Skip to content

K
Kernel

openeuler / Kernel
大约 1 年 前同步成功

通知 6
Star 0
Fork 0
K
Kernel

体验新版 GitCode，发现更多精彩内容 >>

切换分支/标签
  1. 21 3月, 2006 1 次提交
    • C
      [SECURITY]: TCP/UDP getpeersec · 2c7946a7
      由 Catherine Zhang 提交于 
      This patch implements an application of the LSM-IPSec networking
controls whereby an application can determine the label of the
security association its TCP or UDP sockets are currently connected to
via getsockopt and the auxiliary data mechanism of recvmsg.

Patch purpose:

This patch enables a security-aware application to retrieve the
security context of an IPSec security association a particular TCP or
UDP socket is using.  The application can then use this security
context to determine the security context for processing on behalf of
the peer at the other end of this connection.  In the case of UDP, the
security context is for each individual packet.  An example
application is the inetd daemon, which could be modified to start
daemons running at security contexts dependent on the remote client.

Patch design approach:

- Design for TCP
The patch enables the SELinux LSM to set the peer security context for
a socket based on the security context of the IPSec security
association.  The application may retrieve this context using
getsockopt.  When called, the kernel determines if the socket is a
connected (TCP_ESTABLISHED) TCP socket and, if so, uses the dst_entry
cache on the socket to retrieve the security associations.  If a
security association has a security context, the context string is
returned, as for UNIX domain sockets.

- Design for UDP
Unlike TCP, UDP is connectionless.  This requires a somewhat different
API to retrieve the peer security context.  With TCP, the peer
security context stays the same throughout the connection, thus it can
be retrieved at any time between when the connection is established
and when it is torn down.  With UDP, each read/write can have
different peer and thus the security context might change every time.
As a result the security context retrieval must be done TOGETHER with
the packet retrieval.

The solution is to build upon the existing Unix domain socket API for
retrieving user credentials.  Linux offers the API for obtaining user
credentials via ancillary messages (i.e., out of band/control messages
that are bundled together with a normal message).

Patch implementation details:

- Implementation for TCP
The security context can be retrieved by applications using getsockopt
with the existing SO_PEERSEC flag.  As an example (ignoring error
checking):

getsockopt(sockfd, SOL_SOCKET, SO_PEERSEC, optbuf, &optlen);
printf("Socket peer context is: %s\n", optbuf);

The SELinux function, selinux_socket_getpeersec, is extended to check
for labeled security associations for connected (TCP_ESTABLISHED ==
sk->sk_state) TCP sockets only.  If so, the socket has a dst_cache of
struct dst_entry values that may refer to security associations.  If
these have security associations with security contexts, the security
context is returned.

getsockopt returns a buffer that contains a security context string or
the buffer is unmodified.

- Implementation for UDP
To retrieve the security context, the application first indicates to
the kernel such desire by setting the IP_PASSSEC option via
getsockopt.  Then the application retrieves the security context using
the auxiliary data mechanism.

An example server application for UDP should look like this:

toggle = 1;
toggle_len = sizeof(toggle);

setsockopt(sockfd, SOL_IP, IP_PASSSEC, &toggle, &toggle_len);
recvmsg(sockfd, &msg_hdr, 0);
if (msg_hdr.msg_controllen > sizeof(struct cmsghdr)) {
    cmsg_hdr = CMSG_FIRSTHDR(&msg_hdr);
    if (cmsg_hdr->cmsg_len <= CMSG_LEN(sizeof(scontext)) &&
        cmsg_hdr->cmsg_level == SOL_IP &&
        cmsg_hdr->cmsg_type == SCM_SECURITY) {
        memcpy(&scontext, CMSG_DATA(cmsg_hdr), sizeof(scontext));
    }
}

ip_setsockopt is enhanced with a new socket option IP_PASSSEC to allow
a server socket to receive security context of the peer.  A new
ancillary message type SCM_SECURITY.

When the packet is received we get the security context from the
sec_path pointer which is contained in the sk_buff, and copy it to the
ancillary message space.  An additional LSM hook,
selinux_socket_getpeersec_udp, is defined to retrieve the security
context from the SELinux space.  The existing function,
selinux_socket_getpeersec does not suit our purpose, because the
security context is copied directly to user space, rather than to
kernel space.

Testing:

We have tested the patch by setting up TCP and UDP connections between
applications on two machines using the IPSec policies that result in
labeled security associations being built.  For TCP, we can then
extract the peer security context using getsockopt on either end.  For
UDP, the receiving end can retrieve the security context using the
auxiliary data mechanism of recvmsg.
Signed-off-by: NCatherine Zhang <cxzhang@watson.ibm.com>
Acked-by: NJames Morris <jmorris@namei.org>
Acked-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      2c7946a7
  3. 12 3月, 2006 1 次提交
  5. 06 2月, 2006 1 次提交
  7. 02 2月, 2006 3 次提交
  9. 15 1月, 2006 1 次提交
  11. 09 1月, 2006 1 次提交
  13. 04 1月, 2006 1 次提交
    • T
      [LSM-IPSec]: Per-packet access control. · d28d1e08
      由 Trent Jaeger 提交于 
      This patch series implements per packet access control via the
extension of the Linux Security Modules (LSM) interface by hooks in
the XFRM and pfkey subsystems that leverage IPSec security
associations to label packets.  Extensions to the SELinux LSM are
included that leverage the patch for this purpose.

This patch implements the changes necessary to the SELinux LSM to
create, deallocate, and use security contexts for policies
(xfrm_policy) and security associations (xfrm_state) that enable
control of a socket's ability to send and receive packets.

Patch purpose:

The patch is designed to enable the SELinux LSM to implement access
control on individual packets based on the strongly authenticated
IPSec security association.  Such access controls augment the existing
ones in SELinux based on network interface and IP address.  The former
are very coarse-grained, and the latter can be spoofed.  By using
IPSec, the SELinux can control access to remote hosts based on
cryptographic keys generated using the IPSec mechanism.  This enables
access control on a per-machine basis or per-application if the remote
machine is running the same mechanism and trusted to enforce the
access control policy.

Patch design approach:

The patch's main function is to authorize a socket's access to a IPSec
policy based on their security contexts.  Since the communication is
implemented by a security association, the patch ensures that the
security association's negotiated and used have the same security
context.  The patch enables allocation and deallocation of such
security contexts for policies and security associations.  It also
enables copying of the security context when policies are cloned.
Lastly, the patch ensures that packets that are sent without using a
IPSec security assocation with a security context are allowed to be
sent in that manner.

A presentation available at
www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf
from the SELinux symposium describes the overall approach.

Patch implementation details:

The function which authorizes a socket to perform a requested
operation (send/receive) on a IPSec policy (xfrm_policy) is
selinux_xfrm_policy_lookup.  The Netfilter and rcv_skb hooks ensure
that if a IPSec SA with a securit y association has not been used,
then the socket is allowed to send or receive the packet,
respectively.

The patch implements SELinux function for allocating security contexts
when policies (xfrm_policy) are created via the pfkey or xfrm_user
interfaces via selinux_xfrm_policy_alloc.  When a security association
is built, SELinux allocates the security context designated by the
XFRM subsystem which is based on that of the authorized policy via
selinux_xfrm_state_alloc.

When a xfrm_policy is cloned, the security context of that policy, if
any, is copied to the clone via selinux_xfrm_policy_clone.

When a xfrm_policy or xfrm_state is freed, its security context, if
any is also freed at selinux_xfrm_policy_free or
selinux_xfrm_state_free.

Testing:

The SELinux authorization function is tested using ipsec-tools.  We
created policies and security associations with particular security
contexts and added SELinux access control policy entries to verify the
authorization decision.  We also made sure that packets for which no
security context was supplied (which either did or did not use
security associations) were authorized using an unlabelled context.
Signed-off-by: NTrent Jaeger <tjaeger@cse.psu.edu>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      d28d1e08
  15. 09 11月, 2005 1 次提交
  17. 31 10月, 2005 6 次提交
  19. 28 10月, 2005 1 次提交
  21. 01 10月, 2005 1 次提交
    • J
      [PATCH] SELinux - fix SCTP socket bug and general IP protocol handling · 13402580
      由 James Morris 提交于 
      The following patch updates the way SELinux classifies and handles IP
based protocols.

Currently, IP sockets are classified by SELinux as being either TCP, UDP
or 'Raw', the latter being a default for IP socket that is not TCP or UDP.

The classification code is out of date and uses only the socket type
parameter to socket(2) to determine the class of IP socket.  So, any
socket created with SOCK_STREAM will be classified by SELinux as TCP, and
SOCK_DGRAM as UDP.  Also, other socket types such as SOCK_SEQPACKET and
SOCK_DCCP are currently ignored by SELinux, which classifies them as
generic sockets, which means they don't even get basic IP level checking.

This patch changes the SELinux IP socket classification logic, so that
only an IPPROTO_IP protocol value passed to socket(2) classify the socket
as TCP or UDP.  The patch also drops the check for SOCK_RAW and converts
it into a default, so that socket types like SOCK_DCCP and SOCK_SEQPACKET
are classified as SECCLASS_RAWIP_SOCKET (instead of generic sockets).

Note that protocol-specific support for SCTP, DCCP etc. is not addressed
here, we're just getting these protocols checked at the IP layer.

This fixes a reported problem where SCTP sockets were being recognized as
generic SELinux sockets yet still being passed in one case to an IP level
check, which then fails for generic sockets.

It will also fix bugs where any SOCK_STREAM socket is classified as TCP or
any SOCK_DGRAM socket is classified as UDP.

This patch also unifies the way IP sockets classes are determined in
selinux_socket_bind(), so we use the already calculated value instead of
trying to recalculate it.
Signed-off-by: NJames Morris <jmorris@namei.org>
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      13402580
  23. 10 9月, 2005 6 次提交
  25. 30 8月, 2005 1 次提交
  27. 29 7月, 2005 1 次提交
  29. 28 7月, 2005 1 次提交
    • J
      [PATCH] SELinux: default labeling of MLS field · f5c1d5b2
      由 James Morris 提交于 
      Implement kernel labeling of the MLS (multilevel security) field of
security contexts for files which have no existing MLS field.  This is to
enable upgrades of a system from non-MLS to MLS without performing a full
filesystem relabel including all of the mountpoints, which would be quite
painful for users.

With this patch, with MLS enabled, if a file has no MLS field, the kernel
internally adds an MLS field to the in-core inode (but not to the on-disk
file).  This MLS field added is the default for the superblock, allowing
per-mountpoint control over the values via fixed policy or mount options.

This patch has been tested by enabling MLS without relabeling its
filesystem, and seems to be working correctly.
Signed-off-by: NJames Morris <jmorris@redhat.com>
Signed-off-by: NStephen Smalley <sds@epoch.ncsc.mil>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      f5c1d5b2
  31. 30 6月, 2005 1 次提交
    • E
      [PATCH] selinux_sb_copy_data() should not require a whole page · 6931dfc9
      由 Eric Paris 提交于 
      Currently selinux_sb_copy_data requires an entire page be allocated to
*orig when the function is called.  This "requirement" is based on the fact
that we call copy_page(in_save, nosec_save) and in_save = orig when the
data is not FS_BINARY_MOUNTDATA.  This means that if a caller were to call
do_kern_mount with only about 10 bytes of options, they would get passed
here and then we would corrupt PAGE_SIZE - 10 bytes of memory (with all
zeros.)

Currently it appears all in kernel FS's use one page of data so this has
not been a problem.  An out of kernel FS did just what is described above
and it would almost always panic shortly after they tried to mount.  From
looking else where in the kernel it is obvious that this string of data
must always be null terminated.  (See example in do_mount where it always
zeros the last byte.) Thus I suggest we use strcpy in place of copy_page.
In this way we make sure the amount we copy is always less than or equal to
the amount we received and since do_mount is zeroing the last byte this
should be safe for all.
Signed-off-by: NEric Paris <eparis@parisplace.org>
Cc: Stephen Smalley <sds@epoch.ncsc.mil>
Acked-by: NJames Morris <jmorris@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      6931dfc9
  33. 26 6月, 2005 3 次提交
  35. 22 6月, 2005 2 次提交
  37. 14 5月, 2005 1 次提交
  39. 01 5月, 2005 1 次提交
  41. 25 4月, 2005 1 次提交
    • H
      [SELINUX]: Fix ipv6_skip_exthdr() invocation causing OOPS. · 0d3d077c
      由 Herbert Xu 提交于 
      The SELinux hooks invoke ipv6_skip_exthdr() with an incorrect
length final argument.  However, the length argument turns out
to be superfluous.

I was just reading ipv6_skip_exthdr and it occured to me that we can
get rid of len altogether.  The only place where len is used is to
check whether the skb has two bytes for ipv6_opt_hdr.  This check
is done by skb_header_pointer/skb_copy_bits anyway.

Now it might appear that we've made the code slower by deferring
the check to skb_copy_bits.  However, this check should not trigger
in the common case so this is OK.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      0d3d077c
  43. 17 4月, 2005 2 次提交
    • J
      [PATCH] SELinux: add support for NETLINK_KOBJECT_UEVENT · 0c9b7942
      由 James Morris 提交于 
      This patch adds SELinux support for the KOBJECT_UEVENT Netlink family, so
that SELinux can apply finer grained controls to it.  For example, security
policy for hald can be locked down to the KOBJECT_UEVENT Netlink family
only.  Currently, this family simply defaults to the default Netlink socket
class.

Note that some new permission definitions are added to sync with changes in
the core userspace policy package, which auto-generates header files.
Signed-off-by: NJames Morris <jmorris@redhat.com>
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      0c9b7942
    • L
      Linux-2.6.12-rc2 · 1da177e4
      由 Linus Torvalds 提交于 
      Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
      1da177e4