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| author | Eric Biggers <ebiggers@google.com> | 2017-06-08 14:48:40 +0100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2017-09-15 18:30:07 +0100 |
| commit | 400773b3c6b7faffafc6adedecdd4882fc677d64 (patch) | |
| tree | cb607368601b609676a618f908b4a363ed4e4708 /security/keys | |
| parent | 2ae7cdab3948224b57addd6b82da796aa50d27f7 (diff) | |
| download | linux-stable-400773b3c6b7faffafc6adedecdd4882fc677d64.tar.gz linux-stable-400773b3c6b7faffafc6adedecdd4882fc677d64.tar.bz2 linux-stable-400773b3c6b7faffafc6adedecdd4882fc677d64.zip | |
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 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'security/keys')
| -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 57f8e162b51b..edc3f3c32324 100644 --- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -97,7 +97,7 @@ SYSCALL_DEFINE5(add_key, const char __user *, _type, payload = NULL; vm = false; - if (_payload) { + if (plen) { ret = -ENOMEM; payload = kmalloc(plen, GFP_KERNEL | __GFP_NOWARN); if (!payload) { @@ -331,7 +331,7 @@ 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) |