From: Eric Biggers Date: Thu, 8 Jun 2017 13:48:40 +0000 (+0100) Subject: KEYS: fix dereferencing NULL payload with nonzero length X-Git-Tag: v3.2.93~32 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=134a3099ea5bb3d13126321ac48bfc48c72784ed;p=pandora-kernel.git 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 Signed-off-by: David Howells Signed-off-by: James Morris [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- Reading git-diff-tree failed