kernel/linux.git/security, branch v3.0.69

keys: fix race with concurrent install_user_keyrings()

2013-03-14T18:32:06+00:00

commit 0da9dfdd2cd9889201bc6f6f43580c99165cd087 upstream. This fixes CVE-2013-1792. There is a race in install_user_keyrings() that can cause a NULL pointer dereference when called concurrently for the same user if the uid and uid-session keyrings are not yet created. It might be possible for an unprivileged user to trigger this by calling keyctl() from userspace in parallel immediately after logging in. Assume that we have two threads both executing lookup_user_key(), both looking for KEY_SPEC_USER_SESSION_KEYRING. THREAD A THREAD B =============================== =============================== ==>call install_user_keyrings(); if (!cred->user->session_keyring) ==>call install_user_keyrings() ... user->uid_keyring = uid_keyring; if (user->uid_keyring) return 0; <== key = cred->user->session_keyring [== NULL] user->session_keyring = session_keyring; atomic_inc(&key->usage); [oops] At the point thread A dereferences cred->user->session_keyring, thread B hasn't updated user->session_keyring yet, but thread A assumes it is populated because install_user_keyrings() returned ok. The race window is really small but can be exploited if, for example, thread B is interrupted or preempted after initializing uid_keyring, but before doing setting session_keyring. This couldn't be reproduced on a stock kernel. However, after placing systemtap probe on 'user->session_keyring = session_keyring;' that introduced some delay, the kernel could be crashed reliably. Fix this by checking both pointers before deciding whether to return. Alternatively, the test could be done away with entirely as it is checked inside the mutex - but since the mutex is global, that may not be the best way. Signed-off-by: David Howells Reported-by: Mateusz Guzik Signed-off-by: Andrew Morton Signed-off-by: James Morris Signed-off-by: Greg Kroah-Hartman

selinux: fix sel_netnode_insert() suspicious rcu dereference

2012-11-26T19:34:56+00:00

commit 88a693b5c1287be4da937699cb82068ce9db0135 upstream. =============================== [ INFO: suspicious RCU usage. ] 3.5.0-rc1+ #63 Not tainted ------------------------------- security/selinux/netnode.c:178 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 0 1 lock held by trinity-child1/8750: #0: (sel_netnode_lock){+.....}, at: [] sel_netnode_sid+0x16a/0x3e0 stack backtrace: Pid: 8750, comm: trinity-child1 Not tainted 3.5.0-rc1+ #63 Call Trace: [] lockdep_rcu_suspicious+0xfd/0x130 [] sel_netnode_sid+0x3b1/0x3e0 [] ? sel_netnode_find+0x1a0/0x1a0 [] selinux_socket_bind+0xf6/0x2c0 [] ? trace_hardirqs_off+0xd/0x10 [] ? lock_release_holdtime.part.9+0x15/0x1a0 [] ? lock_hrtimer_base+0x31/0x60 [] security_socket_bind+0x16/0x20 [] sys_bind+0x7a/0x100 [] ? sysret_check+0x22/0x5d [] ? trace_hardirqs_on_caller+0x10d/0x1a0 [] ? trace_hardirqs_on_thunk+0x3a/0x3f [] system_call_fastpath+0x16/0x1b This patch below does what Paul McKenney suggested in the previous thread. Signed-off-by: Dave Jones Reviewed-by: Paul E. McKenney Acked-by: Paul Moore Cc: Eric Paris Signed-off-by: Andrew Morton Signed-off-by: James Morris Signed-off-by: Greg Kroah-Hartman

SELinux: if sel_make_bools errors don't leave inconsistent state

2012-06-01T07:12:54+00:00

commit 154c50ca4eb9ae472f50b6a481213e21ead4457d upstream. We reset the bool names and values array to NULL, but do not reset the number of entries in these arrays to 0. If we error out and then get back into this function we will walk these NULL pointers based on the belief that they are non-zero length. Signed-off-by: Eric Paris Signed-off-by: Greg Kroah-Hartman

security: fix compile error in commoncap.c

2012-04-22T23:21:43+00:00

commit 51b79bee627d526199b2f6a6bef8ee0c0739b6d1 upstream. Add missing "personality.h" security/commoncap.c: In function 'cap_bprm_set_creds': security/commoncap.c:510: error: 'PER_CLEAR_ON_SETID' undeclared (first use in this function) security/commoncap.c:510: error: (Each undeclared identifier is reported only once security/commoncap.c:510: error: for each function it appears in.) Signed-off-by: Jonghwan Choi Acked-by: Serge Hallyn Signed-off-by: James Morris Cc: Eric Paris Signed-off-by: Greg Kroah-Hartman

fcaps: clear the same personality flags as suid when fcaps are used

2012-04-22T23:21:41+00:00

commit d52fc5dde171f030170a6cb78034d166b13c9445 upstream. If a process increases permissions using fcaps all of the dangerous personality flags which are cleared for suid apps should also be cleared. Thus programs given priviledge with fcaps will continue to have address space randomization enabled even if the parent tried to disable it to make it easier to attack. Signed-off-by: Eric Paris Reviewed-by: Serge Hallyn Signed-off-by: James Morris Signed-off-by: Greg Kroah-Hartman

TOMOYO: Fix mount flags checking order.

2012-04-13T15:14:08+00:00

commit df91e49477a9be15921cb2854e1d12a3bdb5e425 upstream. Userspace can pass in arbitrary combinations of MS_* flags to mount(). If both MS_BIND and one of MS_SHARED/MS_PRIVATE/MS_SLAVE/MS_UNBINDABLE are passed, device name which should be checked for MS_BIND was not checked because MS_SHARED/MS_PRIVATE/MS_SLAVE/MS_UNBINDABLE had higher priority than MS_BIND. If both one of MS_BIND/MS_MOVE and MS_REMOUNT are passed, device name which should not be checked for MS_REMOUNT was checked because MS_BIND/MS_MOVE had higher priority than MS_REMOUNT. Fix these bugs by changing priority to MS_REMOUNT -> MS_BIND -> MS_SHARED/MS_PRIVATE/MS_SLAVE/MS_UNBINDABLE -> MS_MOVE as with do_mount() does. Also, unconditionally return -EINVAL if more than one of MS_SHARED/MS_PRIVATE/MS_SLAVE/MS_UNBINDABLE is passed so that TOMOYO will not generate inaccurate audit logs, for commit 7a2e8a8f "VFS: Sanity check mount flags passed to change_mnt_propagation()" clarified that these flags must be exclusively passed. Signed-off-by: Tetsuo Handa Signed-off-by: James Morris Signed-off-by: Jonathan Nieder Signed-off-by: Greg Kroah-Hartman

ima: fix invalid memory reference

2012-01-26T01:24:41+00:00

commit 7b7e5916aa2f46e57f8bd8cb89c34620ebfda5da upstream. Don't free a valid measurement entry on TPM PCR extend failure. Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar Signed-off-by: Greg Kroah-Hartman

ima: free duplicate measurement memory

2012-01-26T01:24:41+00:00

commit 45fae7493970d7c45626ccd96d4a74f5f1eea5a9 upstream. Info about new measurements are cached in the iint for performance. When the inode is flushed from cache, the associated iint is flushed as well. Subsequent access to the inode will cause the inode to be re-measured and will attempt to add a duplicate entry to the measurement list. This patch frees the duplicate measurement memory, fixing a memory leak. Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar Signed-off-by: Greg Kroah-Hartman

SELinux: Fix RCU deref check warning in sel_netport_insert()

2012-01-06T22:13:52+00:00

commit 50345f1ea9cda4618d9c26e590a97ecd4bc7ac75 upstream. Fix the following bug in sel_netport_insert() where rcu_dereference() should be rcu_dereference_protected() as sel_netport_lock is held. =================================================== [ INFO: suspicious rcu_dereference_check() usage. ] --------------------------------------------------- security/selinux/netport.c:127 invoked rcu_dereference_check() without protection! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 0 1 lock held by ossec-rootcheck/3323: #0: (sel_netport_lock){+.....}, at: [] sel_netport_sid+0xbb/0x226 stack backtrace: Pid: 3323, comm: ossec-rootcheck Not tainted 3.1.0-rc8-fsdevel+ #1095 Call Trace: [] lockdep_rcu_dereference+0xa7/0xb0 [] sel_netport_sid+0x1b7/0x226 [] ? sel_netport_avc_callback+0xbc/0xbc [] selinux_socket_bind+0x115/0x230 [] ? might_fault+0x4e/0x9e [] ? might_fault+0x97/0x9e [] security_socket_bind+0x11/0x13 [] sys_bind+0x56/0x95 [] ? sysret_check+0x27/0x62 [] ? trace_hardirqs_on_caller+0x11e/0x155 [] ? audit_syscall_entry+0x17b/0x1ae [] ? trace_hardirqs_on_thunk+0x3a/0x3f [] system_call_fastpath+0x16/0x1b Signed-off-by: David Howells Acked-by: Paul Moore Acked-by: Eric Dumazet Signed-off-by: James Morris Signed-off-by: Greg Kroah-Hartman

fix apparmor dereferencing potentially freed dentry, sanitize __d_path() API

2011-12-21T20:57:36+00:00

commit 02125a826459a6ad142f8d91c5b6357562f96615 upstream. __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 ACKed-by: John Johansen Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman