replace_fd() began with "eats a reference, tries to insert into
descriptor table" semantics; at some point I'd switched it to
much saner current behaviour ("try to insert into descriptor
table, grabbing a new reference if inserted; caller should do
fput() in any case"), but forgot to update the callers.
Mea culpa...

[Spotted by Pavel Roskin, who has really weird system with pipe-fed
coredumps as part of what he considers a normal boot ;-)]
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

simplifies a bunch of callers...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

iterates through the opened files in given descriptor table,
calling a supplied function; we stop once non-zero is returned.
Callback gets struct file *, descriptor number and const void *
argument passed to iterator.  It is called with files->file_lock
held, so it is not allowed to block.

tty_io, netprio_cgroup and selinux flush_unauthorized_files()
converted to its use.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

When we restore file descriptors we would like them to look exactly as
they were at dumping time.

With help of fcntl it's almost possible, the missing snippet is file
owners UIDs.

To be able to read their values the F_GETOWNER_UIDS is introduced.

This option is valid iif CONFIG_CHECKPOINT_RESTORE is turned on, otherwise
returning -EINVAL.
Signed-off-by: NCyrill Gorcunov <gorcunov@openvz.org>
Acked-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

OK, what we have so far is e.g.
	setxattr(path, name, whatever, 0, XATTR_REPLACE)
with name being good enough to get through xattr_permission().
Then we reach security_inode_setxattr() with the desired value and size.
Aha.  name should begin with "security.selinux", or we won't get that
far in selinux_inode_setxattr().  Suppose we got there and have enough
permissions to relabel that sucker.  We call security_context_to_sid()
with value == NULL, size == 0.  OK, we want ss_initialized to be non-zero.
I.e. after everything had been set up and running.  No problem...

We do 1-byte kmalloc(), zero-length memcpy() (which doesn't oops, even
thought the source is NULL) and put a NUL there.  I.e. form an empty
string.  string_to_context_struct() is called and looks for the first
':' in there.  Not found, -EINVAL we get.  OK, security_context_to_sid_core()
has rc == -EINVAL, force == 0, so it silently returns -EINVAL.
All it takes now is not having CAP_MAC_ADMIN and we are fucked.

All right, it might be a different bug (modulo strange code quoted in the
report), but it's real.  Easily fixed, AFAICS:

Deal with size == 0, value == NULL case in selinux_inode_setxattr()

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Tested-by: NDave Jones <davej@redhat.com>
Reported-by: NDave Jones <davej@redhat.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

Recently, glibc made a change to suppress sign-conversion warnings in
FD_SET (glibc commit ceb9e56b3d1).  This uncovered an issue with the
kernel's definition of __NFDBITS if applications #include
<linux/types.h> after including <sys/select.h>.  A build failure would
be seen when passing the -Werror=sign-compare and -D_FORTIFY_SOURCE=2
flags to gcc.

It was suggested that the kernel should either match the glibc
definition of __NFDBITS or remove that entirely.  The current in-kernel
uses of __NFDBITS can be replaced with BITS_PER_LONG, and there are no
uses of the related __FDELT and __FDMASK defines.  Given that, we'll
continue the cleanup that was started with commit 8b3d1cda
("posix_types: Remove fd_set macros") and drop the remaining unused
macros.

Additionally, linux/time.h has similar macros defined that expand to
nothing so we'll remove those at the same time.
Reported-by: NJeff Law <law@redhat.com>
Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org>
CC: <stable@vger.kernel.org>
Signed-off-by: NJosh Boyer <jwboyer@redhat.com>
[ .. and fix up whitespace as per akpm ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

When I introduced open perms policy didn't understand them and I
implemented them as a policycap.  When I added the checking of open perm
to truncate I forgot to conditionalize it on the userspace defined
policy capability.  Running an old policy with a new kernel will not
check open on open(2) but will check it on truncate.  Conditionalize the
truncate check the same as the open check.
Signed-off-by: NEric Paris <eparis@redhat.com>
Cc: stable@vger.kernel.org # 3.4.x
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

This patch is a cleanup. Use NFPROTO_* for consistency with other
netfilter code.
Signed-off-by: NAlban Crequy <alban.crequy@collabora.co.uk>
Reviewed-by: NJavier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: NVincent Sanders <vincent.sanders@collabora.co.uk>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

... i.e. file-dependent and address-dependent checks.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... switch callers.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

With this change, calling
  prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)
disables privilege granting operations at execve-time.  For example, a
process will not be able to execute a setuid binary to change their uid
or gid if this bit is set.  The same is true for file capabilities.

Additionally, LSM_UNSAFE_NO_NEW_PRIVS is defined to ensure that
LSMs respect the requested behavior.

To determine if the NO_NEW_PRIVS bit is set, a task may call
  prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0);
It returns 1 if set and 0 if it is not set. If any of the arguments are
non-zero, it will return -1 and set errno to -EINVAL.
(PR_SET_NO_NEW_PRIVS behaves similarly.)

This functionality is desired for the proposed seccomp filter patch
series.  By using PR_SET_NO_NEW_PRIVS, it allows a task to modify the
system call behavior for itself and its child tasks without being
able to impact the behavior of a more privileged task.

Another potential use is making certain privileged operations
unprivileged.  For example, chroot may be considered "safe" if it cannot
affect privileged tasks.

Note, this patch causes execve to fail when PR_SET_NO_NEW_PRIVS is
set and AppArmor is in use.  It is fixed in a subsequent patch.
Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
Signed-off-by: NWill Drewry <wad@chromium.org>
Acked-by: NEric Paris <eparis@redhat.com>
Acked-by: NKees Cook <keescook@chromium.org>

v18: updated change desc
v17: using new define values as per 3.4
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

We don't need this variable and it just eats stack space.  Remove it.
Signed-off-by: NEric Paris <eparis@redhat.com>

We no longer need the distinction.  We only need data after we decide to do an
audit.  So turn the "late" audit data into just "data" and remove what we
currently have as "data".
Signed-off-by: NEric Paris <eparis@redhat.com>

It isn't needed.  If you don't set the type of the data associated with
that type it is a pretty obvious programming bug.  So why waste the cycles?
Signed-off-by: NEric Paris <eparis@redhat.com>

There are no legitimate users.  Always use current and get back some stack
space for the common_audit_data.
Signed-off-by: NEric Paris <eparis@redhat.com>

Just open code it so grep on the source code works better.
Signed-off-by: NEric Paris <eparis@redhat.com>

selinux_inode_has_perm is a hot path.  Instead of declaring the
common_audit_data on the stack move it to a noinline function only used in
the rare case we need to send an audit message.
Signed-off-by: NEric Paris <eparis@redhat.com>

Both callers could better be using file_has_perm() to get better audit
results.
Signed-off-by: NEric Paris <eparis@redhat.com>

We pay a rather large overhead initializing the common_audit_data.
Since we only need this information if we actually emit an audit
message there is little need to set it up in the hot path.  This patch
splits the functionality of avc_has_perm() into avc_has_perm_noaudit(),
avc_audit_required() and slow_avc_audit().  But we take care of setting
up to audit between required() and the actual audit call.  Thus saving
measurable time in a hot path.
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NEric Paris <eparis@redhat.com>

We know that some yum operation is causing CAP_MAC_ADMIN failures.  This
implies that an RPM is laying down (or attempting to lay down) a file with
an invalid label.  The problem is that we don't have any information to
track down the cause.  This patch will cause such a failure to report the
failed label in an SELINUX_ERR audit message.  This is similar to the
SELINUX_ERR reports on invalid transitions and things like that.  It should
help run down problems on what is trying to set invalid labels in the
future.

Resulting records look something like:
type=AVC msg=audit(1319659241.138:71): avc:  denied  { mac_admin } for pid=2594 comm="chcon" capability=33 scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=capability2
type=SELINUX_ERR msg=audit(1319659241.138:71): op=setxattr invalid_context=unconfined_u:object_r:hello:s0
type=SYSCALL msg=audit(1319659241.138:71): arch=c000003e syscall=188 success=no exit=-22 a0=a2c0e0 a1=390341b79b a2=a2d620 a3=1f items=1 ppid=2519 pid=2594 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=1 comm="chcon" exe="/usr/bin/chcon" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)
type=CWD msg=audit(1319659241.138:71):  cwd="/root" type=PATH msg=audit(1319659241.138:71): item=0 name="test" inode=785879 dev=fc:03 mode=0100644 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:admin_home_t:s0
Signed-off-by: NEric Paris <eparis@redhat.com>

dentry_open takes a file, rename it to file_open
Signed-off-by: NEric Paris <eparis@redhat.com>

In RH BZ 578841 we realized that the SELinux sandbox program was allowed to
truncate files outside of the sandbox.  The reason is because sandbox
confinement is determined almost entirely by the 'open' permission.  The idea
was that if the sandbox was unable to open() files it would be unable to do
harm to those files.  This turns out to be false in light of syscalls like
truncate() and chmod() which don't require a previous open() call.  I looked
at the syscalls that did not have an associated 'open' check and found that
truncate(), did not have a seperate permission and even if it did have a
separate permission such a permission owuld be inadequate for use by
sandbox (since it owuld have to be granted so liberally as to be useless).
This patch checks the OPEN permission on truncate.  I think a better solution
for sandbox is a whole new permission, but at least this fixes what we have
today.
Signed-off-by: NEric Paris <eparis@redhat.com>

After shrinking the common_audit_data stack usage for private LSM data I'm
not going to shrink the data union.  To do this I'm going to move anything
larger than 2 void * ptrs to it's own structure and require it to be declared
separately on the calling stack.  Thus hot paths which don't need more than
a couple pointer don't have to declare space to hold large unneeded
structures.  I could get this down to one void * by dealing with the key
struct and the struct path.  We'll see if that is helpful after taking care of
networking.
Signed-off-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Linus found that the gigantic size of the common audit data caused a big
perf hit on something as simple as running stat() in a loop.  This patch
requires LSMs to declare the LSM specific portion separately rather than
doing it in a union.  Thus each LSM can be responsible for shrinking their
portion and don't have to pay a penalty just because other LSMs have a
bigger space requirement.
Signed-off-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Replace the fd_sets in struct fdtable with an array of unsigned longs and then
use the standard non-atomic bit operations rather than the FD_* macros.

This:

 (1) Removes the abuses of struct fd_set:

     (a) Since we don't want to allocate a full fd_set the vast majority of the
     	 time, we actually, in effect, just allocate a just-big-enough array of
     	 unsigned longs and cast it to an fd_set type - so why bother with the
     	 fd_set at all?

     (b) Some places outside of the core fdtable handling code (such as
     	 SELinux) want to look inside the array of unsigned longs hidden inside
     	 the fd_set struct for more efficient iteration over the entire set.

 (2) Eliminates the use of FD_*() macros in the kernel completely.

 (3) Permits the __FD_*() macros to be deleted entirely where not exposed to
     userspace.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/20120216174954.23314.48147.stgit@warthog.procyon.org.ukSigned-off-by: NH. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>

Trim security.h
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJames Morris <jmorris@namei.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Once upon a time netlink was not sync and we had to get the effective
capabilities from the skb that was being received.  Today we instead get
the capabilities from the current task.  This has rendered the entire
purpose of the hook moot as it is now functionally equivalent to the
capable() call.
Signed-off-by: NEric Paris <eparis@redhat.com>

Reading /proc/pid/stat of another process checks if one has ptrace permissions
on that process.  If one does have permissions it outputs some data about the
process which might have security and attack implications.  If the current
task does not have ptrace permissions the read still works, but those fields
are filled with inocuous (0) values.  Since this check and a subsequent denial
is not a violation of the security policy we should not audit such denials.

This can be quite useful to removing ptrace broadly across a system without
flooding the logs when ps is run or something which harmlessly walks proc.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NSerge E. Hallyn <serge.hallyn@canonical.com>

The capabilities framework is based around credentials, not necessarily the
current task.  Yet we still passed the current task down into LSMs from the
security_capable() LSM hook as if it was a meaningful portion of the security
decision.  This patch removes the 'generic' passing of current and instead
forces individual LSMs to use current explicitly if they think it is
appropriate.  In our case those LSMs are SELinux and AppArmor.

I believe the AppArmor use of current is incorrect, but that is wholely
unrelated to this patch.  This patch does not change what AppArmor does, it
just makes it clear in the AppArmor code that it is doing it.

The SELinux code still uses current in it's audit message, which may also be
wrong and needs further investigation.  Again this is NOT a change, it may
have always been wrong, this patch just makes it clear what is happening.
Signed-off-by: NEric Paris <eparis@redhat.com>

Fix several sparse warnings in the SELinux security server code.
Signed-off-by: NJames Morris <jmorris@namei.org>
Signed-off-by: NEric Paris <eparis@redhat.com>

Fix sparse warnings in SELinux Netlink code.
Signed-off-by: NJames Morris <jmorris@namei.org>
Signed-off-by: NEric Paris <eparis@redhat.com>

Fixes several sparse warnings for selinuxfs.c
Signed-off-by: NJames Morris <jmorris@namei.org>
Signed-off-by: NEric Paris <eparis@redhat.com>

Sparse fix: make selinux_secmark_refcount  static.
Signed-off-by: NJames Morris <jmorris@namei.org>
Signed-off-by: NEric Paris <eparis@redhat.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>