tree 787369e2a9360b16329b5fcee3007ab063003155
parent 7b5b73ea87a06236fa124bdebed1390d362d3439
author Daniel Borkmann <daniel@iogearbox.net> 1513956544 +0100
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1514208227 +0100

bpf: reject out-of-bounds stack pointer calculation


From: Jann Horn <jannh@google.com>

Reject programs that compute wildly out-of-bounds stack pointers.
Otherwise, pointers can be computed with an offset that doesn't fit into an
`int`, causing security issues in the stack memory access check (as well as
signed integer overflow during offset addition).

This is a fix specifically for the v4.9 stable tree because the mainline
code looks very different at this point.

Fixes: 7bca0a9702edf ("bpf: enhance verifier to understand stack pointer arithmetic")
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>