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| author | Andrii Nakryiko <andriin@fb.com> | 2020-07-13 16:24:09 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-07-13 17:07:43 -0700 |
| commit | 0b20933d8cfe2bf6473e9b581b5d1ed9a2117ecc (patch) | |
| tree | 79a7e9cabc285400476b921dbdaa4bba220fa46e /tools/bpf | |
| parent | 7c819e701382d4969ca4837b8cbe157895f5d0bf (diff) | |
| download | linux-0b20933d8cfe2bf6473e9b581b5d1ed9a2117ecc.tar.gz linux-0b20933d8cfe2bf6473e9b581b5d1ed9a2117ecc.tar.xz | |
tools/bpftool: Strip away modifiers from global variables
Reliably remove all the type modifiers from read-only (.rodata) global
variable definitions, including cases of inner field const modifiers and
arrays of const values.
Also modify one of selftests to ensure that const volatile struct doesn't
prevent user-space from modifying .rodata variable.
Fixes: 985ead416df3 ("bpftool: Add skeleton codegen command")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200713232409.3062144-3-andriin@fb.com
Diffstat (limited to 'tools/bpf')
| -rw-r--r-- | tools/bpf/bpftool/gen.c | 23 |
1 files changed, 10 insertions, 13 deletions
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c index 10de76b296ba..b59d26e89367 100644 --- a/tools/bpf/bpftool/gen.c +++ b/tools/bpf/bpftool/gen.c @@ -88,7 +88,7 @@ static const char *get_map_ident(const struct bpf_map *map) return NULL; } -static void codegen_btf_dump_printf(void *ct, const char *fmt, va_list args) +static void codegen_btf_dump_printf(void *ctx, const char *fmt, va_list args) { vprintf(fmt, args); } @@ -104,17 +104,20 @@ static int codegen_datasec_def(struct bpf_object *obj, int i, err, off = 0, pad_cnt = 0, vlen = btf_vlen(sec); const char *sec_ident; char var_ident[256]; + bool strip_mods = false; - if (strcmp(sec_name, ".data") == 0) + if (strcmp(sec_name, ".data") == 0) { sec_ident = "data"; - else if (strcmp(sec_name, ".bss") == 0) + } else if (strcmp(sec_name, ".bss") == 0) { sec_ident = "bss"; - else if (strcmp(sec_name, ".rodata") == 0) + } else if (strcmp(sec_name, ".rodata") == 0) { sec_ident = "rodata"; - else if (strcmp(sec_name, ".kconfig") == 0) + strip_mods = true; + } else if (strcmp(sec_name, ".kconfig") == 0) { sec_ident = "kconfig"; - else + } else { return 0; + } printf(" struct %s__%s {\n", obj_name, sec_ident); for (i = 0; i < vlen; i++, sec_var++) { @@ -123,16 +126,10 @@ static int codegen_datasec_def(struct bpf_object *obj, DECLARE_LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts, .field_name = var_ident, .indent_level = 2, + .strip_mods = strip_mods, ); int need_off = sec_var->offset, align_off, align; __u32 var_type_id = var->type; - const struct btf_type *t; - - t = btf__type_by_id(btf, var_type_id); - while (btf_is_mod(t)) { - var_type_id = t->type; - t = btf__type_by_id(btf, var_type_id); - } if (off > need_off) { p_err("Something is wrong for %s's variable #%d: need offset %d, already at %d.\n", |