From: Paul Chaignon <paul.chaignon@orange.com>
To: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
Will Drewry <wad@chromium.org>,
linux-kernel@vger.kernel.org
Subject: [PATCH] seccomp: allow BPF_MOD ALU instructions
Date: Fri, 9 Aug 2019 20:26:22 +0200 [thread overview]
Message-ID: <20190809182621.GA4074@Nover> (raw)
We need BPF_MOD to match system calls against whitelists encoded as 32-bit
bit arrays. The selection of the syscall's bit in the appropriate bit
array requires a modulo operation such that X = 1 << nr % 32.
Signed-off-by: Paul Chaignon <paul.chaignon@orange.com>
---
kernel/seccomp.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 811b4a86cdf6..87de6532ff6d 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -205,6 +205,8 @@ static int seccomp_check_filter(struct sock_filter *filter, unsigned int flen)
case BPF_ALU | BPF_MUL | BPF_X:
case BPF_ALU | BPF_DIV | BPF_K:
case BPF_ALU | BPF_DIV | BPF_X:
+ case BPF_ALU | BPF_MOD | BPF_K:
+ case BPF_ALU | BPF_MOD | BPF_X:
case BPF_ALU | BPF_AND | BPF_K:
case BPF_ALU | BPF_AND | BPF_X:
case BPF_ALU | BPF_OR | BPF_K:
--
2.17.1
next reply other threads:[~2019-08-09 18:26 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-09 18:26 Paul Chaignon [this message]
2019-08-11 8:58 ` [PATCH] seccomp: allow BPF_MOD ALU instructions Paul Chaignon
2019-08-12 17:38 ` Kees Cook
-- strict thread matches above, loose matches on Subject: below --
2020-03-16 16:36 Anton Protopopov
2020-03-16 21:23 ` Kees Cook
2020-03-16 22:17 ` Anton Protopopov
2020-03-17 20:20 ` Kees Cook
2020-03-18 1:11 ` Anton Protopopov
2020-03-18 4:06 ` Kees Cook
2020-03-18 15:23 ` Anton Protopopov
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