user/sven/linux.git/security/keys, branch v3.2.73

KEYS: Fix crash when attempt to garbage collect an uninstantiated keyring

2015-11-17T15:54:47Z

commit f05819df10d7b09f6d1eb6f8534a8f68e5a4fe61 upstream. The following sequence of commands: i=`keyctl add user a a @s` keyctl request2 keyring foo bar @t keyctl unlink $i @s tries to invoke an upcall to instantiate a keyring if one doesn't already exist by that name within the user's keyring set. However, if the upcall fails, the code sets keyring->type_data.reject_error to -ENOKEY or some other error code. When the key is garbage collected, the key destroy function is called unconditionally and keyring_destroy() uses list_empty() on keyring->type_data.link - which is in a union with reject_error. Subsequently, the kernel tries to unlink the keyring from the keyring names list - which oopses like this: BUG: unable to handle kernel paging request at 00000000ffffff8a IP: [] keyring_destroy+0x3d/0x88 ... Workqueue: events key_garbage_collector ... RIP: 0010:[] keyring_destroy+0x3d/0x88 RSP: 0018:ffff88003e2f3d30 EFLAGS: 00010203 RAX: 00000000ffffff82 RBX: ffff88003bf1a900 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 000000003bfc6901 RDI: ffffffff81a73a40 RBP: ffff88003e2f3d38 R08: 0000000000000152 R09: 0000000000000000 R10: ffff88003e2f3c18 R11: 000000000000865b R12: ffff88003bf1a900 R13: 0000000000000000 R14: ffff88003bf1a908 R15: ffff88003e2f4000 ... CR2: 00000000ffffff8a CR3: 000000003e3ec000 CR4: 00000000000006f0 ... Call Trace: [] key_gc_unused_keys.constprop.1+0x5d/0x10f [] key_garbage_collector+0x1fa/0x351 [] process_one_work+0x28e/0x547 [] worker_thread+0x26e/0x361 [] ? rescuer_thread+0x2a8/0x2a8 [] kthread+0xf3/0xfb [] ? kthread_create_on_node+0x1c2/0x1c2 [] ret_from_fork+0x3f/0x70 [] ? kthread_create_on_node+0x1c2/0x1c2 Note the value in RAX. This is a 32-bit representation of -ENOKEY. The solution is to only call ->destroy() if the key was successfully instantiated. Reported-by: Dmitry Vyukov Signed-off-by: David Howells Tested-by: Dmitry Vyukov [carnil: Backported for 3.2: adjust context] Signed-off-by: Ben Hutchings

KEYS: Fix race between key destruction and finding a keyring by name

2015-11-17T15:54:46Z

commit 94c4554ba07adbdde396748ee7ae01e86cf2d8d7 upstream. There appears to be a race between: (1) key_gc_unused_keys() which frees key->security and then calls keyring_destroy() to unlink the name from the name list (2) find_keyring_by_name() which calls key_permission(), thus accessing key->security, on a key before checking to see whether the key usage is 0 (ie. the key is dead and might be cleaned up). Fix this by calling ->destroy() before cleaning up the core key data - including key->security. Reported-by: Petr Matousek Signed-off-by: David Howells [carnil: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings

KEYS: close race between key lookup and freeing

2015-02-20T00:49:41Z

commit a3a8784454692dd72e5d5d34dcdab17b4420e74c upstream. When a key is being garbage collected, it's key->user would get put before the ->destroy() callback is called, where the key is removed from it's respective tracking structures. This leaves a key hanging in a semi-invalid state which leaves a window open for a different task to try an access key->user. An example is find_keyring_by_name() which would dereference key->user for a key that is in the process of being garbage collected (where key->user was freed but ->destroy() wasn't called yet - so it's still present in the linked list). This would cause either a panic, or corrupt memory. Fixes CVE-2014-9529. Signed-off-by: Sasha Levin Signed-off-by: David Howells [bwh: Backported to 3.2: adjust indentation] Signed-off-by: Ben Hutchings

KEYS: Fix stale key registration at error path

2015-02-20T00:49:29Z

commit b26bdde5bb27f3f900e25a95e33a0c476c8c2c48 upstream. When loading encrypted-keys module, if the last check of aes_get_sizes() in init_encrypted() fails, the driver just returns an error without unregistering its key type. This results in the stale entry in the list. In addition to memory leaks, this leads to a kernel crash when registering a new key type later. This patch fixes the problem by swapping the calls of aes_get_sizes() and register_key_type(), and releasing resources properly at the error paths. Bugzilla: https://bugzilla.opensuse.org/show_bug.cgi?id=908163 Signed-off-by: Takashi Iwai Signed-off-by: Mimi Zohar Signed-off-by: Ben Hutchings

key: Fix resource leak

2013-04-10T02:20:08Z

commit a84a921978b7d56e0e4b87ffaca6367429b4d8ff upstream. On an error iov may still have been reallocated and need freeing Signed-off-by: Alan Cox Signed-off-by: David Howells Signed-off-by: Ben Hutchings

Fix: compat_rw_copy_check_uvector() misuse in aio, readv, writev, and security keys

2013-03-20T15:03:37Z

commit 8aec0f5d4137532de14e6554fd5dd201ff3a3c49 upstream. Looking at mm/process_vm_access.c:process_vm_rw() and comparing it to compat_process_vm_rw() shows that the compatibility code requires an explicit "access_ok()" check before calling compat_rw_copy_check_uvector(). The same difference seems to appear when we compare fs/read_write.c:do_readv_writev() to fs/compat.c:compat_do_readv_writev(). This subtle difference between the compat and non-compat requirements should probably be debated, as it seems to be error-prone. In fact, there are two others sites that use this function in the Linux kernel, and they both seem to get it wrong: Now shifting our attention to fs/aio.c, we see that aio_setup_iocb() also ends up calling compat_rw_copy_check_uvector() through aio_setup_vectored_rw(). Unfortunately, the access_ok() check appears to be missing. Same situation for security/keys/compat.c:compat_keyctl_instantiate_key_iov(). I propose that we add the access_ok() check directly into compat_rw_copy_check_uvector(), so callers don't have to worry about it, and it therefore makes the compat call code similar to its non-compat counterpart. Place the access_ok() check in the same location where copy_from_user() can trigger a -EFAULT error in the non-compat code, so the ABI behaviors are alike on both compat and non-compat. While we are here, fix compat_do_readv_writev() so it checks for compat_rw_copy_check_uvector() negative return values. And also, fix a memory leak in compat_keyctl_instantiate_key_iov() error handling. Acked-by: Linus Torvalds Acked-by: Al Viro Signed-off-by: Mathieu Desnoyers Signed-off-by: Linus Torvalds [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings

keys: fix race with concurrent install_user_keyrings()

2013-03-20T15:03:33Z

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: Ben Hutchings

encrypted-keys: module build fixes

2011-11-16T19:23:14Z

Encrypted keys are encrypted/decrypted using either a trusted or user-defined key type, which is referred to as the 'master' key. The master key may be of type trusted iff the trusted key is builtin or both the trusted key and encrypted keys are built as modules. This patch resolves the build dependency problem. - Use "masterkey-$(CONFIG_TRUSTED_KEYS)-$(CONFIG_ENCRYPTED_KEYS)" construct to encapsulate the above logic. (Suggested by Dimtry Kasatkin.) - Fixing the encrypted-keys Makefile, results in a module name change from encrypted.ko to encrypted-keys.ko. - Add module dependency for request_trusted_key() definition Signed-off-by: Mimi Zohar

encrypted-keys: fix error return code

2011-11-16T19:23:13Z

Fix request_master_key() error return code. Signed-off-by: Mimi Zohar

KEYS: Fix a NULL pointer deref in the user-defined key type

2011-11-16T00:32:38Z

Fix a NULL pointer deref in the user-defined key type whereby updating a negative key into a fully instantiated key will cause an oops to occur when the code attempts to free the non-existent old payload. This results in an oops that looks something like the following: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 IP: [] __call_rcu+0x11/0x13e PGD 3391d067 PUD 3894a067 PMD 0 Oops: 0002 [#1] SMP CPU 1 Pid: 4354, comm: keyctl Not tainted 3.1.0-fsdevel+ #1140 /DG965RY RIP: 0010:[] [] __call_rcu+0x11/0x13e RSP: 0018:ffff88003d591df8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000000000006e RDX: ffffffff8161d0c0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88003d591e18 R08: 0000000000000000 R09: ffffffff8152fa6c R10: 0000000000000000 R11: 0000000000000300 R12: ffff88003b8f9538 R13: ffffffff8161d0c0 R14: ffff88003b8f9d50 R15: ffff88003c69f908 FS: 00007f97eb18c720(0000) GS:ffff88003bd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 000000003d47a000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process keyctl (pid: 4354, threadinfo ffff88003d590000, task ffff88003c78a040) Stack: ffff88003e0ffde0 ffff88003b8f9538 0000000000000001 ffff88003b8f9d50 ffff88003d591e28 ffffffff810860f0 ffff88003d591e68 ffffffff8117bfea ffff88003d591e68 ffffffff00000000 ffff88003e0ffde1 ffff88003e0ffde0 Call Trace: [] call_rcu_sched+0x10/0x12 [] user_update+0x8d/0xa2 [] key_create_or_update+0x236/0x270 [] sys_add_key+0x123/0x17e [] system_call_fastpath+0x16/0x1b Signed-off-by: David Howells Acked-by: Jeff Layton Acked-by: Neil Horman Acked-by: Steve Dickson Acked-by: James Morris Cc: stable@kernel.org Signed-off-by: Linus Torvalds