This is a note to let you know that I've just added the patch titled bpf: Prevent increasing bpf_jit_limit above max to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: bpf-prevent-increasing-bpf_jit_limit-above-max.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 38fd4ec804150a34e62f2081f1524bba08996862 Author: Lorenz Bauer <lmb@xxxxxxxxxxxxxx> Date: Thu Oct 14 15:25:53 2021 +0100 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 <lmb@xxxxxxxxxxxxxx> Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx> Link: https://lore.kernel.org/bpf/20211014142554.53120-4-lmb@xxxxxxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/include/linux/filter.h b/include/linux/filter.h index 5ca676d646529..7c0e616362f05 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -730,6 +730,7 @@ 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 e7211b0fa27cf..485e319ba742a 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -295,6 +295,7 @@ 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, @@ -508,7 +509,8 @@ 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 069e3c4fcc447..ac1a32d5cad3c 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -410,7 +410,7 @@ 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 {