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authorEric Biggers <ebiggers@google.com>2017-06-08 14:48:40 +0100
committerJames Morris <james.l.morris@oracle.com>2017-06-09 13:29:47 +1000
commit5649645d725c73df4302428ee4e02c869248b4c5 (patch)
tree14116cd39ec4d20e8656e22a108d3691a46e37d3 /security/keys/keyctl.c
parentKEYS: encrypted: use constant-time HMAC comparison (diff)
downloadlinux-dev-5649645d725c73df4302428ee4e02c869248b4c5.tar.xz
linux-dev-5649645d725c73df4302428ee4e02c869248b4c5.zip
KEYS: fix dereferencing NULL payload with nonzero length
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. Cc: stable@vger.kernel.org # 2.6.10+ 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>
Diffstat (limited to '')
-rw-r--r--security/keys/keyctl.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index 447a7d5cee0f..94c2790f8283 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -99,7 +99,7 @@ SYSCALL_DEFINE5(add_key, const char __user *, _type,
/* pull the payload in if one was supplied */
payload = NULL;
- if (_payload) {
+ if (plen) {
ret = -ENOMEM;
payload = kvmalloc(plen, GFP_KERNEL);
if (!payload)
@@ -324,7 +324,7 @@ 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)