diff options
| author | Eric Biggers <ebiggers@google.com> | 2017-06-08 14:49:26 +0100 |
|---|---|---|
| committer | James Morris <james.l.morris@oracle.com> | 2017-06-09 13:29:48 +1000 |
| commit | 0620fddb56dfaf0e1034eeb69d79c73b361debbf (patch) | |
| tree | e946b82852f2e72c559a1acaa458e7d6e0173acc | |
| parent | ee618b4619b72527aaed765f0f0b74072b281159 (diff) | |
KEYS: sanitize key structs before freeing
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>
| -rw-r--r-- | include/linux/key.h | 1 | ||||
| -rw-r--r-- | security/keys/gc.c | 4 |
2 files changed, 1 insertions, 4 deletions
diff --git a/include/linux/key.h b/include/linux/key.h index 0c9b93b0d1f7..78e25aabedaf 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -173,7 +173,6 @@ struct key { #ifdef KEY_DEBUGGING unsigned magic; #define KEY_DEBUG_MAGIC 0x18273645u -#define KEY_DEBUG_MAGIC_X 0xf8e9dacbu #endif unsigned long flags; /* status flags (change with bitops) */ diff --git a/security/keys/gc.c b/security/keys/gc.c index 595becc6d0d2..87cb260e4890 100644 --- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -158,9 +158,7 @@ static noinline void key_gc_unused_keys(struct list_head *keys) kfree(key->description); -#ifdef KEY_DEBUGGING - key->magic = KEY_DEBUG_MAGIC_X; -#endif + memzero_explicit(key, sizeof(*key)); kmem_cache_free(key_jar, key); } } |