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bpf: check for owner_prog_type and notify users when differ 

Kernel commit 21116b7068b9 ("bpf: add owner_prog_type and accounted mem
to array map's fdinfo") added support for telling the owner prog type in
case of prog arrays. Give a notification to the user when they differ,
and the program eventually fails to load.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Daniel Borkmann 2016-12-06 02:17:58 +01:00 committed by Stephen Hemminger
parent 0f74d0f3a9
commit fb24802b9c
1 changed files with 14 additions and 4 deletions
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18
lib/bpf.c
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@ -273,11 +273,11 @@ static void bpf_map_pin_report(const struct bpf_elf_map *pin,
} }
static int bpf_map_selfcheck_pinned(int fd, const struct bpf_elf_map *map, static int bpf_map_selfcheck_pinned(int fd, const struct bpf_elf_map *map,
int length) int length, enum bpf_prog_type type)
{ {
char file[PATH_MAX], buff[4096]; char file[PATH_MAX], buff[4096];
struct bpf_elf_map tmp = {}, zero = {}; struct bpf_elf_map tmp = {}, zero = {};
unsigned int val; unsigned int val, owner_type = 0;
FILE *fp; FILE *fp;
snprintf(file, sizeof(file), "/proc/%d/fdinfo/%d", getpid(), fd); snprintf(file, sizeof(file), "/proc/%d/fdinfo/%d", getpid(), fd);
@ -299,10 +299,19 @@ static int bpf_map_selfcheck_pinned(int fd, const struct bpf_elf_map *map,
tmp.max_elem = val; tmp.max_elem = val;
else if (sscanf(buff, "map_flags:\t%i", &val) == 1) else if (sscanf(buff, "map_flags:\t%i", &val) == 1)
tmp.flags = val; tmp.flags = val;
else if (sscanf(buff, "owner_prog_type:\t%i", &val) == 1)
owner_type = val;
} }
fclose(fp); fclose(fp);
/* The decision to reject this is on kernel side eventually, but
* at least give the user a chance to know what's wrong.
*/
if (owner_type && owner_type != type)
fprintf(stderr, "Program array map owner types differ: %u (obj) != %u (pin)\n",
type, owner_type);
if (!memcmp(&tmp, map, length)) { if (!memcmp(&tmp, map, length)) {
return 0; return 0;
} else { } else {
@ -818,7 +827,8 @@ int bpf_graft_map(const char *map_path, uint32_t *key, int argc, char **argv)
} }
ret = bpf_map_selfcheck_pinned(map_fd, &test, ret = bpf_map_selfcheck_pinned(map_fd, &test,
offsetof(struct bpf_elf_map, max_elem)); offsetof(struct bpf_elf_map, max_elem),
type);
if (ret < 0) { if (ret < 0) {
fprintf(stderr, "Map \'%s\' self-check failed!\n", map_path); fprintf(stderr, "Map \'%s\' self-check failed!\n", map_path);
goto out_map; goto out_map;
@ -1303,7 +1313,7 @@ static int bpf_map_attach(const char *name, const struct bpf_elf_map *map,
if (fd > 0) { if (fd > 0) {
ret = bpf_map_selfcheck_pinned(fd, map, ret = bpf_map_selfcheck_pinned(fd, map,
offsetof(struct bpf_elf_map, offsetof(struct bpf_elf_map,
id)); id), ctx->type);
if (ret < 0) { if (ret < 0) {
close(fd); close(fd);
fprintf(stderr, "Map \'%s\' self-check failed!\n", fprintf(stderr, "Map \'%s\' self-check failed!\n",