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

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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: fcfb126def ("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
This commit is contained in:
Johannes Krude 2020-02-12 20:32:27 +01:00 committed by Daniel Borkmann
parent eecd618b45
commit e20d3a055a
1 changed files with 1 additions and 1 deletions
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kernel/bpf/offload.c
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@ -321,7 +321,7 @@ 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)) {