Re: CVE-2024-50063: bpf: Prevent tail call between progs attached to different hooks

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Thu, Oct 24, 2024 at 12:04:45PM +0800, Shung-Hsi Yu wrote:
> On Mon, Oct 21, 2024 at 09:40:04PM GMT, Greg Kroah-Hartman wrote:
> > Description
> > ===========
> > 
> > In the Linux kernel, the following vulnerability has been resolved:
> > 
> > bpf: Prevent tail call between progs attached to different hooks
> > 
> > bpf progs can be attached to kernel functions, and the attached functions
> > can take different parameters or return different return values. If
> > prog attached to one kernel function tail calls prog attached to another
> > kernel function, the ctx access or return value verification could be
> > bypassed.
> ...
> > This patch adds restriction for tail call to prevent such bypasses.
> > 
> > The Linux kernel CVE team has assigned CVE-2024-50063 to this issue.
> > 
> > 
> > Affected and fixed versions
> > ===========================
> 
> I do not know that exact commit that introduced the issue, but given
> that the fix addresses the following BPF program types:
> - BPF_PROG_TYPE_TRACING (v5.5)
> - BPF_PROG_TYPE_EXT (v5.6)
> - BPF_PROG_TYPE_STRUCT_OPS (v5.6)
> - BPF_PROG_TYPE_LSM (v5.7)
> 
> The earliest affected version possible should be v5.5.

So what commit id should we use?  Can you send a patch adding the
".vulnerable" file to the vulns.git repo for us to mark this properly?

thanks,

greg k-h