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* security/keys: rewrite all of big_key cryptoJason A. Donenfeld2017-09-252-71/+60
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This started out as just replacing the use of crypto/rng with get_random_bytes_wait, so that we wouldn't use bad randomness at boot time. But, upon looking further, it appears that there were even deeper underlying cryptographic problems, and that this seems to have been committed with very little crypto review. So, I rewrote the whole thing, trying to keep to the conventions introduced by the previous author, to fix these cryptographic flaws. It makes no sense to seed crypto/rng at boot time and then keep using it like this, when in fact there's already get_random_bytes_wait, which can ensure there's enough entropy and be a much more standard way of generating keys. Since this sensitive material is being stored untrusted, using ECB and no authentication is simply not okay at all. I find it surprising and a bit horrifying that this code even made it past basic crypto review, which perhaps points to some larger issues. This patch moves from using AES-ECB to using AES-GCM. Since keys are uniquely generated each time, we can set the nonce to zero. There was also a race condition in which the same key would be reused at the same time in different threads. A mutex fixes this issue now. So, to summarize, this commit fixes the following vulnerabilities: * Low entropy key generation, allowing an attacker to potentially guess or predict keys. * Unauthenticated encryption, allowing an attacker to modify the cipher text in particular ways in order to manipulate the plaintext, which is is even more frightening considering the next point. * Use of ECB mode, allowing an attacker to trivially swap blocks or compare identical plaintext blocks. * Key re-use. * Faulty memory zeroing. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Reviewed-by: Eric Biggers <ebiggers3@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Kirill Marinushkin <k.marinushkin@gmail.com> Cc: security@kernel.org Cc: stable@vger.kernel.org
* security/keys: properly zero out sensitive key material in big_keyJason A. Donenfeld2017-09-251-6/+6
| | | | | | | | | | | | | Error paths forgot to zero out sensitive material, so this patch changes some kfrees into a kzfrees. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Eric Biggers <ebiggers3@gmail.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Kirill Marinushkin <k.marinushkin@gmail.com> Cc: security@kernel.org Cc: stable@vger.kernel.org
* KEYS: use kmemdup() in request_key_auth_new()Eric Biggers2017-09-251-3/+2
| | | | | | | kmemdup() is preferred to kmalloc() followed by memcpy(). Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com>
* KEYS: restrict /proc/keys by credentials at open timeEric Biggers2017-09-251-6/+2
| | | | | | | | | | | | | | When checking for permission to view keys whilst reading from /proc/keys, we should use the credentials with which the /proc/keys file was opened. This is because, in a classic type of exploit, it can be possible to bypass checks for the *current* credentials by passing the file descriptor to a suid program. Following commit 34dbbcdbf633 ("Make file credentials available to the seqfile interfaces") we can finally fix it. So let's do it. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com>
* KEYS: reset parent each time before searching key_user_treeEric Biggers2017-09-251-2/+2
| | | | | | | | | | | | | | | In key_user_lookup(), if there is no key_user for the given uid, we drop key_user_lock, allocate a new key_user, and search the tree again. But we failed to set 'parent' to NULL at the beginning of the second search. If the tree were to be empty for the second search, the insertion would be done with an invalid 'parent', scribbling over freed memory. Fortunately this can't actually happen currently because the tree always contains at least the root_key_user. But it still should be fixed to make the code more robust. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com>
* KEYS: prevent KEYCTL_READ on negative keyEric Biggers2017-09-251-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Because keyctl_read_key() looks up the key with no permissions requested, it may find a negatively instantiated key. If the key is also possessed, we went ahead and called ->read() on the key. But the key payload will actually contain the ->reject_error rather than the normal payload. Thus, the kernel oopses trying to read the user_key_payload from memory address (int)-ENOKEY = 0x00000000ffffff82. Fortunately the payload data is stored inline, so it shouldn't be possible to abuse this as an arbitrary memory read primitive... Reproducer: keyctl new_session keyctl request2 user desc '' @s keyctl read $(keyctl show | awk '/user: desc/ {print $1}') It causes a crash like the following: BUG: unable to handle kernel paging request at 00000000ffffff92 IP: user_read+0x33/0xa0 PGD 36a54067 P4D 36a54067 PUD 0 Oops: 0000 [#1] SMP CPU: 0 PID: 211 Comm: keyctl Not tainted 4.14.0-rc1 #337 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-20170228_101828-anatol 04/01/2014 task: ffff90aa3b74c3c0 task.stack: ffff9878c0478000 RIP: 0010:user_read+0x33/0xa0 RSP: 0018:ffff9878c047bee8 EFLAGS: 00010246 RAX: 0000000000000001 RBX: ffff90aa3d7da340 RCX: 0000000000000017 RDX: 0000000000000000 RSI: 00000000ffffff82 RDI: ffff90aa3d7da340 RBP: ffff9878c047bf00 R08: 00000024f95da94f R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f58ece69740(0000) GS:ffff90aa3e200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000ffffff92 CR3: 0000000036adc001 CR4: 00000000003606f0 Call Trace: keyctl_read_key+0xac/0xe0 SyS_keyctl+0x99/0x120 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x7f58ec787bb9 RSP: 002b:00007ffc8d401678 EFLAGS: 00000206 ORIG_RAX: 00000000000000fa RAX: ffffffffffffffda RBX: 00007ffc8d402800 RCX: 00007f58ec787bb9 RDX: 0000000000000000 RSI: 00000000174a63ac RDI: 000000000000000b RBP: 0000000000000004 R08: 00007ffc8d402809 R09: 0000000000000020 R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffc8d402800 R13: 00007ffc8d4016e0 R14: 0000000000000000 R15: 0000000000000000 Code: e5 41 55 49 89 f5 41 54 49 89 d4 53 48 89 fb e8 a4 b4 ad ff 85 c0 74 09 80 3d b9 4c 96 00 00 74 43 48 8b b3 20 01 00 00 4d 85 ed <0f> b7 5e 10 74 29 4d 85 e4 74 24 4c 39 e3 4c 89 e2 4c 89 ef 48 RIP: user_read+0x33/0xa0 RSP: ffff9878c047bee8 CR2: 00000000ffffff92 Fixes: 61ea0c0ba904 ("KEYS: Skip key state checks when checking for possession") Cc: <stable@vger.kernel.org> [v3.13+] Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com>
* KEYS: prevent creating a different user's keyringsEric Biggers2017-09-254-12/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | It was possible for an unprivileged user to create the user and user session keyrings for another user. For example: sudo -u '#3000' sh -c 'keyctl add keyring _uid.4000 "" @u keyctl add keyring _uid_ses.4000 "" @u sleep 15' & sleep 1 sudo -u '#4000' keyctl describe @u sudo -u '#4000' keyctl describe @us This is problematic because these "fake" keyrings won't have the right permissions. In particular, the user who created them first will own them and will have full access to them via the possessor permissions, which can be used to compromise the security of a user's keys: -4: alswrv-----v------------ 3000 0 keyring: _uid.4000 -5: alswrv-----v------------ 3000 0 keyring: _uid_ses.4000 Fix it by marking user and user session keyrings with a flag KEY_FLAG_UID_KEYRING. Then, when searching for a user or user session keyring by name, skip all keyrings that don't have the flag set. Fixes: 69664cf16af4 ("keys: don't generate user and user session keyrings unless they're accessed") Cc: <stable@vger.kernel.org> [v2.6.26+] Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com>
* KEYS: fix writing past end of user-supplied buffer in keyring_read()Eric Biggers2017-09-251-9/+5
| | | | | | | | | | | | | Userspace can call keyctl_read() on a keyring to get the list of IDs of keys in the keyring. But if the user-supplied buffer is too small, the kernel would write the full list anyway --- which will corrupt whatever userspace memory happened to be past the end of the buffer. Fix it by only filling the space that is available. Fixes: b2a4df200d57 ("KEYS: Expand the capacity of a keyring") Cc: <stable@vger.kernel.org> [v3.13+] Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com>
* KEYS: fix key refcount leak in keyctl_read_key()Eric Biggers2017-09-251-1/+1
| | | | | | | | | | | | | | In keyctl_read_key(), if key_permission() were to return an error code other than EACCES, we would leak a the reference to the key. This can't actually happen currently because key_permission() can only return an error code other than EACCES if security_key_permission() does, only SELinux and Smack implement that hook, and neither can return an error code other than EACCES. But it should still be fixed, as it is a bug waiting to happen. Fixes: 29db91906340 ("[PATCH] Keys: Add LSM hooks for key management [try #3]") Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com>
* KEYS: fix key refcount leak in keyctl_assume_authority()Eric Biggers2017-09-251-4/+2
| | | | | | | | | | | | | | | | | In keyctl_assume_authority(), if keyctl_change_reqkey_auth() were to fail, we would leak the reference to the 'authkey'. Currently this can only happen if prepare_creds() fails to allocate memory. But it still should be fixed, as it is a more severe bug waiting to happen. This patch also moves the read of 'authkey->serial' to before the reference to the authkey is dropped. Doing the read after dropping the reference is very fragile because it assumes we still hold another reference to the key. (Which we do, in current->cred->request_key_auth, but there's no reason not to write it in the "obviously correct" way.) Fixes: d84f4f992cbd ("CRED: Inaugurate COW credentials") Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com>
* KEYS: don't revoke uninstantiated key in request_key_auth_new()Eric Biggers2017-09-251-1/+0
| | | | | | | | | | | | | | | If key_instantiate_and_link() were to fail (which fortunately isn't possible currently), the call to key_revoke(authkey) would crash with a NULL pointer dereference in request_key_auth_revoke() because the key has not yet been instantiated. Fix this by removing the call to key_revoke(). key_put() is sufficient, as it's not possible for an uninstantiated authkey to have been used for anything yet. Fixes: b5f545c880a2 ("[PATCH] keys: Permit running process to instantiate keys") Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com>
* KEYS: fix cred refcount leak in request_key_auth_new()Eric Biggers2017-09-251-37/+31
| | | | | | | | | | | | | | In request_key_auth_new(), if key_alloc() or key_instantiate_and_link() were to fail, we would leak a reference to the 'struct cred'. Currently this can only happen if key_alloc() fails to allocate memory. But it still should be fixed, as it is a more severe bug waiting to happen. Fix it by cleaning things up to use a helper function which frees a 'struct request_key_auth' correctly. Fixes: d84f4f992cbd ("CRED: Inaugurate COW credentials") Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com>
* fs: fix kernel_write prototypeChristoph Hellwig2017-09-041-1/+2
| | | | | | | | Make the position an in/out argument like all the other read/write helpers and and make the buf argument a void pointer. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs: fix kernel_read prototypeChristoph Hellwig2017-09-041-1/+2
| | | | | | | | | | Use proper ssize_t and size_t types for the return value and count argument, move the offset last and make it an in/out argument like all other read/write helpers, and make the buf argument a void pointer to get rid of lots of casts in the callers. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge tag 'gcc-plugins-v4.13-rc2' of ↵Linus Torvalds2017-07-191-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull structure randomization updates from Kees Cook: "Now that IPC and other changes have landed, enable manual markings for randstruct plugin, including the task_struct. This is the rest of what was staged in -next for the gcc-plugins, and comes in three patches, largest first: - mark "easy" structs with __randomize_layout - mark task_struct with an optional anonymous struct to isolate the __randomize_layout section - mark structs to opt _out_ of automated marking (which will come later) And, FWIW, this continues to pass allmodconfig (normal and patched to enable gcc-plugins) builds of x86_64, i386, arm64, arm, powerpc, and s390 for me" * tag 'gcc-plugins-v4.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: randstruct: opt-out externally exposed function pointer structs task_struct: Allow randomized layout randstruct: Mark various structs for randomization
| * randstruct: Mark various structs for randomizationKees Cook2017-06-301-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This marks many critical kernel structures for randomization. These are structures that have been targeted in the past in security exploits, or contain functions pointers, pointers to function pointer tables, lists, workqueues, ref-counters, credentials, permissions, or are otherwise sensitive. This initial list was extracted from Brad Spengler/PaX Team's code in the last public patch of grsecurity/PaX based on my understanding of the code. Changes or omissions from the original code are mine and don't reflect the original grsecurity/PaX code. Left out of this list is task_struct, which requires special handling and will be covered in a subsequent patch. Signed-off-by: Kees Cook <keescook@chromium.org>
* | KEYS: DH: validate __spare fieldEric Biggers2017-07-142-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | Syscalls must validate that their reserved arguments are zero and return EINVAL otherwise. Otherwise, it will be impossible to actually use them for anything in the future because existing programs may be passing garbage in. This is standard practice when adding new APIs. Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | Merge tag 'docs-4.13' of git://git.lwn.net/linuxLinus Torvalds2017-07-035-5/+5
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull documentation updates from Jonathan Corbet: "There has been a fair amount of activity in the docs tree this time around. Highlights include: - Conversion of a bunch of security documentation into RST - The conversion of the remaining DocBook templates by The Amazing Mauro Machine. We can now drop the entire DocBook build chain. - The usual collection of fixes and minor updates" * tag 'docs-4.13' of git://git.lwn.net/linux: (90 commits) scripts/kernel-doc: handle DECLARE_HASHTABLE Documentation: atomic_ops.txt is core-api/atomic_ops.rst Docs: clean up some DocBook loose ends Make the main documentation title less Geocities Docs: Use kernel-figure in vidioc-g-selection.rst Docs: fix table problems in ras.rst Docs: Fix breakage with Sphinx 1.5 and upper Docs: Include the Latex "ifthen" package doc/kokr/howto: Only send regression fixes after -rc1 docs-rst: fix broken links to dynamic-debug-howto in kernel-parameters doc: Document suitability of IBM Verse for kernel development Doc: fix a markup error in coding-style.rst docs: driver-api: i2c: remove some outdated information Documentation: DMA API: fix a typo in a function name Docs: Insert missing space to separate link from text doc/ko_KR/memory-barriers: Update control-dependencies example Documentation, kbuild: fix typo "minimun" -> "minimum" docs: Fix some formatting issues in request-key.rst doc: ReSTify keys-trusted-encrypted.txt doc: ReSTify keys-request-key.txt ...
| * | doc: ReSTify keys-trusted-encrypted.txtKees Cook2017-05-183-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | Adjusts for ReST markup and moves under keys security devel index. Cc: David Howells <dhowells@redhat.com> Cc: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
| * | doc: ReSTify keys-request-key.txtKees Cook2017-05-182-2/+2
| |/ | | | | | | | | | | | | | | Adjusts for ReST markup and moves under keys security devel index. Cc: David Howells <dhowells@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* | sched/wait: Split out the wait_bit*() APIs from <linux/wait.h> into ↵Ingo Molnar2017-06-201-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | <linux/wait_bit.h> The wait_bit*() types and APIs are mixed into wait.h, but they are a pretty orthogonal extension of wait-queues. Furthermore, only about 50 kernel files use these APIs, while over 1000 use the regular wait-queue functionality. So clean up the main wait.h by moving the wait-bit functionality out of it, into a separate .h and .c file: include/linux/wait_bit.h for types and APIs kernel/sched/wait_bit.c for the implementation Update all header dependencies. This reduces the size of wait.h rather significantly, by about 30%. Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | KEYS: fix refcount_inc() on zeroMark Rutland2017-06-091-7/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a key's refcount is dropped to zero between key_lookup() peeking at the refcount and subsequently attempting to increment it, refcount_inc() will see a zero refcount. Here, refcount_inc() will WARN_ONCE(), and will *not* increment the refcount, which will remain zero. Once key_lookup() drops key_serial_lock, it is possible for the key to be freed behind our back. This patch uses refcount_inc_not_zero() to perform the peek and increment atomically. Fixes: fff292914d3a2f1e ("security, keys: convert key.usage from atomic_t to refcount_t") Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: David Howells <dhowells@redhat.com> Cc: David Windsor <dwindsor@gmail.com> Cc: Elena Reshetova <elena.reshetova@intel.com> Cc: Hans Liljestrand <ishkamiel@gmail.com> Cc: James Morris <james.l.morris@oracle.com> Cc: Kees Cook <keescook@chromium.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | KEYS: Convert KEYCTL_DH_COMPUTE to use the crypto KPP APIMat Martineau2017-06-092-103/+171
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The initial Diffie-Hellman computation made direct use of the MPI library because the crypto module did not support DH at the time. Now that KPP is implemented, KEYCTL_DH_COMPUTE should use it to get rid of duplicate code and leverage possible hardware acceleration. This fixes an issue whereby the input to the KDF computation would include additional uninitialized memory when the result of the Diffie-Hellman computation was shorter than the input prime number. Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | KEYS: DH: ensure the KDF counter is properly alignedEric Biggers2017-06-091-13/+3
| | | | | | | | | | | | | | | | | | | | Accessing a 'u8[4]' through a '__be32 *' violates alignment rules. Just make the counter a __be32 instead. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | KEYS: DH: don't feed uninitialized "otherinfo" into KDFEric Biggers2017-06-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | If userspace called KEYCTL_DH_COMPUTE with kdf_params containing NULL otherinfo but nonzero otherinfolen, the kernel would allocate a buffer for the otherinfo, then feed it into the KDF without initializing it. Fix this by always doing the copy from userspace (which will fail with EFAULT in this scenario). Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | KEYS: DH: forbid using digest_null as the KDF hashEric Biggers2017-06-091-1/+11
| | | | | | | | | | | | | | | | | | | | | | Requesting "digest_null" in the keyctl_kdf_params caused an infinite loop in kdf_ctr() because the "null" hash has a digest size of 0. Fix it by rejecting hash algorithms with a digest size of 0. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | KEYS: sanitize key structs before freeingEric Biggers2017-06-091-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While a 'struct key' itself normally does not contain sensitive information, Documentation/security/keys.txt actually encourages this: "Having a payload is not required; and the payload can, in fact, just be a value stored in the struct key itself." In case someone has taken this advice, or will take this advice in the future, zero the key structure before freeing it. We might as well, and as a bonus this could make it a bit more difficult for an adversary to determine which keys have recently been in use. This is safe because the key_jar cache does not use a constructor. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | KEYS: trusted: sanitize all key materialEric Biggers2017-06-091-28/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | As the previous patch did for encrypted-keys, zero sensitive any potentially sensitive data related to the "trusted" key type before it is freed. Notably, we were not zeroing the tpm_buf structures in which the actual key is stored for TPM seal and unseal, nor were we zeroing the trusted_key_payload in certain error paths. Cc: Mimi Zohar <zohar@linux.vnet.ibm.com> Cc: David Safford <safford@us.ibm.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | KEYS: encrypted: sanitize all key materialEric Biggers2017-06-091-18/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For keys of type "encrypted", consistently zero sensitive key material before freeing it. This was already being done for the decrypted payloads of encrypted keys, but not for the master key and the keys derived from the master key. Out of an abundance of caution and because it is trivial to do so, also zero buffers containing the key payload in encrypted form, although depending on how the encrypted-keys feature is used such information does not necessarily need to be kept secret. Cc: Mimi Zohar <zohar@linux.vnet.ibm.com> Cc: David Safford <safford@us.ibm.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | KEYS: user_defined: sanitize key payloadsEric Biggers2017-06-091-4/+12
| | | | | | | | | | | | | | | | | | | | Zero the payloads of user and logon keys before freeing them. This prevents sensitive key material from being kept around in the slab caches after a key is released. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | KEYS: sanitize add_key() and keyctl() key payloadsEric Biggers2017-06-091-3/+9
| | | | | | | | | | | | | | | | | | | | | | Before returning from add_key() or one of the keyctl() commands that takes in a key payload, zero the temporary buffer that was allocated to hold the key payload copied from userspace. This may contain sensitive key material that should not be kept around in the slab caches. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | KEYS: fix freeing uninitialized memory in key_update()Eric Biggers2017-06-091-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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") Cc: stable@vger.kernel.org # 3.17+ Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | KEYS: fix dereferencing NULL payload with nonzero lengthEric Biggers2017-06-091-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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. Cc: stable@vger.kernel.org # 2.6.10+ Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | KEYS: encrypted: use constant-time HMAC comparisonEric Biggers2017-06-091-2/+3
| | | | | | | | | | | | | | | | | | | | | | MACs should, in general, be compared using crypto_memneq() to prevent timing attacks. Cc: Mimi Zohar <zohar@linux.vnet.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | KEYS: encrypted: fix race causing incorrect HMAC calculationsEric Biggers2017-06-091-83/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The encrypted-keys module was using a single global HMAC transform, which could be rekeyed by multiple threads concurrently operating on different keys, causing incorrect HMAC values to be calculated. Fix this by allocating a new HMAC transform whenever we need to calculate a HMAC. Also simplify things a bit by allocating the shash_desc's using SHASH_DESC_ON_STACK() for both the HMAC and unkeyed hashes. The following script reproduces the bug: keyctl new_session keyctl add user master "abcdefghijklmnop" @s for i in $(seq 2); do ( set -e for j in $(seq 1000); do keyid=$(keyctl add encrypted desc$i "new user:master 25" @s) datablob="$(keyctl pipe $keyid)" keyctl unlink $keyid > /dev/null keyid=$(keyctl add encrypted desc$i "load $datablob" @s) keyctl unlink $keyid > /dev/null done ) & done Output with bug: [ 439.691094] encrypted_key: bad hmac (-22) add_key: Invalid argument add_key: Invalid argument Cc: Mimi Zohar <zohar@linux.vnet.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | KEYS: encrypted: fix buffer overread in valid_master_desc()Eric Biggers2017-06-091-16/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | With the 'encrypted' key type it was possible for userspace to provide a data blob ending with a master key description shorter than expected, e.g. 'keyctl add encrypted desc "new x" @s'. When validating such a master key description, validate_master_desc() could read beyond the end of the buffer. Fix this by using strncmp() instead of memcmp(). [Also clean up the code to deduplicate some logic.] Cc: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | KEYS: encrypted: avoid encrypting/decrypting stack buffersEric Biggers2017-06-091-8/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since v4.9, the crypto API cannot (normally) be used to encrypt/decrypt stack buffers because the stack may be virtually mapped. Fix this for the padding buffers in encrypted-keys by using ZERO_PAGE for the encryption padding and by allocating a temporary heap buffer for the decryption padding. Tested with CONFIG_DEBUG_SG=y: keyctl new_session keyctl add user master "abcdefghijklmnop" @s keyid=$(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 <luto@kernel.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Mimi Zohar <zohar@linux.vnet.ibm.com> Cc: stable@vger.kernel.org # 4.9+ Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | KEYS: put keyring if install_session_keyring_to_cred() failsEric Biggers2017-06-091-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | In join_session_keyring(), if install_session_keyring_to_cred() were to fail, we would leak the keyring reference, just like in the bug fixed by commit 23567fd052a9 ("KEYS: Fix keyring ref leak in join_session_keyring()"). Fortunately this cannot happen currently, but we really should be more careful. Do this by adding and using a new error label at which the keyring reference is dropped. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | KEYS: Delete an error message for a failed memory allocation in ↵Markus Elfring2017-06-091-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | get_derived_key() Omit an extra message for a memory allocation failure in this function. This issue was detected by using the Coccinelle software. Link: http://events.linuxfoundation.org/sites/events/files/slides/LCJ16-Refactor_Strings-WSang_0.pdf Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | security: use READ_ONCE instead of deprecated ACCESS_ONCEDavidlohr Bueso2017-06-091-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the new standardized functions, we can replace all ACCESS_ONCE() calls across relevant security/keyrings/. ACCESS_ONCE() does not work reliably on non-scalar types. For example gcc 4.6 and 4.7 might remove the volatile tag for such accesses during the SRA (scalar replacement of aggregates) step: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 Update the new calls regardless of if it is a scalar type, this is cleaner than having three alternatives. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | security/keys: add CONFIG_KEYS_COMPAT to KconfigBilal Amarni2017-06-091-0/+4
|/ | | | | | | | | | | | | | | | | | | | | CONFIG_KEYS_COMPAT is defined in arch-specific Kconfigs and is missing for several 64-bit architectures : mips, parisc, tile. At the moment and for those architectures, calling in 32-bit userspace the keyctl syscall would return an ENOSYS error. This patch moves the CONFIG_KEYS_COMPAT option to security/keys/Kconfig, to make sure the compatibility wrapper is registered by default for any 64-bit architecture as long as it is configured with CONFIG_COMPAT. [DH: Modified to remove arm64 compat enablement also as requested by Eric Biggers] Signed-off-by: Bilal Amarni <bilal.amarni@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Arnd Bergmann <arnd@arndb.de> cc: Eric Biggers <ebiggers3@gmail.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
* treewide: use kv[mz]alloc* rather than opencoded variantsMichal Hocko2017-05-081-16/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are many code paths opencoding kvmalloc. Let's use the helper instead. The main difference to kvmalloc is that those users are usually not considering all the aspects of the memory allocator. E.g. allocation requests <= 32kB (with 4kB pages) are basically never failing and invoke OOM killer to satisfy the allocation. This sounds too disruptive for something that has a reasonable fallback - the vmalloc. On the other hand those requests might fallback to vmalloc even when the memory allocator would succeed after several more reclaim/compaction attempts previously. There is no guarantee something like that happens though. This patch converts many of those places to kv[mz]alloc* helpers because they are more conservative. Link: http://lkml.kernel.org/r/20170306103327.2766-2-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> # Xen bits Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Andreas Dilger <andreas.dilger@intel.com> # Lustre Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> # KVM/s390 Acked-by: Dan Williams <dan.j.williams@intel.com> # nvdim Acked-by: David Sterba <dsterba@suse.com> # btrfs Acked-by: Ilya Dryomov <idryomov@gmail.com> # Ceph Acked-by: Tariq Toukan <tariqt@mellanox.com> # mlx4 Acked-by: Leon Romanovsky <leonro@mellanox.com> # mlx5 Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Anton Vorontsov <anton@enomsg.org> Cc: Colin Cross <ccross@android.com> Cc: Tony Luck <tony.luck@intel.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Ben Skeggs <bskeggs@redhat.com> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Santosh Raspatur <santosh@chelsio.com> Cc: Hariprasad S <hariprasad@chelsio.com> Cc: Yishai Hadas <yishaih@mellanox.com> Cc: Oleg Drokin <oleg.drokin@intel.com> Cc: "Yan, Zheng" <zyan@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'next' of ↵Linus Torvalds2017-05-0313-63/+567
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull security subsystem updates from James Morris: "Highlights: IMA: - provide ">" and "<" operators for fowner/uid/euid rules KEYS: - add a system blacklist keyring - add KEYCTL_RESTRICT_KEYRING, exposes keyring link restriction functionality to userland via keyctl() LSM: - harden LSM API with __ro_after_init - add prlmit security hook, implement for SELinux - revive security_task_alloc hook TPM: - implement contextual TPM command 'spaces'" * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (98 commits) tpm: Fix reference count to main device tpm_tis: convert to using locality callbacks tpm: fix handling of the TPM 2.0 event logs tpm_crb: remove a cruft constant keys: select CONFIG_CRYPTO when selecting DH / KDF apparmor: Make path_max parameter readonly apparmor: fix parameters so that the permission test is bypassed at boot apparmor: fix invalid reference to index variable of iterator line 836 apparmor: use SHASH_DESC_ON_STACK security/apparmor/lsm.c: set debug messages apparmor: fix boolreturn.cocci warnings Smack: Use GFP_KERNEL for smk_netlbl_mls(). smack: fix double free in smack_parse_opts_str() KEYS: add SP800-56A KDF support for DH KEYS: Keyring asymmetric key restrict method with chaining KEYS: Restrict asymmetric key linkage using a specific keychain KEYS: Add a lookup_restriction function for the asymmetric key type KEYS: Add KEYCTL_RESTRICT_KEYRING KEYS: Consistent ordering for __key_link_begin and restrict check KEYS: Add an optional lookup_restriction hook to key_type ...
| * keys: select CONFIG_CRYPTO when selecting DH / KDFStephan Müller2017-04-111-0/+1
| | | | | | | | | | | | | | | | | | Select CONFIG_CRYPTO in addition to CONFIG_HASH to ensure that also CONFIG_HASH2 is selected. Both are needed for the shash cipher support required for the KDF operation. Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: David Howells <dhowells@redhat.com>
| * KEYS: add SP800-56A KDF support for DHStephan Mueller2017-04-047-18/+275
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | SP800-56A defines the use of DH with key derivation function based on a counter. The input to the KDF is defined as (DH shared secret || other information). The value for the "other information" is to be provided by the caller. The KDF is implemented using the hash support from the kernel crypto API. The implementation uses the symmetric hash support as the input to the hash operation is usually very small. The caller is allowed to specify the hash name that he wants to use to derive the key material allowing the use of all supported hashes provided with the kernel crypto API. As the KDF implements the proper truncation of the DH shared secret to the requested size, this patch fills the caller buffer up to its size. The patch is tested with a new test added to the keyutils user space code which uses a CAVS test vector testing the compliance with SP800-56A. Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: David Howells <dhowells@redhat.com>
| * KEYS: Add KEYCTL_RESTRICT_KEYRINGMat Martineau2017-04-044-0/+170
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Keyrings recently gained restrict_link capabilities that allow individual keys to be validated prior to linking. This functionality was only available using internal kernel APIs. With the KEYCTL_RESTRICT_KEYRING command existing keyrings can be configured to check the content of keys before they are linked, and then allow or disallow linkage of that key to the keyring. To restrict a keyring, call: keyctl(KEYCTL_RESTRICT_KEYRING, key_serial_t keyring, const char *type, const char *restriction) where 'type' is the name of a registered key type and 'restriction' is a string describing how key linkage is to be restricted. The restriction option syntax is specific to each key type. Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
| * KEYS: Consistent ordering for __key_link_begin and restrict checkMat Martineau2017-04-041-11/+13
| | | | | | | | | | | | | | | | | | | | | | | | The keyring restrict callback was sometimes called before __key_link_begin and sometimes after, which meant that the keyring semaphores were not always held during the restrict callback. If the semaphores are consistently acquired before checking link restrictions, keyring contents cannot be changed after the restrict check is complete but before the evaluated key is linked to the keyring. Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
| * KEYS: Use structure to capture key restriction function and dataMat Martineau2017-04-044-14/+90
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Replace struct key's restrict_link function pointer with a pointer to the new struct key_restriction. The structure contains pointers to the restriction function as well as relevant data for evaluating the restriction. The garbage collector checks restrict_link->keytype when key types are unregistered. Restrictions involving a removed key type are converted to use restrict_link_reject so that restrictions cannot be removed by unregistering key types. Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
| * KEYS: Split role of the keyring pointer for keyring restrict functionsMat Martineau2017-04-032-4/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The first argument to the restrict_link_func_t functions was a keyring pointer. These functions are called by the key subsystem with this argument set to the destination keyring, but restrict_link_by_signature expects a pointer to the relevant trusted keyring. Restrict functions may need something other than a single struct key pointer to allow or reject key linkage, so the data used to make that decision (such as the trust keyring) is moved to a new, fourth argument. The first argument is now always the destination keyring. Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
| * KEYS: Use a typedef for restrict_link function pointersMat Martineau2017-04-032-9/+3
| | | | | | | | | | | | | | This pointer type needs to be returned from a lookup function, and without a typedef the syntax gets cumbersome. Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
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