Commit bf3043d2 authored Feb 12, 2020 by Johannes Krude Committed by Greg Kroah-Hartman Feb 28, 2020

bpf, offload: Replace bitwise AND by logical AND in bpf_prog_offload_info_fill

commit e20d3a055a457a10a4c748ce5b7c2ed3173a1324 upstream.

This if guards whether user-space wants a copy of the offload-jited
bytecode and whether this bytecode exists. By erroneously doing a bitwise
AND instead of a logical AND on user- and kernel-space buffer-size can lead
to no data being copied to user-space especially when user-space size is a
power of two and bigger then the kernel-space buffer.

Fixes: fcfb126d ("bpf: add new jited info fields in bpf_dev_offload and bpf_prog_info")
Signed-off-by: Johannes Krude <johannes@krude.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/bpf/20200212193227.GA3769@phlox.h.transitiv.net

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 3132696d

kernel/bpf/offload.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -289,7 +289,7 @@ int bpf_prog_offload_info_fill(struct bpf_prog_info *info,

	ulen = info->jited_prog_len;		ulen = info->jited_prog_len;
	info->jited_prog_len = aux->offload->jited_len;		info->jited_prog_len = aux->offload->jited_len;
	if (info->jited_prog_len & ulen) {		if (info->jited_prog_len && ulen) {
	uinsns = u64_to_user_ptr(info->jited_prog_insns);		uinsns = u64_to_user_ptr(info->jited_prog_insns);
	ulen = min_t(u32, info->jited_prog_len, ulen);		ulen = min_t(u32, info->jited_prog_len, ulen);
	if (copy_to_user(uinsns, aux->offload->jited_image, ulen)) {		if (copy_to_user(uinsns, aux->offload->jited_image, ulen)) {