From 045644540e75a9898a49003e91e24d609f1897b0 Mon Sep 17 00:00:00 2001 From: Lorenz Bauer Date: Thu, 14 Oct 2021 15:25:53 +0100 Subject: bpf: Prevent increasing bpf_jit_limit above max [ Upstream commit fadb7ff1a6c2c565af56b4aacdd086b067eed440 ] Restrict bpf_jit_limit to the maximum supported by the arch's JIT. Signed-off-by: Lorenz Bauer Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20211014142554.53120-4-lmb@cloudflare.com Signed-off-by: Sasha Levin --- kernel/bpf/core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index df2ebce927ec..3ce69c0276c0 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -212,6 +212,7 @@ struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_ALWAYS_ON); int bpf_jit_harden __read_mostly; long bpf_jit_limit __read_mostly; +long bpf_jit_limit_max __read_mostly; static atomic_long_t bpf_jit_current; @@ -231,7 +232,8 @@ 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; } -- cgit v1.2.3