linux/security, branch v4.5

Merge branch 'stable-4.5' of git://git.infradead.org/users/pcmoore/selinux into for-linus

2016-02-26T08:32:16Z

selinux: Don't sleep inside inode_getsecid hook

2016-02-19T21:29:19Z

The inode_getsecid hook is called from contexts in which sleeping is not allowed, so we cannot revalidate inode security labels from there. Use the non-validating version of inode_security() instead. Reported-by: Benjamin Coddington Signed-off-by: Andreas Gruenbacher Acked-by: Stephen Smalley Signed-off-by: Paul Moore

EVM: Use crypto_memneq() for digest comparisons

2016-02-12T07:36:47Z

This patch fixes vulnerability CVE-2016-2085. The problem exists because the vm_verify_hmac() function includes a use of memcmp(). Unfortunately, this allows timing side channel attacks; specifically a MAC forgery complexity drop from 2^128 to 2^12. This patch changes the memcmp() to the cryptographically safe crypto_memneq(). Reported-by: Xiaofei Rex Guo Signed-off-by: Ryan Ware Cc: stable@vger.kernel.org Signed-off-by: Mimi Zohar Signed-off-by: James Morris

selinux: nlmsgtab: add SOCK_DESTROY to the netlink mapping tables

2016-02-09T09:55:05Z

Without this, using SOCK_DESTROY in enforcing mode results in: SELinux: unrecognized netlink message type=21 for sclass=32 Signed-off-by: Lorenzo Colitti Signed-off-by: David S. Miller

KEYS: Only apply KEY_FLAG_KEEP to a key if a parent keyring has it set

2016-01-27T23:48:40Z

KEY_FLAG_KEEP should only be applied to a key if the keyring it is being linked into has KEY_FLAG_KEEP set. To this end, partially revert the following patch: commit 1d6d167c2efcfe9539d9cffb1a1be9c92e39c2c0 Author: Mimi Zohar Date: Thu Jan 7 07:46:36 2016 -0500 KEYS: refcount bug fix to undo the change that made it unconditional (Mimi got it right the first time). Without undoing this change, it becomes impossible to delete, revoke or invalidate keys added to keyrings through __key_instantiate_and_link() where the keyring has itself been linked to. To test this, run the following command sequence: keyctl newring foo @s keyctl add user a a %:foo keyctl unlink %user:a %:foo keyctl clear %:foo With the commit mentioned above the third and fourth commands fail with EPERM when they should succeed. Reported-by: Stephen Gallager Signed-off-by: David Howells Acked-by: Mimi Zohar cc: Mimi Zohar cc: keyrings@vger.kernel.org cc: stable@vger.kernel.org Signed-off-by: James Morris

wrappers for ->i_mutex access

2016-01-22T23:04:28Z

parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested}, inode_foo(inode) being mutex_foo(&inode->i_mutex). Please, use those for access to ->i_mutex; over the coming cycle ->i_mutex will become rwsem, with ->lookup() done with it held only shared. Signed-off-by: Al Viro

ptrace: use fsuid, fsgid, effective creds for fs access checks

2016-01-21T01:09:18Z

By checking the effective credentials instead of the real UID / permitted capabilities, ensure that the calling process actually intended to use its credentials. To ensure that all ptrace checks use the correct caller credentials (e.g. in case out-of-tree code or newly added code omits the PTRACE_MODE_*CREDS flag), use two new flags and require one of them to be set. The problem was that when a privileged task had temporarily dropped its privileges, e.g. by calling setreuid(0, user_uid), with the intent to perform following syscalls with the credentials of a user, it still passed ptrace access checks that the user would not be able to pass. While an attacker should not be able to convince the privileged task to perform a ptrace() syscall, this is a problem because the ptrace access check is reused for things in procfs. In particular, the following somewhat interesting procfs entries only rely on ptrace access checks: /proc/$pid/stat - uses the check for determining whether pointers should be visible, useful for bypassing ASLR /proc/$pid/maps - also useful for bypassing ASLR /proc/$pid/cwd - useful for gaining access to restricted directories that contain files with lax permissions, e.g. in this scenario: lrwxrwxrwx root root /proc/13020/cwd -> /root/foobar drwx------ root root /root drwxr-xr-x root root /root/foobar -rw-r--r-- root root /root/foobar/secret Therefore, on a system where a root-owned mode 6755 binary changes its effective credentials as described and then dumps a user-specified file, this could be used by an attacker to reveal the memory layout of root's processes or reveal the contents of files he is not allowed to access (through /proc/$pid/cwd). [akpm@linux-foundation.org: fix warning] Signed-off-by: Jann Horn Acked-by: Kees Cook Cc: Casey Schaufler Cc: Oleg Nesterov Cc: Ingo Molnar Cc: James Morris Cc: "Serge E. Hallyn" Cc: Andy Shevchenko Cc: Andy Lutomirski Cc: Al Viro Cc: "Eric W. Biederman" Cc: Willy Tarreau Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

security: let security modules use PTRACE_MODE_* with bitmasks

2016-01-21T01:09:18Z

It looks like smack and yama weren't aware that the ptrace mode can have flags ORed into it - PTRACE_MODE_NOAUDIT until now, but only for /proc/$pid/stat, and with the PTRACE_MODE_*CREDS patch, all modes have flags ORed into them. Signed-off-by: Jann Horn Acked-by: Kees Cook Acked-by: Casey Schaufler Cc: Oleg Nesterov Cc: Ingo Molnar Cc: James Morris Cc: "Serge E. Hallyn" Cc: Andy Shevchenko Cc: Andy Lutomirski Cc: Al Viro Cc: "Eric W. Biederman" Cc: Willy Tarreau Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

KEYS: Fix keyring ref leak in join_session_keyring()

2016-01-19T23:50:48Z

This fixes CVE-2016-0728. If a thread is asked to join as a session keyring the keyring that's already set as its session, we leak a keyring reference. This can be tested with the following program: #include #include #include #include int main(int argc, const char *argv[]) { int i = 0; key_serial_t serial; serial = keyctl(KEYCTL_JOIN_SESSION_KEYRING, "leaked-keyring"); if (serial < 0) { perror("keyctl"); return -1; } if (keyctl(KEYCTL_SETPERM, serial, KEY_POS_ALL | KEY_USR_ALL) < 0) { perror("keyctl"); return -1; } for (i = 0; i < 100; i++) { serial = keyctl(KEYCTL_JOIN_SESSION_KEYRING, "leaked-keyring"); if (serial < 0) { perror("keyctl"); return -1; } } return 0; } If, after the program has run, there something like the following line in /proc/keys: 3f3d898f I--Q--- 100 perm 3f3f0000 0 0 keyring leaked-keyring: empty with a usage count of 100 * the number of times the program has been run, then the kernel is malfunctioning. If leaked-keyring has zero usages or has been garbage collected, then the problem is fixed. Reported-by: Yevgeny Pats Signed-off-by: David Howells Acked-by: Don Zickus Acked-by: Prarit Bhargava Acked-by: Jarod Wilson Signed-off-by: James Morris

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

2016-01-18T03:13:15Z

Pull security subsystem updates from James Morris: - EVM gains support for loading an x509 cert from the kernel (EVM_LOAD_X509), into the EVM trusted kernel keyring. - Smack implements 'file receive' process-based permission checking for sockets, rather than just depending on inode checks. - Misc enhancments for TPM & TPM2. - Cleanups and bugfixes for SELinux, Keys, and IMA. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (41 commits) selinux: Inode label revalidation performance fix KEYS: refcount bug fix ima: ima_write_policy() limit locking IMA: policy can be updated zero times selinux: rate-limit netlink message warnings in selinux_nlmsg_perm() selinux: export validatetrans decisions gfs2: Invalid security labels of inodes when they go invalid selinux: Revalidate invalid inode security labels security: Add hook to invalidate inode security labels selinux: Add accessor functions for inode->i_security security: Make inode argument of inode_getsecid non-const security: Make inode argument of inode_getsecurity non-const selinux: Remove unused variable in selinux_inode_init_security keys, trusted: seal with a TPM2 authorization policy keys, trusted: select hash algorithm for TPM2 chips keys, trusted: fix: *do not* allow duplicate key options tpm_ibmvtpm: properly handle interrupted packet receptions tpm_tis: Tighten IRQ auto-probing tpm_tis: Refactor the interrupt setup tpm_tis: Get rid of the duplicate IRQ probing code ...