[PATCH] seccomp: allow BPF_MOD ALU instructions

From: Anton Protopopov
Date: Mon Mar 16 2020 - 12:37:31 EST


The BPF_MOD ALU instructions could be utilized by seccomp classic BPF filters,
but were missing from the explicit list of allowed calls since its introduction
in the original e2cfabdfd075 ("seccomp: add system call filtering using BPF")
commit. Add support for these instructions by adding them to the allowed list
in the seccomp_check_filter function.

Signed-off-by: Anton Protopopov <a.s.protopopov@xxxxxxxxx>
---
kernel/seccomp.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index b6ea3dcb57bf..cae7561b44d4 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -206,6 +206,8 @@ 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:
--
2.19.1