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| author | Eric Biggers <ebiggers@google.com> | 2017-06-08 16:48:40 +0300 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2017-09-15 20:30:52 +0300 |
| commit | 134a3099ea5bb3d13126321ac48bfc48c72784ed (patch) | |
| tree | c4a07c163e6632e7b231e91eb6ce9f82f1ca5138 | |
| parent | 84ffad0113bfd85b5f54be9c141bdd60d77d826a (diff) | |
| download | linux-134a3099ea5bb3d13126321ac48bfc48c72784ed.tar.xz | |
KEYS: fix dereferencing NULL payload with nonzero length
commit 5649645d725c73df4302428ee4e02c869248b4c5 upstream.
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.
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>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | security/keys/keyctl.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c index b9073ebd0817..41525338aa8d 100644 --- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -85,7 +85,7 @@ SYSCALL_DEFINE5(add_key, const char __user *, _type, payload = NULL; vm = false; - if (_payload) { + if (plen) { ret = -ENOMEM; payload = kmalloc(plen, GFP_KERNEL); if (!payload) { @@ -319,7 +319,7 @@ long keyctl_update_key(key_serial_t id, /* pull the payload in if one was supplied */ payload = NULL; - if (_payload) { + if (plen) { ret = -ENOMEM; payload = kmalloc(plen, GFP_KERNEL); if (!payload) |