BugLink: http://bugs.launchpad.net/bugs/955892
All failures from __d_path where being treated as disconnected paths,
however __d_path can also fail when the generated pathname is too long.
The initial ENAMETOOLONG error was being lost, and ENAMETOOLONG was only
returned if the subsequent dentry_path call resulted in that error. Other
wise if the path was split across a mount point such that the dentry_path
fit within the buffer when the __d_path did not the failure was treated
as a disconnected path.
Signed-off-by: John Johansen <john.johansen@canonical.com>
BugLink: http://bugs.launchpad.net/bugs/978038
also affects apparmor portion of
BugLink: http://bugs.launchpad.net/bugs/987371
The unconfined profile is not stored in the regular profile list, but
change_profile and exec transitions may want access to it when setting
up specialized transitions like switch to the unconfined profile of a
new policy namespace.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Add support for AppArmor to explicitly fail requested domain transitions
if NO_NEW_PRIVS is set and the task is not unconfined.
Transitions from unconfined are still allowed because this always results
in a reduction of privileges.
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Will Drewry <wad@chromium.org>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
v18: new acked-by, new description
Signed-off-by: James Morris <james.l.morris@oracle.com>
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: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Will Drewry <wad@chromium.org>
Acked-by: Eric Paris <eparis@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
v18: updated change desc
v17: using new define values as per 3.4
Signed-off-by: James Morris <james.l.morris@oracle.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: Eric Paris <eparis@redhat.com>
apparmor is the only LSM that uses the common_audit_data tsk field.
Instead of making all LSMs pay for the stack space move the aa usage into
the apparmor_audit_data.
Signed-off-by: Eric Paris <eparis@redhat.com>
It just bloats the audit data structure for no good reason, since the
only time those fields are filled are just before calling the
common_lsm_audit() function, which is also the only user of those
fields.
So just make them be the arguments to common_lsm_audit(), rather than
bloating that structure that is passed around everywhere, and is
initialized in hot paths.
Signed-off-by: Linus 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: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix failure in aa_change_onexec api when the request is made from a confined
task. This failure was caused by two problems
The AA_MAY_ONEXEC perm was not being mapped correctly for this case.
The executable name was being checked as second time instead of using the
requested onexec profile name, which may not be the same as the exec
profile name. This mistake can not be exploited to grant extra permission
because of the above flaw where the ONEXEC permission was not being mapped
so it will not be granted.
BugLink: http://bugs.launchpad.net/bugs/963756
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Add the base support for the new policy extensions. This does not bring
any additional functionality, or change current semantics.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
Move the path name lookup failure messages into the main path name lookup
routine, as the information is useful in more than just aa_path_perm.
Also rename aa_get_name to aa_path_name as it is not getting a reference
counted object with a corresponding put fn.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
Update aa_dfa_match so that it doesn't result in an input string being
walked twice (once to get its length and another time to match)
Add a single step functions
aa_dfa_next
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
When __d_path and d_absolute_path fail due to the name being outside of
the current namespace no name is reported. Use dentry_path to provide
some hint as to which file was being accessed.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
Post unpacking of policy a verification pass is made on x transition
indexes. When this fails a call to audit_iface is made resulting in an
oops, because audit_iface is expecting a valid buffer position but
since the failure comes from post unpack verification there is none.
Make the position argument optional so that audit_iface can be called
from post unpack verification.
Signed-off-by: John Johansen <john.johansen@canonical.com>
The returning of -ESATLE when a path lookup fails as disconnected is wrong.
Since AppArmor is rejecting the access return -EACCES instead.
This also fixes a bug in complain (learning) mode where disconnected paths
are denied because -ESTALE errors are not ignored causing failures that
can change application behavior.
Signed-off-by: John Johansen <john.johansen@canonical.com>
When a chroot relative pathname lookup fails it is falling through to
do a d_absolute_path lookup. This is incorrect as d_absolute_path should
only be used to lookup names for namespace absolute paths.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
The mapping of AA_MAY_META_READ for the allow mask was also being mapped
to the audit and quiet masks. This would result in some operations being
audited when the should not.
This flaw was hidden by the previous audit bug which would drop some
messages that where supposed to be audited.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
If the xindex value stored in the accept tables is 0, the extraction of
that value will result in an underflow (0 - 4).
In properly compiled policy this should not happen for file rules but
it may be possible for other rule types in the future.
To exploit this underflow a user would have to be able to load a corrupt
policy, which requires CAP_MAC_ADMIN, overwrite system policy in kernel
memory or know of a compiler error resulting in the flaw being present
for loaded policy (no such flaw is known at this time).
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
The audit permission flag, that specifies an audit message should be
provided when an operation is allowed, was being ignored in some cases.
This is because the auto audit mode (which determines the audit mode from
system flags) was incorrectly assigned the same value as audit mode. The
shared value would result in messages that should be audited going through
a second evaluation as to whether they should be audited based on the
auto audit, resulting in some messages being dropped.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
The unpacking of struct capsx is missing a check for the end of the
caps structure. This can lead to unpack failures depending on what else
is packed into the policy file being unpacked.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
Since the parser needs to know which rlimits are known to the kernel,
export the list via a mask file in the "rlimit" subdirectory in the
securityfs "features" directory.
Signed-off-by: Kees Cook <kees@ubuntu.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Create the "file" directory in the securityfs for tracking features
related to files.
Signed-off-by: Kees Cook <kees@ubuntu.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
This adds the "features" subdirectory to the AppArmor securityfs
to display boolean features flags and the known capability mask.
Signed-off-by: Kees Cook <kees@ubuntu.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Use a file tree structure to represent the AppArmor securityfs.
Signed-off-by: Kees Cook <kees@ubuntu.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
module_param(bool) used to counter-intuitively take an int. In
fddd5201 (mid-2009) we allowed bool or int/unsigned int using a messy
trick.
It's time to remove the int/unsigned int option. For this version
it'll simply give a warning, but it'll break next kernel version.
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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: Eric Paris <eparis@redhat.com>
it's not needed anymore; we used to, back when we had to do
mount_subtree() by hand, complete with put_mnt_ns() in it.
No more... Apparmor didn't need it since the __d_path() fix.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The 'aabool' wrappers actually pass off to the 'bool' parse functions,
so you should use the same check function. Similarly for aauint and
uint.
(Note that 'bool' module parameters also allow 'int', which is why you
got away with this, but that's changing very soon.)
Cc: linux-security-module@vger.kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
Adds a missed rcu_dereference() around real_parent.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
__d_path() API is asking for trouble and in case of apparmor d_namespace_path()
getting just that. The root cause is that when __d_path() misses the root
it had been told to look for, it stores the location of the most remote ancestor
in *root. Without grabbing references. Sure, at the moment of call it had
been pinned down by what we have in *path. And if we raced with umount -l, we
could have very well stopped at vfsmount/dentry that got freed as soon as
prepend_path() dropped vfsmount_lock.
It is safe to compare these pointers with pre-existing (and known to be still
alive) vfsmount and dentry, as long as all we are asking is "is it the same
address?". Dereferencing is not safe and apparmor ended up stepping into
that. d_namespace_path() really wants to examine the place where we stopped,
even if it's not connected to our namespace. As the result, it looked
at ->d_sb->s_magic of a dentry that might've been already freed by that point.
All other callers had been careful enough to avoid that, but it's really
a bad interface - it invites that kind of trouble.
The fix is fairly straightforward, even though it's bigger than I'd like:
* prepend_path() root argument becomes const.
* __d_path() is never called with NULL/NULL root. It was a kludge
to start with. Instead, we have an explicit function - d_absolute_root().
Same as __d_path(), except that it doesn't get root passed and stops where
it stops. apparmor and tomoyo are using it.
* __d_path() returns NULL on path outside of root. The main
caller is show_mountinfo() and that's precisely what we pass root for - to
skip those outside chroot jail. Those who don't want that can (and do)
use d_path().
* __d_path() root argument becomes const. Everyone agrees, I hope.
* apparmor does *NOT* try to use __d_path() or any of its variants
when it sees that path->mnt is an internal vfsmount. In that case it's
definitely not mounted anywhere and dentry_path() is exactly what we want
there. Handling of sysctl()-triggered weirdness is moved to that place.
* if apparmor is asked to do pathname relative to chroot jail
and __d_path() tells it we it's not in that jail, the sucker just calls
d_absolute_path() instead. That's the other remaining caller of __d_path(),
BTW.
* seq_path_root() does _NOT_ return -ENAMETOOLONG (it's stupid anyway -
the normal seq_file logics will take care of growing the buffer and redoing
the call of ->show() just fine). However, if it gets path not reachable
from root, it returns SEQ_SKIP. The only caller adjusted (i.e. stopped
ignoring the return value as it used to do).
Reviewed-by: John Johansen <john.johansen@canonical.com>
ACKed-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
Fix sparse warnings:
security/apparmor/procattr.c:35:5: warning: symbol 'aa_getprocattr' was not declared. Should it be static?
security/apparmor/procattr.c:113:5: warning: symbol 'aa_setprocattr_changehat' was not declared. Should it be static?
security/apparmor/procattr.c:158:5: warning: symbol 'aa_setprocattr_changeprofile' was not declared. Should it be static?
security/apparmor/procattr.c:166:5: warning: symbol 'aa_setprocattr_permipc' was not declared. Should it be static?
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: John Johansen <john.johansen@canonical.com>
Fix the following warnings:
security/apparmor/policy_unpack.c:384:35: warning: symbol 'size' shadows an earlier one
security/apparmor/policy_unpack.c:370:24: originally declared here
security/apparmor/policy_unpack.c:443:29: warning: symbol 'tmp' shadows an earlier one
security/apparmor/policy_unpack.c:434:21: originally declared here
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: John Johansen <john.johansen@canonical.com>
Fix the following sparse warnings:
security/apparmor/lib.c:37:6: warning: symbol 'aa_split_fqname' was not declared. Should it be static?
security/apparmor/lib.c:63:6: warning: symbol 'aa_info_message' was not declared. Should it be static?
security/apparmor/lib.c:83:6: warning: symbol 'kvmalloc' was not declared. Should it be static?
security/apparmor/lib.c:123:6: warning: symbol 'kvfree' was not declared. Should it be static?
Signed-off-by: James Morris <jmorris@namei.org>
Include ipc.h to eliminate sparse warnings.
security/apparmor/ipc.c:61:5: warning: symbol 'aa_may_ptrace' was not declared. Should it be static?
security/apparmor/ipc.c:83:5: warning: symbol 'aa_ptrace' was not declared. Should it be static
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: John Johansen <john.johansen@canonical.com>
AppArmor is masking the capabilities returned by capget against the
capabilities mask in the profile. This is wrong, in complain mode the
profile has effectively all capabilities, as the profile restrictions are
not being enforced, merely tested against to determine if an access is
known by the profile.
This can result in the wrong behavior of security conscience applications
like sshd which examine their capability set, and change their behavior
accordingly. In this case because of the masked capability set being
returned sshd fails due to DAC checks, even when the profile is in complain
mode.
Kernels affected: 2.6.36 - 3.0.
Signed-off-by: John Johansen <john.johansen@canonical.com>
The pointer returned from tracehook_tracer_task() is only valid inside
the rcu_read_lock. However the tracer pointer obtained is being passed
to aa_may_ptrace outside of the rcu_read_lock critical section.
Mover the aa_may_ptrace test into the rcu_read_lock critical section, to
fix this.
Kernels affected: 2.6.36 - 3.0
Reported-by: Oleg Nesterov <oleg@redhat.com>
Cc: stable@kernel.org
Signed-off-by: John Johansen <john.johansen@canonical.com>
Al Viro