979e0d7465
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 <tt.rantala@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|---|---|---|
| .. | ||
| apparmor | ||
| integrity | ||
| keys | ||
| selinux | ||
| smack | ||
| tomoyo | ||
| yama | ||
| capability.c | ||
| commoncap.c | ||
| device_cgroup.c | ||
| inode.c | ||
| Kconfig | ||
| lsm_audit.c | ||
| Makefile | ||
| min_addr.c | ||
| security.c | ||