user/sven/linux.git/security, branch v4.9.36

KEYS: encrypted: avoid encrypting/decrypting stack buffers

2017-06-14T13:05:55Z

commit e9ff56ac352446f55141aaef1553cee662b2e310 upstream. Since v4.9, the crypto API cannot (normally) be used to encrypt/decrypt stack buffers because the stack may be virtually mapped. Fix this for the padding buffers in encrypted-keys by using ZERO_PAGE for the encryption padding and by allocating a temporary heap buffer for the decryption padding. Tested with CONFIG_DEBUG_SG=y: keyctl new_session keyctl add user master "abcdefghijklmnop" @s keyid=$(keyctl add encrypted desc "new user:master 25" @s) datablob="$(keyctl pipe $keyid)" keyctl unlink $keyid keyid=$(keyctl add encrypted desc "load $datablob" @s) datablob2="$(keyctl pipe $keyid)" [ "$datablob" = "$datablob2" ] && echo "Success!" Cc: Andy Lutomirski Cc: Herbert Xu Cc: Mimi Zohar Signed-off-by: Eric Biggers Signed-off-by: David Howells Signed-off-by: James Morris Signed-off-by: Greg Kroah-Hartman

KEYS: fix freeing uninitialized memory in key_update()

2017-06-14T13:05:54Z

commit 63a0b0509e700717a59f049ec6e4e04e903c7fe2 upstream. key_update() freed the key_preparsed_payload even if it was not initialized first. This would cause a crash if userspace called keyctl_update() on a key with type like "asymmetric" that has a ->preparse() method but not an ->update() method. Possibly it could even be triggered for other key types by racing with keyctl_setperm() to make the KEY_NEED_WRITE check fail (the permission was already checked, so normally it wouldn't fail there). Reproducer with key type "asymmetric", given a valid cert.der: keyctl new_session keyid=$(keyctl padd asymmetric desc @s < cert.der) keyctl setperm $keyid 0x3f000000 keyctl update $keyid data [ 150.686666] BUG: unable to handle kernel NULL pointer dereference at 0000000000000001 [ 150.687601] IP: asymmetric_key_free_kids+0x12/0x30 [ 150.688139] PGD 38a3d067 [ 150.688141] PUD 3b3de067 [ 150.688447] PMD 0 [ 150.688745] [ 150.689160] Oops: 0000 [#1] SMP [ 150.689455] Modules linked in: [ 150.689769] CPU: 1 PID: 2478 Comm: keyctl Not tainted 4.11.0-rc4-xfstests-00187-ga9f6b6b8cd2f #742 [ 150.690916] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-20170228_101828-anatol 04/01/2014 [ 150.692199] task: ffff88003b30c480 task.stack: ffffc90000350000 [ 150.692952] RIP: 0010:asymmetric_key_free_kids+0x12/0x30 [ 150.693556] RSP: 0018:ffffc90000353e58 EFLAGS: 00010202 [ 150.694142] RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000004 [ 150.694845] RDX: ffffffff81ee3920 RSI: ffff88003d4b0700 RDI: 0000000000000001 [ 150.697569] RBP: ffffc90000353e60 R08: ffff88003d5d2140 R09: 0000000000000000 [ 150.702483] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 150.707393] R13: 0000000000000004 R14: ffff880038a4d2d8 R15: 000000000040411f [ 150.709720] FS: 00007fcbcee35700(0000) GS:ffff88003fd00000(0000) knlGS:0000000000000000 [ 150.711504] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 150.712733] CR2: 0000000000000001 CR3: 0000000039eab000 CR4: 00000000003406e0 [ 150.714487] Call Trace: [ 150.714975] asymmetric_key_free_preparse+0x2f/0x40 [ 150.715907] key_update+0xf7/0x140 [ 150.716560] ? key_default_cmp+0x20/0x20 [ 150.717319] keyctl_update_key+0xb0/0xe0 [ 150.718066] SyS_keyctl+0x109/0x130 [ 150.718663] entry_SYSCALL_64_fastpath+0x1f/0xc2 [ 150.719440] RIP: 0033:0x7fcbce75ff19 [ 150.719926] RSP: 002b:00007ffd5d167088 EFLAGS: 00000206 ORIG_RAX: 00000000000000fa [ 150.720918] RAX: ffffffffffffffda RBX: 0000000000404d80 RCX: 00007fcbce75ff19 [ 150.721874] RDX: 00007ffd5d16785e RSI: 000000002866cd36 RDI: 0000000000000002 [ 150.722827] RBP: 0000000000000006 R08: 000000002866cd36 R09: 00007ffd5d16785e [ 150.723781] R10: 0000000000000004 R11: 0000000000000206 R12: 0000000000404d80 [ 150.724650] R13: 00007ffd5d16784d R14: 00007ffd5d167238 R15: 000000000040411f [ 150.725447] Code: 83 c4 08 31 c0 5b 41 5c 41 5d 41 5e 41 5f 5d c3 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 85 ff 74 23 55 48 89 e5 53 48 89 fb <48> 8b 3f e8 06 21 c5 ff 48 8b 7b 08 e8 fd 20 c5 ff 48 89 df e8 [ 150.727489] RIP: asymmetric_key_free_kids+0x12/0x30 RSP: ffffc90000353e58 [ 150.728117] CR2: 0000000000000001 [ 150.728430] ---[ end trace f7f8fe1da2d5ae8d ]--- Fixes: 4d8c0250b841 ("KEYS: Call ->free_preparse() even after ->preparse() returns an error") Signed-off-by: Eric Biggers Signed-off-by: David Howells Signed-off-by: James Morris Signed-off-by: Greg Kroah-Hartman

KEYS: fix dereferencing NULL payload with nonzero length

2017-06-14T13:05:54Z

commit 5649645d725c73df4302428ee4e02c869248b4c5 upstream. sys_add_key() and the KEYCTL_UPDATE operation of sys_keyctl() allowed a NULL payload with nonzero length to be passed to the key type's ->preparse(), ->instantiate(), and/or ->update() methods. Various key types including asymmetric, cifs.idmap, cifs.spnego, and pkcs7_test did not handle this case, allowing an unprivileged user to trivially cause a NULL pointer dereference (kernel oops) if one of these key types was present. Fix it by doing the copy_from_user() when 'plen' is nonzero rather than when '_payload' is non-NULL, causing the syscall to fail with EFAULT as expected when an invalid buffer is specified. Signed-off-by: Eric Biggers Signed-off-by: David Howells Signed-off-by: James Morris Signed-off-by: Greg Kroah-Hartman

ima: accept previously set IMA_NEW_FILE

2017-05-25T13:44:34Z

commit 1ac202e978e18f045006d75bd549612620c6ec3a upstream. Modifying the attributes of a file makes ima_inode_post_setattr reset the IMA cache flags. So if the file, which has just been created, is opened a second time before the first file descriptor is closed, verification fails since the security.ima xattr has not been written yet. We therefore have to look at the IMA_NEW_FILE even if the file already existed. With this patch there should no longer be an error when cat tries to open testfile: $ rm -f testfile $ ( echo test >&3 ; touch testfile ; cat testfile ) 3>testfile A file being new is no reason to accept that it is missing a digital signature demanded by the policy. Signed-off-by: Daniel Glöckner Signed-off-by: Mimi Zohar Signed-off-by: Greg Kroah-Hartman

KEYS: fix keyctl_set_reqkey_keyring() to not leak thread keyrings

2017-04-27T07:10:37Z

commit c9f838d104fed6f2f61d68164712e3204bf5271b upstream. This fixes CVE-2017-7472. Running the following program as an unprivileged user exhausts kernel memory by leaking thread keyrings: #include int main() { for (;;) keyctl_set_reqkey_keyring(KEY_REQKEY_DEFL_THREAD_KEYRING); } Fix it by only creating a new thread keyring if there wasn't one before. To make things more consistent, make install_thread_keyring_to_cred() and install_process_keyring_to_cred() both return 0 if the corresponding keyring is already present. Fixes: d84f4f992cbd ("CRED: Inaugurate COW credentials") Signed-off-by: Eric Biggers Signed-off-by: David Howells Signed-off-by: Greg Kroah-Hartman

KEYS: Change the name of the dead type to ".dead" to prevent user access

2017-04-27T07:10:37Z

commit c1644fe041ebaf6519f6809146a77c3ead9193af upstream. This fixes CVE-2017-6951. Userspace should not be able to do things with the "dead" key type as it doesn't have some of the helper functions set upon it that the kernel needs. Attempting to use it may cause the kernel to crash. Fix this by changing the name of the type to ".dead" so that it's rejected up front on userspace syscalls by key_get_type_from_user(). Though this doesn't seem to affect recent kernels, it does affect older ones, certainly those prior to: commit c06cfb08b88dfbe13be44a69ae2fdc3a7c902d81 Author: David Howells Date: Tue Sep 16 17:36:06 2014 +0100 KEYS: Remove key_type::match in favour of overriding default by match_preparse which went in before 3.18-rc1. Signed-off-by: David Howells Signed-off-by: Greg Kroah-Hartman

KEYS: Disallow keyrings beginning with '.' to be joined as session keyrings

2017-04-27T07:10:37Z

commit ee8f844e3c5a73b999edf733df1c529d6503ec2f upstream. This fixes CVE-2016-9604. Keyrings whose name begin with a '.' are special internal keyrings and so userspace isn't allowed to create keyrings by this name to prevent shadowing. However, the patch that added the guard didn't fix KEYCTL_JOIN_SESSION_KEYRING. Not only can that create dot-named keyrings, it can also subscribe to them as a session keyring if they grant SEARCH permission to the user. This, for example, allows a root process to set .builtin_trusted_keys as its session keyring, at which point it has full access because now the possessor permissions are added. This permits root to add extra public keys, thereby bypassing module verification. This also affects kexec and IMA. This can be tested by (as root): keyctl session .builtin_trusted_keys keyctl add user a a @s keyctl list @s which on my test box gives me: 2 keys in keyring: 180010936: ---lswrv 0 0 asymmetric: Build time autogenerated kernel key: ae3d4a31b82daa8e1a75b49dc2bba949fd992a05 801382539: --alswrv 0 0 user: a Fix this by rejecting names beginning with a '.' in the keyctl. Signed-off-by: David Howells Acked-by: Mimi Zohar cc: linux-ima-devel@lists.sourceforge.net Signed-off-by: Greg Kroah-Hartman

ima: fix ima_d_path() possible race with rename

2017-03-12T05:41:44Z

commit bc15ed663e7e53ee4dc3e60f8d09c93a0528c694 upstream. On failure to return a pathname from ima_d_path(), a pointer to dname is returned, which is subsequently used in the IMA measurement list, the IMA audit records, and other audit logging. Saving the pointer to dname for later use has the potential to race with rename. Intead of returning a pointer to dname on failure, this patch returns a pointer to a copy of the filename. Reported-by: Al Viro Signed-off-by: Mimi Zohar Signed-off-by: Greg Kroah-Hartman

selinux: fix off-by-one in setprocattr

2017-02-14T23:25:34Z

commit 0c461cb727d146c9ef2d3e86214f498b78b7d125 upstream. SELinux tries to support setting/clearing of /proc/pid/attr attributes from the shell by ignoring terminating newlines and treating an attribute value that begins with a NUL or newline as an attempt to clear the attribute. However, the test for clearing attributes has always been wrong; it has an off-by-one error, and this could further lead to reading past the end of the allocated buffer since commit bb646cdb12e75d82258c2f2e7746d5952d3e321a ("proc_pid_attr_write(): switch to memdup_user()"). Fix the off-by-one error. Even with this fix, setting and clearing /proc/pid/attr attributes from the shell is not straightforward since the interface does not support multiple write() calls (so shells that write the value and newline separately will set and then immediately clear the attribute, requiring use of echo -n to set the attribute), whereas trying to use echo -n "" to clear the attribute causes the shell to skip the write() call altogether since POSIX says that a zero-length write causes no side effects. Thus, one must use echo -n to set and echo without -n to clear, as in the following example: $ echo -n unconfined_u:object_r:user_home_t:s0 > /proc/$$/attr/fscreate $ cat /proc/$$/attr/fscreate unconfined_u:object_r:user_home_t:s0 $ echo "" > /proc/$$/attr/fscreate $ cat /proc/$$/attr/fscreate Note the use of /proc/$$ rather than /proc/self, as otherwise the cat command will read its own attribute value, not that of the shell. There are no users of this facility to my knowledge; possibly we should just get rid of it. UPDATE: Upon further investigation it appears that a local process with the process:setfscreate permission can cause a kernel panic as a result of this bug. This patch fixes CVE-2017-2618. Signed-off-by: Stephen Smalley [PM: added the update about CVE-2017-2618 to the commit description] Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman Signed-off-by: James Morris

ima: fix memory leak in ima_release_policy

2017-01-12T10:39:30Z

commit 9a11a18902bc3b904353063763d06480620245a6 upstream. When the "policy" securityfs file is opened for read, it is opened as a sequential file. However, when it is eventually released, there is no cleanup for the sequential file, therefore some memory is leaked. This patch adds a call to seq_release() in ima_release_policy() to clean up the memory when the file is opened for read. Fixes: 80eae209d63a IMA: allow reading back the current policy Reported-by: Colin Ian King Signed-off-by: Eric Richter Tested-by: Colin Ian King Signed-off-by: Mimi Zohar Signed-off-by: Greg Kroah-Hartman