Re: [PATCH] bpf: explicitly memset the bpf_attr structure

From: Daniel Borkmann
Date: Fri Mar 20 2020 - 16:07:32 EST


On 3/20/20 10:48 AM, Greg Kroah-Hartman wrote:
For the bpf syscall, we are relying on the compiler to properly zero out
the bpf_attr union that we copy userspace data into. Unfortunately that
doesn't always work properly, padding and other oddities might not be
correctly zeroed, and in some tests odd things have been found when the
stack is pre-initialized to other values.

Fix this by explicitly memsetting the structure to 0 before using it.

Reported-by: Maciej Åenczykowski <maze@xxxxxxxxxx>
Reported-by: John Stultz <john.stultz@xxxxxxxxxx>
Reported-by: Alexander Potapenko <glider@xxxxxxxxxx>
Reported-by: Alistair Delva <adelva@xxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Link: https://android-review.googlesource.com/c/kernel/common/+/1235490
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

Applied, thanks!