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Commit 5c6fb0e0 authored by Lorenz Bauer's avatar Lorenz Bauer Committed by Greg Kroah-Hartman
Browse files

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: default avatarLorenz Bauer <lmb@cloudflare.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211014142554.53120-4-lmb@cloudflare.com


Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 0e7e6e04

include/linux/filter.h

+1 −0
Original line number Diff line number Diff line
@@ -877,6 +877,7 @@ 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);

kernel/bpf/core.c

+3 −1
Original line number Diff line number Diff line
@@ -372,6 +372,7 @@ int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_ALWAYS_ON); 
int bpf_jit_harden   __read_mostly;

int bpf_jit_kallsyms __read_mostly;

long bpf_jit_limit   __read_mostly;

long bpf_jit_limit_max __read_mostly;



static __always_inline void

bpf_get_prog_addr_region(const struct bpf_prog *prog,
@@ -598,7 +599,8 @@ 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;

}

net/core/sysctl_net_core.c

+1 −1
Original line number Diff line number Diff line
@@ -417,7 +417,7 @@ 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

	{