/in_pcb.c:in_pcbnotifyall() used to notify
all sessions with the specific remote address.
- change
- src/sys/netinet/udp_usrreq.c:udp_ctlinput()
- src/sys/netinet/tcp_subr.c:tcp_ctlinput()
to use in_pcbnotifyall() to notify multiple sessions, instead of
using in_pcbnotify() with 0 as src address and as port numbers.
- remove check for src port == 0 in
- src/sys/netinet/tcp_subr.c:tcp_ctlinput()
- src/sys/netinet/udp_usrreq.c:udp_ctlinput()
as they are no longer needed.
- move handling of redirects and host dead from in_pcbnotify() to
udp_ctlinput() and tcp_ctlinput(), so they will call
in_pcbnotifyall() to notify all sessions with the specific
remote address.
Approved by: jlemon
Inspired by: NetBSD
treat 0 as a wildcard in src/sys/in_pbc.c:in_pcbnotify()
It's sufficient to check for src|local port, as we'll have no
sessions with src|local port == 0
Without this a attacker sending ICMP messages, where the attached
IP header (+ 8 bytes) has the address and port numbers == 0, would
have the ICMP message applied to all sessions.
PR: kern/25195
Submitted by: originally by jesper, reimplimented by jlemon's advice
Reviewed by: jlemon
Approved by: jlemon
actually in the kernel. This structure is a different size than
what is currently in -CURRENT, but should hopefully be the last time
any application breakage is caused there. As soon as any major
inconveniences are removed, the definition of the in-kernel struct
ucred should be conditionalized upon defined(_KERNEL).
This also changes struct export_args to remove dependency on the
constantly-changing struct ucred, as well as limiting the bounds
of the size fields to the correct size. This means: a) mountd and
friends won't break all the time, b) mountd and friends won't crash
the kernel all the time if they don't know what they're doing wrt
actual struct export_args layout.
Reviewed by: bde
Add new PRC_UNREACH_ADMIN_PROHIB in sys/sys/protosw.h
Remove condition on TCP in src/sys/netinet/ip_icmp.c:icmp_input
In src/sys/netinet/ip_icmp.c:icmp_input set code = PRC_UNREACH_ADMIN_PROHIB
or PRC_UNREACH_HOST for all unreachables except ICMP_UNREACH_NEEDFRAG
Rename sysctl icmp_admin_prohib_like_rst to icmp_unreach_like_rst
to reflect the fact that we also react on ICMP unreachables that
are not administrative prohibited. Also update the comments to
reflect this.
In sys/netinet/tcp_subr.c:tcp_ctlinput add code to treat
PRC_UNREACH_ADMIN_PROHIB and PRC_UNREACH_HOST different.
PR: 23986
Submitted by: Jesper Skriver <jesper@skriver.dk>
messages send by routers when they deny our traffic, this causes
a timeout when trying to connect to TCP ports/services on a remote
host, which is blocked by routers or firewalls.
rfc1122 (Requirements for Internet Hosts) section 3.2.2.1 actually
requi re that we treat such a message for a TCP session, that we
treat it like if we had recieved a RST.
quote begin.
A Destination Unreachable message that is received MUST be
reported to the transport layer. The transport layer SHOULD
use the information appropriately; for example, see Sections
4.1.3.3, 4.2.3.9, and 4.2.4 below. A transport protocol
that has its own mechanism for notifying the sender that a
port is unreachable (e.g., TCP, which sends RST segments)
MUST nevertheless accept an ICMP Port Unreachable for the
same purpose.
quote end.
I've written a small extension that implement this, it also create
a sysctl "net.inet.tcp.icmp_admin_prohib_like_rst" to control if
this new behaviour is activated.
When it's activated (set to 1) we'll treat a ICMP administratively
prohibited message (icmp type 3 code 9, 10 and 13) for a TCP
sessions, as if we recived a TCP RST, but only if the TCP session
is in SYN_SENT state.
The reason for only reacting when in SYN_SENT state, is that this
will solve the problem, and at the same time minimize the risk of
this being abused.
I suggest that we enable this new behaviour by default, but it
would be a change of current behaviour, so if people prefer to
leave it disabled by default, at least for now, this would be ok
for me, the attached diff actually have the sysctl set to 0 by
default.
PR: 23086
Submitted by: Jesper Skriver <jesper@skriver.dk>
because it only takes a struct tag which makes it impossible to
use unions, typedefs etc.
Define __offsetof() in <machine/ansi.h>
Define offsetof() in terms of __offsetof() in <stddef.h> and <sys/types.h>
Remove myriad of local offsetof() definitions.
Remove includes of <stddef.h> in kernel code.
NB: Kernelcode should *never* include from /usr/include !
Make <sys/queue.h> include <machine/ansi.h> to avoid polluting the API.
Deprecate <struct.h> with a warning. The warning turns into an error on
01-12-2000 and the file gets removed entirely on 01-01-2001.
Paritials reviews by: various.
Significant brucifications by: bde
delete the cloned route that is associated with the connection.
This does not exhaust the routing table memory when the system
is under a SYN flood attack. The route entry is not deleted if there
is any prior information cached in it.
Reviewed by: Peter Wemm,asmodai
