Messages in this thread | | | From | Jann Horn <> | Date | Mon, 3 Sep 2018 17:55:23 +0200 | Subject | Re: [PATCH] firewire: nosy: don't read packets bigger than requested |
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On Fri, Jul 6, 2018 at 5:16 PM Jann Horn <jannh@google.com> wrote: > In general, accessing userspace memory beyond the length of the supplied > buffer in VFS read/write handlers can lead to both kernel memory corruption > (via kernel_read()/kernel_write(), which can e.g. be triggered via > sys_splice()) and privilege escalation inside userspace. > > Fixes: 286468210d83 ("firewire: new driver: nosy - IEEE 1394 traffic sniffer") > Signed-off-by: Jann Horn <jannh@google.com> > --- > No CC stable because this device shouldn't be available to unprivileged > code by default and should be pretty rare. > > drivers/firewire/nosy.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/firewire/nosy.c b/drivers/firewire/nosy.c > index a128dd1126ae..732075fc312e 100644 > --- a/drivers/firewire/nosy.c > +++ b/drivers/firewire/nosy.c > @@ -161,11 +161,12 @@ packet_buffer_get(struct client *client, char __user *data, size_t user_length) > if (atomic_read(&buffer->size) == 0) > return -ENODEV; > > - /* FIXME: Check length <= user_length. */ > - > end = buffer->data + buffer->capacity; > length = buffer->head->length; > > + if (length > user_length) > + return -EINVAL; > + > if (&buffer->head->data[length] < end) { > if (copy_to_user(data, buffer->head->data, length)) > return -EFAULT;
Ping. I sent this about two months ago, I haven't received a reply, and from what I can tell, it hasn't landed in any tree so far...
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