user/sven/linux.git/security, branch v3.14.16

evm: prohibit userspace writing 'security.evm' HMAC value

2014-06-26T19:15:38Z

commit 2fb1c9a4f2dbc2f0bd2431c7fa64d0b5483864e4 upstream. Calculating the 'security.evm' HMAC value requires access to the EVM encrypted key. Only the kernel should have access to it. This patch prevents userspace tools(eg. setfattr, cp --preserve=xattr) from setting/modifying the 'security.evm' HMAC value directly. Signed-off-by: Mimi Zohar Signed-off-by: Greg Kroah-Hartman

ima: introduce ima_kernel_read()

2014-06-26T19:15:38Z

commit 0430e49b6e7c6b5e076be8fefdee089958c9adad upstream. Commit 8aac62706 "move exit_task_namespaces() outside of exit_notify" introduced the kernel opps since the kernel v3.10, which happens when Apparmor and IMA-appraisal are enabled at the same time. ---------------------------------------------------------------------- [ 106.750167] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 [ 106.750221] IP: [] our_mnt+0x1a/0x30 [ 106.750241] PGD 0 [ 106.750254] Oops: 0000 [#1] SMP [ 106.750272] Modules linked in: cuse parport_pc ppdev bnep rfcomm bluetooth rpcsec_gss_krb5 nfsd auth_rpcgss nfs_acl nfs lockd sunrpc fscache dm_crypt intel_rapl x86_pkg_temp_thermal intel_powerclamp kvm_intel snd_hda_codec_hdmi kvm crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 glue_helper lrw gf128mul ablk_helper cryptd snd_hda_codec_realtek dcdbas snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_page_alloc snd_seq_midi snd_seq_midi_event snd_rawmidi psmouse snd_seq microcode serio_raw snd_timer snd_seq_device snd soundcore video lpc_ich coretemp mac_hid lp parport mei_me mei nbd hid_generic e1000e usbhid ahci ptp hid libahci pps_core [ 106.750658] CPU: 6 PID: 1394 Comm: mysqld Not tainted 3.13.0-rc7-kds+ #15 [ 106.750673] Hardware name: Dell Inc. OptiPlex 9010/0M9KCM, BIOS A08 09/19/2012 [ 106.750689] task: ffff8800de804920 ti: ffff880400fca000 task.ti: ffff880400fca000 [ 106.750704] RIP: 0010:[] [] our_mnt+0x1a/0x30 [ 106.750725] RSP: 0018:ffff880400fcba60 EFLAGS: 00010286 [ 106.750738] RAX: 0000000000000000 RBX: 0000000000000100 RCX: ffff8800d51523e7 [ 106.750764] RDX: ffffffffffffffea RSI: ffff880400fcba34 RDI: ffff880402d20020 [ 106.750791] RBP: ffff880400fcbae0 R08: 0000000000000000 R09: 0000000000000001 [ 106.750817] R10: 0000000000000000 R11: 0000000000000001 R12: ffff8800d5152300 [ 106.750844] R13: ffff8803eb8df510 R14: ffff880400fcbb28 R15: ffff8800d51523e7 [ 106.750871] FS: 0000000000000000(0000) GS:ffff88040d200000(0000) knlGS:0000000000000000 [ 106.750910] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 106.750935] CR2: 0000000000000018 CR3: 0000000001c0e000 CR4: 00000000001407e0 [ 106.750962] Stack: [ 106.750981] ffffffff813434eb ffff880400fcbb20 ffff880400fcbb18 0000000000000000 [ 106.751037] ffff8800de804920 ffffffff8101b9b9 0001800000000000 0000000000000100 [ 106.751093] 0000010000000000 0000000000000002 000000000000000e ffff8803eb8df500 [ 106.751149] Call Trace: [ 106.751172] [] ? aa_path_name+0x2ab/0x430 [ 106.751199] [] ? sched_clock+0x9/0x10 [ 106.751225] [] aa_path_perm+0x7d/0x170 [ 106.751250] [] ? native_sched_clock+0x15/0x80 [ 106.751276] [] aa_file_perm+0x33/0x40 [ 106.751301] [] common_file_perm+0x8e/0xb0 [ 106.751327] [] apparmor_file_permission+0x18/0x20 [ 106.751355] [] security_file_permission+0x23/0xa0 [ 106.751382] [] rw_verify_area+0x52/0xe0 [ 106.751407] [] vfs_read+0x6d/0x170 [ 106.751432] [] kernel_read+0x41/0x60 [ 106.751457] [] ima_calc_file_hash+0x225/0x280 [ 106.751483] [] ? ima_calc_file_hash+0x32/0x280 [ 106.751509] [] ima_collect_measurement+0x9d/0x160 [ 106.751536] [] ? trace_hardirqs_on+0xd/0x10 [ 106.751562] [] ? ima_file_free+0x6c/0xd0 [ 106.751587] [] ima_update_xattr+0x34/0x60 [ 106.751612] [] ima_file_free+0xc0/0xd0 [ 106.751637] [] __fput+0xd5/0x300 [ 106.751662] [] ____fput+0xe/0x10 [ 106.751687] [] task_work_run+0xc4/0xe0 [ 106.751712] [] do_exit+0x2bd/0xa90 [ 106.751738] [] ? retint_swapgs+0x13/0x1b [ 106.751763] [] do_group_exit+0x4c/0xc0 [ 106.751788] [] SyS_exit_group+0x14/0x20 [ 106.751814] [] system_call_fastpath+0x1a/0x1f [ 106.751839] Code: c3 0f 1f 44 00 00 55 48 89 e5 e8 22 fe ff ff 5d c3 0f 1f 44 00 00 55 65 48 8b 04 25 c0 c9 00 00 48 8b 80 28 06 00 00 48 89 e5 5d <48> 8b 40 18 48 39 87 c0 00 00 00 0f 94 c0 c3 0f 1f 80 00 00 00 [ 106.752185] RIP [] our_mnt+0x1a/0x30 [ 106.752214] RSP [ 106.752236] CR2: 0000000000000018 [ 106.752258] ---[ end trace 3c520748b4732721 ]--- ---------------------------------------------------------------------- The reason for the oops is that IMA-appraisal uses "kernel_read()" when file is closed. kernel_read() honors LSM security hook which calls Apparmor handler, which uses current->nsproxy->mnt_ns. The 'guilty' commit changed the order of cleanup code so that nsproxy->mnt_ns was not already available for Apparmor. Discussion about the issue with Al Viro and Eric W. Biederman suggested that kernel_read() is too high-level for IMA. Another issue, except security checking, that was identified is mandatory locking. kernel_read honors it as well and it might prevent IMA from calculating necessary hash. It was suggested to use simplified version of the function without security and locking checks. This patch introduces special version ima_kernel_read(), which skips security and mandatory locking checking. It prevents the kernel oops to happen. Signed-off-by: Dmitry Kasatkin Suggested-by: Eric W. Biederman Signed-off-by: Mimi Zohar Signed-off-by: Greg Kroah-Hartman

ima: audit log files opened with O_DIRECT flag

2014-06-26T19:15:38Z

commit f9b2a735bdddf836214b5dca74f6ca7712e5a08c upstream. Files are measured or appraised based on the IMA policy. When a file, in policy, is opened with the O_DIRECT flag, a deadlock occurs. The first attempt at resolving this lockdep temporarily removed the O_DIRECT flag and restored it, after calculating the hash. The second attempt introduced the O_DIRECT_HAVELOCK flag. Based on this flag, do_blockdev_direct_IO() would skip taking the i_mutex a second time. The third attempt, by Dmitry Kasatkin, resolves the i_mutex locking issue, by re-introducing the IMA mutex, but uncovered another problem. Reading a file with O_DIRECT flag set, writes directly to userspace pages. A second patch allocates a user-space like memory. This works for all IMA hooks, except ima_file_free(), which is called on __fput() to recalculate the file hash. Until this last issue is addressed, do not 'collect' the measurement for measuring, appraising, or auditing files opened with the O_DIRECT flag set. Based on policy, permit or deny file access. This patch defines a new IMA policy rule option named 'permit_directio'. Policy rules could be defined, based on LSM or other criteria, to permit specific applications to open files with the O_DIRECT flag set. Changelog v1: - permit or deny file access based IMA policy rules Signed-off-by: Mimi Zohar Acked-by: Dmitry Kasatkin Signed-off-by: Greg Kroah-Hartman

device_cgroup: check if exception removal is allowed

2014-06-07T17:28:19Z

commit d2c2b11cfa134f4fbdcc34088824da26a084d8de upstream. [PATCH v3 1/2] device_cgroup: check if exception removal is allowed When the device cgroup hierarchy was introduced in bd2953ebbb53 - devcg: propagate local changes down the hierarchy a specific case was overlooked. Consider the hierarchy bellow: A default policy: ALLOW, exceptions will deny access \ B default policy: ALLOW, exceptions will deny access There's no need to verify when an new exception is added to B because in this case exceptions will deny access to further devices, which is always fine. Hierarchy in device cgroup only makes sure B won't have more access than A. But when an exception is removed (by writing devices.allow), it isn't checked if the user is in fact removing an inherited exception from A, thus giving more access to B. Example: # echo 'a' >A/devices.allow # echo 'c 1:3 rw' >A/devices.deny # echo $$ >A/B/tasks # echo >/dev/null -bash: /dev/null: Operation not permitted # echo 'c 1:3 w' >A/B/devices.allow # echo >/dev/null # This shouldn't be allowed and this patch fixes it by making sure to never allow exceptions in this case to be removed if the exception is partially or fully present on the parent. v3: missing '*' in function description v2: improved log message and formatting fixes Cc: cgroups@vger.kernel.org Cc: Li Zefan Signed-off-by: Aristeu Rozanski Acked-by: Serge Hallyn Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

device_cgroup: rework device access check and exception checking

2014-06-07T17:28:19Z

commit 79d719749d23234e9b725098aa49133f3ef7299d upstream. Whenever a device file is opened and checked against current device cgroup rules, it uses the same function (may_access()) as when a new exception rule is added by writing devices.{allow,deny}. And in both cases, the algorithm is the same, doesn't matter the behavior. First problem is having device access to be considered the same as rule checking. Consider the following structure: A (default behavior: allow, exceptions disallow access) \ B (default behavior: allow, exceptions disallow access) A new exception is added to B by writing devices.deny: c 12:34 rw When checking if that exception is allowed in may_access(): if (dev_cgroup->behavior == DEVCG_DEFAULT_ALLOW) { if (behavior == DEVCG_DEFAULT_ALLOW) { /* the exception will deny access to certain devices */ return true; Which is ok, since B is not getting more privileges than A, it doesn't matter and the rule is accepted Now, consider it's a device file open check and the process belongs to cgroup B. The access will be generated as: behavior: allow exception: c 12:34 rw The very same chunk of code will allow it, even if there's an explicit exception telling to do otherwise. A simple test case: # mkdir new_group # cd new_group # echo $$ >tasks # echo "c 1:3 w" >devices.deny # echo >/dev/null # echo $? 0 This is a serious bug and was introduced on c39a2a3018f8 devcg: prepare may_access() for hierarchy support To solve this problem, the device file open function was split from the new exception check. Second problem is how exceptions are processed by may_access(). The first part of the said function tries to match fully with an existing exception: list_for_each_entry_rcu(ex, &dev_cgroup->exceptions, list) { if ((refex->type & DEV_BLOCK) && !(ex->type & DEV_BLOCK)) continue; if ((refex->type & DEV_CHAR) && !(ex->type & DEV_CHAR)) continue; if (ex->major != ~0 && ex->major != refex->major) continue; if (ex->minor != ~0 && ex->minor != refex->minor) continue; if (refex->access & (~ex->access)) continue; match = true; break; } That means the new exception should be contained into an existing one to be considered a match: New exception Existing match? notes b 12:34 rwm b 12:34 rwm yes b 12:34 r b *:34 rw yes b 12:34 rw b 12:34 w no extra "r" b *:34 rw b 12:34 rw no too broad "*" b *:34 rw b *:34 rwm yes Which is fine in some cases. Consider: A (default behavior: deny, exceptions allow access) \ B (default behavior: deny, exceptions allow access) In this case the full match makes sense, the new exception cannot add more access than the parent allows But this doesn't always work, consider: A (default behavior: allow, exceptions disallow access) \ B (default behavior: deny, exceptions allow access) In this case, a new exception in B shouldn't match any of the exceptions in A, after all you can't allow something that was forbidden by A. But consider this scenario: New exception Existing in A match? outcome b 12:34 rw b 12:34 r no exception is accepted Because the new exception has "w" as extra, it doesn't match, so it'll be added to B's exception list. The same problem can happen during a file access check. Consider a cgroup with allow as default behavior: Access Exception match? b 12:34 rw b 12:34 r no In this case, the access didn't match any of the exceptions in the cgroup, which is required since exceptions will disallow access. To solve this problem, two new functions were created to match an exception either fully or partially. In the example above, a partial check will be performed and it'll produce a match since at least "b 12:34 r" from "b 12:34 rw" access matches. Cc: cgroups@vger.kernel.org Cc: Tejun Heo Cc: Serge Hallyn Cc: Li Zefan Signed-off-by: Aristeu Rozanski Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

ima: restore the original behavior for sending data with ima template

2014-04-27T00:19:04Z

commit c019e307ad82a8ee652b8ccbacf69ae94263b07b upstream. With the new template mechanism introduced in IMA since kernel 3.13, the format of data sent through the binary_runtime_measurements interface is slightly changed. Now, for a generic measurement, the format of template data (after the template name) is: template_len | field1_len | field1 | ... | fieldN_len | fieldN In addition, fields containing a string now include the '\0' termination character. Instead, the format for the 'ima' template should be: SHA1 digest | event name length | event name It must be noted that while in the IMA 3.13 code 'event name length' is 'IMA_EVENT_NAME_LEN_MAX + 1' (256 bytes), so that the template digest is calculated correctly, and 'event name' contains '\0', in the pre 3.13 code 'event name length' is exactly the string length and 'event name' does not contain the termination character. The patch restores the behavior of the IMA code pre 3.13 for the 'ima' template so that legacy userspace tools obtain a consistent behavior when receiving data from the binary_runtime_measurements interface regardless of which kernel version is used. Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar Signed-off-by: Greg Kroah-Hartman

selinux: correctly label /proc inodes in use before the policy is loaded

2014-04-14T13:50:02Z

commit f64410ec665479d7b4b77b7519e814253ed0f686 upstream. This patch is based on an earlier patch by Eric Paris, he describes the problem below: "If an inode is accessed before policy load it will get placed on a list of inodes to be initialized after policy load. After policy load we call inode_doinit() which calls inode_doinit_with_dentry() on all inodes accessed before policy load. In the case of inodes in procfs that means we'll end up at the bottom where it does: /* Default to the fs superblock SID. */ isec->sid = sbsec->sid; if ((sbsec->flags & SE_SBPROC) && !S_ISLNK(inode->i_mode)) { if (opt_dentry) { isec->sclass = inode_mode_to_security_class(...) rc = selinux_proc_get_sid(opt_dentry, isec->sclass, &sid); if (rc) goto out_unlock; isec->sid = sid; } } Since opt_dentry is null, we'll never call selinux_proc_get_sid() and will leave the inode labeled with the label on the superblock. I believe a fix would be to mimic the behavior of xattrs. Look for an alias of the inode. If it can't be found, just leave the inode uninitialized (and pick it up later) if it can be found, we should be able to call selinux_proc_get_sid() ..." On a system exhibiting this problem, you will notice a lot of files in /proc with the generic "proc_t" type (at least the ones that were accessed early in the boot), for example: # ls -Z /proc/sys/kernel/shmmax | awk '{ print $4 " " $5 }' system_u:object_r:proc_t:s0 /proc/sys/kernel/shmmax However, with this patch in place we see the expected result: # ls -Z /proc/sys/kernel/shmmax | awk '{ print $4 " " $5 }' system_u:object_r:sysctl_kernel_t:s0 /proc/sys/kernel/shmmax Cc: Eric Paris Signed-off-by: Paul Moore Acked-by: Eric Paris Signed-off-by: Greg Kroah-Hartman

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec

2014-03-18T16:42:33Z

Steffen Klassert says: ==================== 1) Fix a sleep in atomic when pfkey_sadb2xfrm_user_sec_ctx() is called from pfkey_compile_policy(). Fix from Nikolay Aleksandrov. 2) security_xfrm_policy_alloc() can be called in process and atomic context. Add an argument to let the callers choose the appropriate way. Fix from Nikolay Aleksandrov. ==================== Signed-off-by: David S. Miller

selinux: add gfp argument to security_xfrm_policy_alloc and fix callers

2014-03-10T07:30:02Z

security_xfrm_policy_alloc can be called in atomic context so the allocation should be done with GFP_ATOMIC. Add an argument to let the callers choose the appropriate way. In order to do so a gfp argument needs to be added to the method xfrm_policy_alloc_security in struct security_operations and to the internal function selinux_xfrm_alloc_user. After that switch to GFP_ATOMIC in the atomic callers and leave GFP_KERNEL as before for the rest. The path that needed the gfp argument addition is: security_xfrm_policy_alloc -> security_ops.xfrm_policy_alloc_security -> all users of xfrm_policy_alloc_security (e.g. selinux_xfrm_policy_alloc) -> selinux_xfrm_alloc_user (here the allocation used to be GFP_KERNEL only) Now adding a gfp argument to selinux_xfrm_alloc_user requires us to also add it to security_context_to_sid which is used inside and prior to this patch did only GFP_KERNEL allocation. So add gfp argument to security_context_to_sid and adjust all of its callers as well. CC: Paul Moore CC: Dave Jones CC: Steffen Klassert CC: Fan Du CC: David S. Miller CC: LSM list CC: SELinux list Signed-off-by: Nikolay Aleksandrov Acked-by: Paul Moore Signed-off-by: Steffen Klassert

KEYS: Make the keyring cycle detector ignore other keyrings of the same name

2014-03-10T01:57:18Z

This fixes CVE-2014-0102. The following command sequence produces an oops: keyctl new_session i=`keyctl newring _ses @s` keyctl link @s $i The problem is that search_nested_keyrings() sees two keyrings that have matching type and description, so keyring_compare_object() returns true. s_n_k() then passes the key to the iterator function - keyring_detect_cycle_iterator() - which *should* check to see whether this is the keyring of interest, not just one with the same name. Because assoc_array_find() will return one and only one match, I assumed that the iterator function would only see an exact match or never be called - but the iterator isn't only called from assoc_array_find()... The oops looks something like this: kernel BUG at /data/fs/linux-2.6-fscache/security/keys/keyring.c:1003! invalid opcode: 0000 [#1] SMP ... RIP: keyring_detect_cycle_iterator+0xe/0x1f ... Call Trace: search_nested_keyrings+0x76/0x2aa __key_link_check_live_key+0x50/0x5f key_link+0x4e/0x85 keyctl_keyring_link+0x60/0x81 SyS_keyctl+0x65/0xe4 tracesys+0xdd/0xe2 The fix is to make keyring_detect_cycle_iterator() check that the key it has is the key it was actually looking for rather than calling BUG_ON(). A testcase has been included in the keyutils testsuite for this: http://git.kernel.org/cgit/linux/kernel/git/dhowells/keyutils.git/commit/?id=891f3365d07f1996778ade0e3428f01878a1790b Reported-by: Tommi Rantala Signed-off-by: David Howells Acked-by: James Morris Signed-off-by: Linus Torvalds