Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> writes: > From 904d07a6eb014f3df0c5a1ebfcfd4323276a9a76 Mon Sep 17 00:00:00 2001 > From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> > Date: Tue, 10 Apr 2018 15:15:16 +0900 > Subject: [PATCH] commoncap: Handle memory allocation failure. > > 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 Acked-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> Tetsuo I can pick this up, or do you have preferred path for getting this change merged? Serge does this fix look ok to you? I am a bit worried that might be a bit brittler but I don't see any issues with this change. Eric > 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+ > Cc: Serge E. Hallyn <serge@xxxxxxxxxx> > Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx> > --- > security/commoncap.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/security/commoncap.c b/security/commoncap.c > index 48620c9..1ce701f 100644 > --- a/security/commoncap.c > +++ b/security/commoncap.c > @@ -449,6 +449,8 @@ int cap_inode_getsecurity(struct inode *inode, const char *name, void **buffer, > 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); > -- > 1.8.3.1
