From: Johannes Krude <johannes@krude.de>
To: bpf@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <jakub.kicinski@netronome.com>,
trivial@kernel.org
Subject: [PATCH] bpf_prog_offload_info_fill: replace bitwise AND by logical AND
Date: Wed, 12 Feb 2020 20:32:27 +0100 [thread overview]
Message-ID: <20200212193227.GA3769@phlox.h.transitiv.net> (raw)
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.
Signed-off-by: Johannes Krude <johannes@krude.de>
---
kernel/bpf/offload.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c
index 2c5dc6541..bd09290e3 100644
--- a/kernel/bpf/offload.c
+++ b/kernel/bpf/offload.c
@@ -321,7 +321,7 @@ int bpf_prog_offload_info_fill(struct bpf_prog_info *info,
ulen = info->jited_prog_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);
ulen = min_t(u32, info->jited_prog_len, ulen);
if (copy_to_user(uinsns, aux->offload->jited_image, ulen)) {
--
2.24.0
next reply other threads:[~2020-02-12 19:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-12 19:32 Johannes Krude [this message]
2020-02-13 3:38 ` [PATCH] bpf_prog_offload_info_fill: replace bitwise AND by logical AND Jakub Kicinski
2020-02-17 15:56 ` Daniel Borkmann
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