bpf: reject out-of-bounds stack pointer calculation

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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: 7bca0a9702 ("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>

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Daniel Borkmann 2017-12-22 16:29:04 +01:00 • committed by Greg Kroah-Hartman

parent 7b5b73ea87

commit d75d3ee237

1 changed files with 20 additions and 2 deletions

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kernel/bpf/verifier.c

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