forked from luck/tmp_suning_uos_patched
bpf: perf_event progs should only use preallocated maps
Make sure that BPF_PROG_TYPE_PERF_EVENT programs only use preallocated hash maps, since doing memory allocation in overflow_handler can crash depending on where nmi got triggered. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
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0515e5999a
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fdc15d388d
@ -2511,6 +2511,20 @@ static int do_check(struct verifier_env *env)
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return 0;
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}
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static int check_map_prog_compatibility(struct bpf_map *map,
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struct bpf_prog *prog)
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{
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if (prog->type == BPF_PROG_TYPE_PERF_EVENT &&
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(map->map_type == BPF_MAP_TYPE_HASH ||
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map->map_type == BPF_MAP_TYPE_PERCPU_HASH) &&
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(map->map_flags & BPF_F_NO_PREALLOC)) {
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verbose("perf_event programs can only use preallocated hash map\n");
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return -EINVAL;
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}
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return 0;
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}
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/* look for pseudo eBPF instructions that access map FDs and
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* replace them with actual map pointers
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*/
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@ -2518,7 +2532,7 @@ static int replace_map_fd_with_map_ptr(struct verifier_env *env)
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{
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struct bpf_insn *insn = env->prog->insnsi;
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int insn_cnt = env->prog->len;
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int i, j;
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int i, j, err;
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for (i = 0; i < insn_cnt; i++, insn++) {
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if (BPF_CLASS(insn->code) == BPF_LDX &&
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@ -2562,6 +2576,12 @@ static int replace_map_fd_with_map_ptr(struct verifier_env *env)
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return PTR_ERR(map);
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}
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err = check_map_prog_compatibility(map, env->prog);
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if (err) {
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fdput(f);
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return err;
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}
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/* store map pointer inside BPF_LD_IMM64 instruction */
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insn[0].imm = (u32) (unsigned long) map;
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insn[1].imm = ((u64) (unsigned long) map) >> 32;
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