Messages in this thread | | | Date | Tue, 2 Jan 2024 14:47:51 +0100 | From | Jan Kara <> | Subject | Re: [PATCH] fanotify: avoid possible NULL dereference |
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On Thu 10-08-23 20:58:16, Amir Goldstein wrote: > On Tue, Aug 8, 2023 at 12:19 PM Su Hui <suhui@nfschina.com> wrote: > > > > smatch error: > > fs/notify/fanotify/fanotify_user.c:462 copy_fid_info_to_user(): > > we previously assumed 'fh' could be null (see line 421) > > > > Fixes: afc894c784c8 ("fanotify: Store fanotify handles differently") > > Signed-off-by: Su Hui <suhui@nfschina.com>' > > Reviewed-by: Amir Goldstein <amir73il@gmail.com>
I'm sorry but this has somehow fallen through the cracks.
> > diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c > > index f69c451018e3..5a5487ae2460 100644 > > --- a/fs/notify/fanotify/fanotify_user.c > > +++ b/fs/notify/fanotify/fanotify_user.c > > @@ -459,12 +459,13 @@ static int copy_fid_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh, > > if (WARN_ON_ONCE(len < sizeof(handle))) > > return -EFAULT; > > > > - handle.handle_type = fh->type; > > handle.handle_bytes = fh_len;
Well, if passed 'fh' is NULL, we have problems later in the function anyway. E.g. in fanotify_fh_buf() a few lines below. So I think this needs a bit more work that just this small fixup...
Honza
> > > > /* Mangle handle_type for bad file_handle */ > > if (!fh_len) > > handle.handle_type = FILEID_INVALID; > > + else > > + handle.handle_type = fh->type; > > > > if (copy_to_user(buf, &handle, sizeof(handle))) > > return -EFAULT; > > -- > > 2.30.2 > > -- Jan Kara <jack@suse.com> SUSE Labs, CR
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