4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> commit 1f5781725dcbb026438e77091c91a94f678c3522 upstream. syzbot is reporting NULL pointer dereference at xattr_getsecurity() [1], for cap_inode_getsecurity() is returning sizeof(struct vfs_cap_data) when memory allocation failed. Return -ENOMEM if memory allocation failed. [1] https://syzkaller.appspot.com/bug?id=a55ba438506fe68649a5f50d2d82d56b365e0107 Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Fixes: 8db6c34f1dbc8e06 ("Introduce v3 namespaced file capabilities") Reported-by: syzbot <syzbot+9369930ca44f29e60e2d@xxxxxxxxxxxxxxxxxxxxxxxxx> Cc: stable <stable@xxxxxxxxxxxxxxx> # 4.14+ Acked-by: Serge E. Hallyn <serge@xxxxxxxxxx> Acked-by: James Morris <james.morris@xxxxxxxxxxxxx> Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- security/commoncap.c | 2 ++ 1 file changed, 2 insertions(+) --- a/security/commoncap.c +++ b/security/commoncap.c @@ -449,6 +449,8 @@ int cap_inode_getsecurity(struct inode * magic |= VFS_CAP_FLAGS_EFFECTIVE; memcpy(&cap->data, &nscap->data, sizeof(__le32) * 2 * VFS_CAP_U32); cap->magic_etc = cpu_to_le32(magic); + } else { + size = -ENOMEM; } } kfree(tmpbuf);