diff options
| -rw-r--r-- | samples/bpf/bpf_load.c | 40 |
1 files changed, 31 insertions, 9 deletions
diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c index d4433a47e6c3..0ec0dea3c41e 100644 --- a/samples/bpf/bpf_load.c +++ b/samples/bpf/bpf_load.c @@ -185,12 +185,16 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size) return 0; } -static int load_maps(struct bpf_map_def *maps, int len, +static int load_maps(struct bpf_map_def *maps, int nr_maps, const char **map_names, fixup_map_cb fixup_map) { int i; - - for (i = 0; i < len / sizeof(struct bpf_map_def); i++) { + /* + * Warning: Using "maps" pointing to ELF data_maps->d_buf as + * an array of struct bpf_map_def is a wrong assumption about + * the ELF maps section format. + */ + for (i = 0; i < nr_maps; i++) { if (fixup_map) fixup_map(&maps[i], map_names[i], i); @@ -269,6 +273,10 @@ static int parse_relo_and_apply(Elf_Data *data, Elf_Data *symbols, return 1; } insn[insn_idx].src_reg = BPF_PSEUDO_MAP_FD; + /* + * Warning: Using sizeof(struct bpf_map_def) here is a + * wrong assumption about ELF maps section format + */ insn[insn_idx].imm = map_fd[sym.st_value / sizeof(struct bpf_map_def)]; } @@ -311,18 +319,18 @@ static int get_sorted_map_names(Elf *elf, Elf_Data *symbols, int maps_shndx, map_name = elf_strptr(elf, strtabidx, map_symbols[i].st_name); if (!map_name) { printf("cannot get map symbol\n"); - return 1; + return -1; } map_names[i] = strdup(map_name); if (!map_names[i]) { printf("strdup(%s): %s(%d)\n", map_name, strerror(errno), errno); - return 1; + return -1; } } - return 0; + return nr_maps; } static int do_load_bpf_file(const char *path, fixup_map_cb fixup_map) @@ -396,11 +404,25 @@ static int do_load_bpf_file(const char *path, fixup_map_cb fixup_map) } if (data_maps) { - if (get_sorted_map_names(elf, symbols, maps_shndx, strtabidx, - map_names)) + int nr_maps; + int prog_elf_map_sz; + + nr_maps = get_sorted_map_names(elf, symbols, maps_shndx, + strtabidx, map_names); + if (nr_maps < 0) goto done; - if (load_maps(data_maps->d_buf, data_maps->d_size, + /* Deduce map struct size stored in ELF maps section */ + prog_elf_map_sz = data_maps->d_size / nr_maps; + if (prog_elf_map_sz != sizeof(struct bpf_map_def)) { + printf("Error: ELF maps sec wrong size (%d/%lu)," + " old kern.o file?\n", + prog_elf_map_sz, sizeof(struct bpf_map_def)); + ret = 1; + goto done; + } + + if (load_maps(data_maps->d_buf, nr_maps, (const char **)map_names, fixup_map)) goto done; |