user/sven/linux.git/security, branch v2.6.32.61

keys: fix race with concurrent install_user_keyrings()

2013-06-10T09:42:50Z

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 Signed-off-by: Willy Tarreau

security: fix compile error in commoncap.c

2012-10-07T21:37:27Z

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 [dannf: adjusted to apply to Debian's 2.6.32] Signed-off-by: Willy Tarreau

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

2012-10-07T21:37:26Z

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: Willy Tarreau

ima: free duplicate measurement memory

2012-01-25T21:53:20Z

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

CRED: Fix BUG() upon security_cred_alloc_blank() failure

2011-03-02T14:46:39Z

commit 2edeaa34a6e3f2c43b667f6c4f7b27944b811695 upstream. In cred_alloc_blank() since 2.6.32, abort_creds(new) is called with new->security == NULL and new->magic == 0 when security_cred_alloc_blank() returns an error. As a result, BUG() will be triggered if SELinux is enabled or CONFIG_DEBUG_CREDENTIALS=y. If CONFIG_DEBUG_CREDENTIALS=y, BUG() is called from __invalid_creds() because cred->magic == 0. Failing that, BUG() is called from selinux_cred_free() because selinux_cred_free() is not expecting cred->security == NULL. This does not affect smack_cred_free(), tomoyo_cred_free() or apparmor_cred_free(). Fix these bugs by (1) Set new->magic before calling security_cred_alloc_blank(). (2) Handle null cred->security in creds_are_invalid() and selinux_cred_free(). Signed-off-by: Tetsuo Handa Signed-off-by: David Howells Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

SELinux: do not compute transition labels on mountpoint labeled filesystems

2011-02-17T23:37:12Z

commit 415103f9932d45f7927f4b17e3a9a13834cdb9a1 upstream. selinux_inode_init_security computes transitions sids even for filesystems that use mount point labeling. It shouldn't do that. It should just use the mount point label always and no matter what. This causes 2 problems. 1) it makes file creation slower than it needs to be since we calculate the transition sid and 2) it allows files to be created with a different label than the mount point! # id -Z staff_u:sysadm_r:sysadm_t:s0-s0:c0.c1023 # sesearch --type --class file --source sysadm_t --target tmp_t Found 1 semantic te rules: type_transition sysadm_t tmp_t : file user_tmp_t; # mount -o loop,context="system_u:object_r:tmp_t:s0" /tmp/fs /mnt/tmp # ls -lZ /mnt/tmp drwx------. root root system_u:object_r:tmp_t:s0 lost+found # touch /mnt/tmp/file1 # ls -lZ /mnt/tmp -rw-r--r--. root root staff_u:object_r:user_tmp_t:s0 file1 drwx------. root root system_u:object_r:tmp_t:s0 lost+found Whoops, we have a mount point labeled filesystem tmp_t with a user_tmp_t labeled file! Signed-off-by: Eric Paris Reviewed-by: Reviewed-by: James Morris Signed-off-by: Greg Kroah-Hartman

SELinux: define permissions for DCB netlink messages

2011-02-17T23:37:11Z

commit 350e4f31e0eaf56dfc3b328d24a11bdf42a41fb8 upstream. Commit 2f90b865 added two new netlink message types to the netlink route socket. SELinux has hooks to define if netlink messages are allowed to be sent or received, but it did not know about these two new message types. By default we allow such actions so noone likely noticed. This patch adds the proper definitions and thus proper permissions enforcement. Signed-off-by: Eric Paris Cc: James Morris Signed-off-by: Greg Kroah-Hartman

ima: fix add LSM rule bug

2011-01-07T22:43:17Z

commit 867c20265459d30a01b021a9c1e81fb4c5832aa9 upstream. If security_filter_rule_init() doesn't return a rule, then not everything is as fine as the return code implies. This bug only occurs when the LSM (eg. SELinux) is disabled at runtime. Adding an empty LSM rule causes ima_match_rules() to always succeed, ignoring any remaining rules. default IMA TCB policy: # PROC_SUPER_MAGIC dont_measure fsmagic=0x9fa0 # SYSFS_MAGIC dont_measure fsmagic=0x62656572 # DEBUGFS_MAGIC dont_measure fsmagic=0x64626720 # TMPFS_MAGIC dont_measure fsmagic=0x01021994 # SECURITYFS_MAGIC dont_measure fsmagic=0x73636673 < LSM specific rule > dont_measure obj_type=var_log_t measure func=BPRM_CHECK measure func=FILE_MMAP mask=MAY_EXEC measure func=FILE_CHECK mask=MAY_READ uid=0 Thus without the patch, with the boot parameters 'tcb selinux=0', adding the above 'dont_measure obj_type=var_log_t' rule to the default IMA TCB measurement policy, would result in nothing being measured. The patch prevents the default TCB policy from being replaced. Signed-off-by: Mimi Zohar Cc: James Morris Acked-by: Serge Hallyn Cc: David Safford Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

KEYS: Fix bug in keyctl_session_to_parent() if parent has no session keyring

2010-09-27T00:21:30Z

commit 3d96406c7da1ed5811ea52a3b0905f4f0e295376 upstream. Fix a bug in keyctl_session_to_parent() whereby it tries to check the ownership of the parent process's session keyring whether or not the parent has a session keyring [CVE-2010-2960]. This results in the following oops: BUG: unable to handle kernel NULL pointer dereference at 00000000000000a0 IP: [] keyctl_session_to_parent+0x251/0x443 ... Call Trace: [] ? keyctl_session_to_parent+0x67/0x443 [] ? __do_fault+0x24b/0x3d0 [] sys_keyctl+0xb4/0xb8 [] system_call_fastpath+0x16/0x1b if the parent process has no session keyring. If the system is using pam_keyinit then it mostly protected against this as all processes derived from a login will have inherited the session keyring created by pam_keyinit during the log in procedure. To test this, pam_keyinit calls need to be commented out in /etc/pam.d/. Reported-by: Tavis Ormandy Signed-off-by: David Howells Acked-by: Tavis Ormandy Cc: dann frazier Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

KEYS: Fix RCU no-lock warning in keyctl_session_to_parent()

2010-09-27T00:21:30Z

commit 9d1ac65a9698513d00e5608d93fca0c53f536c14 upstream. There's an protected access to the parent process's credentials in the middle of keyctl_session_to_parent(). This results in the following RCU warning: =================================================== [ INFO: suspicious rcu_dereference_check() usage. ] --------------------------------------------------- security/keys/keyctl.c:1291 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 keyctl-session-/2137: #0: (tasklist_lock){.+.+..}, at: [] keyctl_session_to_parent+0x60/0x236 stack backtrace: Pid: 2137, comm: keyctl-session- Not tainted 2.6.36-rc2-cachefs+ #1 Call Trace: [] lockdep_rcu_dereference+0xaa/0xb3 [] keyctl_session_to_parent+0xed/0x236 [] sys_keyctl+0xb4/0xb6 [] system_call_fastpath+0x16/0x1b The code should take the RCU read lock to make sure the parents credentials don't go away, even though it's holding a spinlock and has IRQ disabled. Signed-off-by: David Howells Signed-off-by: Linus Torvalds Cc: dann frazier Signed-off-by: Greg Kroah-Hartman