From: Lorenz Bauer <lmb@cloudflare.com>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>
Cc: kernel-team@cloudflare.com, Lorenz Bauer <lmb@cloudflare.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH bpf-next 3/4] bpf: prevent increasing bpf_jit_limit above max
Date: Fri, 24 Sep 2021 10:55:41 +0100 [thread overview]
Message-ID: <20210924095542.33697-4-lmb@cloudflare.com> (raw)
In-Reply-To: <20210924095542.33697-1-lmb@cloudflare.com>
Restrict bpf_jit_limit to the maximum supported by the arch's JIT.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
---
include/linux/filter.h | 1 +
kernel/bpf/core.c | 4 +++-
net/core/sysctl_net_core.c | 2 +-
3 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 4a93c12543ee..ef03ff34234d 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -1051,6 +1051,7 @@ extern int bpf_jit_enable;
extern int bpf_jit_harden;
extern int bpf_jit_kallsyms;
extern long bpf_jit_limit;
+extern long bpf_jit_limit_max;
typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 6fddc13fe67f..e844a2a4c99a 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -524,6 +524,7 @@ int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
int bpf_jit_harden __read_mostly;
long bpf_jit_limit __read_mostly;
+long bpf_jit_limit_max __read_mostly;
static void
bpf_prog_ksym_set_addr(struct bpf_prog *prog)
@@ -817,7 +818,8 @@ u64 __weak bpf_jit_alloc_exec_limit(void)
static int __init bpf_jit_charge_init(void)
{
/* Only used as heuristic here to derive limit. */
- bpf_jit_limit = min_t(u64, round_up(bpf_jit_alloc_exec_limit() >> 2,
+ bpf_jit_limit_max = bpf_jit_alloc_exec_limit();
+ bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 2,
PAGE_SIZE), LONG_MAX);
return 0;
}
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index c8496c1142c9..5f88526ad61c 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -419,7 +419,7 @@ static struct ctl_table net_core_table[] = {
.mode = 0600,
.proc_handler = proc_dolongvec_minmax_bpf_restricted,
.extra1 = &long_one,
- .extra2 = &long_max,
+ .extra2 = &bpf_jit_limit_max,
},
#endif
{
--
2.30.2
next prev parent reply other threads:[~2021-09-24 9:56 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-24 9:55 [PATCH bpf-next 0/4] Fix up bpf_jit_limit some more Lorenz Bauer
2021-09-24 9:55 ` [PATCH bpf-next 1/4] bpf: define bpf_jit_alloc_exec_limit for riscv JIT Lorenz Bauer
2021-09-24 15:28 ` Luke Nelson
2021-09-24 9:55 ` [PATCH bpf-next 2/4] bpf: define bpf_jit_alloc_exec_limit for arm64 JIT Lorenz Bauer
2021-09-29 16:18 ` Will Deacon
2021-09-24 9:55 ` Lorenz Bauer [this message]
2021-09-24 9:55 ` [PATCH bpf-next 4/4] bpf: export bpf_jit_current Lorenz Bauer
2021-09-27 13:34 ` Daniel Borkmann
2021-09-27 14:01 ` Jakub Sitnicki
2021-09-28 9:02 ` Lorenz Bauer
2021-09-29 14:56 ` Nicolas Dichtel
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