Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Daniel Borkmann says:
====================
pull-request: bpf 2020-07-31
The following pull-request contains BPF updates for your *net* tree.
We've added 5 non-merge commits during the last 21 day(s) which contain
a total of 5 files changed, 126 insertions(+), 18 deletions(-).
The main changes are:
1) Fix a map element leak in HASH_OF_MAPS map type, from Andrii Nakryiko.
2) Fix a NULL pointer dereference in __btf_resolve_helper_id() when no
btf_vmlinux is available, from Peilin Ye.
3) Init pos variable in __bpfilter_process_sockopt(), from Christoph Hellwig.
4) Fix a cgroup sockopt verifier test by specifying expected attach type,
from Jean-Philippe Brucker.
Note that when net gets merged into net-next later on, there is a small
merge conflict in kernel/bpf/btf.c between commit 5b801dfb7feb ("bpf: Fix
NULL pointer dereference in __btf_resolve_helper_id()") from the bpf tree
and commit 138b9a0511c7 ("bpf: Remove btf_id helpers resolving") from the
net-next tree.
Resolve as follows: remove the old hunk with the __btf_resolve_helper_id()
function. Change the btf_resolve_helper_id() so it actually tests for a
NULL btf_vmlinux and bails out:
int btf_resolve_helper_id(struct bpf_verifier_log *log,
const struct bpf_func_proto *fn, int arg)
{
int id;
if (fn->arg_type[arg] != ARG_PTR_TO_BTF_ID || !btf_vmlinux)
return -EINVAL;
id = fn->btf_id[arg];
if (!id || id > btf_vmlinux->nr_types)
return -EINVAL;
return id;
}
Let me know if you run into any others issues (CC'ing Jiri Olsa so he's in
the loop with regards to merge conflict resolution).
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 9a1a98d..0443600 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -4058,6 +4058,11 @@
const char *tname, *sym;
u32 btf_id, i;
+ if (!btf_vmlinux) {
+ bpf_log(log, "btf_vmlinux doesn't exist\n");
+ return -EINVAL;
+ }
+
if (IS_ERR(btf_vmlinux)) {
bpf_log(log, "btf_vmlinux is malformed\n");
return -EINVAL;
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index b4b288a3..b32cc8c 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -779,15 +779,20 @@
htab_elem_free(htab, l);
}
-static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
+static void htab_put_fd_value(struct bpf_htab *htab, struct htab_elem *l)
{
struct bpf_map *map = &htab->map;
+ void *ptr;
if (map->ops->map_fd_put_ptr) {
- void *ptr = fd_htab_map_get_ptr(map, l);
-
+ ptr = fd_htab_map_get_ptr(map, l);
map->ops->map_fd_put_ptr(ptr);
}
+}
+
+static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
+{
+ htab_put_fd_value(htab, l);
if (htab_is_prealloc(htab)) {
__pcpu_freelist_push(&htab->freelist, &l->fnode);
@@ -839,6 +844,7 @@
*/
pl_new = this_cpu_ptr(htab->extra_elems);
l_new = *pl_new;
+ htab_put_fd_value(htab, old_elem);
*pl_new = old_elem;
} else {
struct pcpu_freelist_node *l;
diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c
index 1905e01..4494ea6 100644
--- a/net/bpfilter/bpfilter_kern.c
+++ b/net/bpfilter/bpfilter_kern.c
@@ -39,7 +39,7 @@
{
struct mbox_request req;
struct mbox_reply reply;
- loff_t pos;
+ loff_t pos = 0;
ssize_t n;
int ret = -EFAULT;
diff --git a/tools/testing/selftests/bpf/prog_tests/btf_map_in_map.c b/tools/testing/selftests/bpf/prog_tests/btf_map_in_map.c
index f7ee8fa..6ccecbd 100644
--- a/tools/testing/selftests/bpf/prog_tests/btf_map_in_map.c
+++ b/tools/testing/selftests/bpf/prog_tests/btf_map_in_map.c
@@ -5,10 +5,60 @@
#include "test_btf_map_in_map.skel.h"
+static int duration;
+
+static __u32 bpf_map_id(struct bpf_map *map)
+{
+ struct bpf_map_info info;
+ __u32 info_len = sizeof(info);
+ int err;
+
+ memset(&info, 0, info_len);
+ err = bpf_obj_get_info_by_fd(bpf_map__fd(map), &info, &info_len);
+ if (err)
+ return 0;
+ return info.id;
+}
+
+/*
+ * Trigger synchronize_rcu() in kernel.
+ *
+ * ARRAY_OF_MAPS/HASH_OF_MAPS lookup/update operations trigger synchronize_rcu()
+ * if looking up an existing non-NULL element or updating the map with a valid
+ * inner map FD. Use this fact to trigger synchronize_rcu(): create map-in-map,
+ * create a trivial ARRAY map, update map-in-map with ARRAY inner map. Then
+ * cleanup. At the end, at least one synchronize_rcu() would be called.
+ */
+static int kern_sync_rcu(void)
+{
+ int inner_map_fd, outer_map_fd, err, zero = 0;
+
+ inner_map_fd = bpf_create_map(BPF_MAP_TYPE_ARRAY, 4, 4, 1, 0);
+ if (CHECK(inner_map_fd < 0, "inner_map_create", "failed %d\n", -errno))
+ return -1;
+
+ outer_map_fd = bpf_create_map_in_map(BPF_MAP_TYPE_ARRAY_OF_MAPS, NULL,
+ sizeof(int), inner_map_fd, 1, 0);
+ if (CHECK(outer_map_fd < 0, "outer_map_create", "failed %d\n", -errno)) {
+ close(inner_map_fd);
+ return -1;
+ }
+
+ err = bpf_map_update_elem(outer_map_fd, &zero, &inner_map_fd, 0);
+ if (err)
+ err = -errno;
+ CHECK(err, "outer_map_update", "failed %d\n", err);
+ close(inner_map_fd);
+ close(outer_map_fd);
+ return err;
+}
+
void test_btf_map_in_map(void)
{
- int duration = 0, err, key = 0, val;
- struct test_btf_map_in_map* skel;
+ int err, key = 0, val, i;
+ struct test_btf_map_in_map *skel;
+ int outer_arr_fd, outer_hash_fd;
+ int fd, map1_fd, map2_fd, map1_id, map2_id;
skel = test_btf_map_in_map__open_and_load();
if (CHECK(!skel, "skel_open", "failed to open&load skeleton\n"))
@@ -18,32 +68,78 @@
if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
goto cleanup;
+ map1_fd = bpf_map__fd(skel->maps.inner_map1);
+ map2_fd = bpf_map__fd(skel->maps.inner_map2);
+ outer_arr_fd = bpf_map__fd(skel->maps.outer_arr);
+ outer_hash_fd = bpf_map__fd(skel->maps.outer_hash);
+
/* inner1 = input, inner2 = input + 1 */
- val = bpf_map__fd(skel->maps.inner_map1);
- bpf_map_update_elem(bpf_map__fd(skel->maps.outer_arr), &key, &val, 0);
- val = bpf_map__fd(skel->maps.inner_map2);
- bpf_map_update_elem(bpf_map__fd(skel->maps.outer_hash), &key, &val, 0);
+ map1_fd = bpf_map__fd(skel->maps.inner_map1);
+ bpf_map_update_elem(outer_arr_fd, &key, &map1_fd, 0);
+ map2_fd = bpf_map__fd(skel->maps.inner_map2);
+ bpf_map_update_elem(outer_hash_fd, &key, &map2_fd, 0);
skel->bss->input = 1;
usleep(1);
- bpf_map_lookup_elem(bpf_map__fd(skel->maps.inner_map1), &key, &val);
+ bpf_map_lookup_elem(map1_fd, &key, &val);
CHECK(val != 1, "inner1", "got %d != exp %d\n", val, 1);
- bpf_map_lookup_elem(bpf_map__fd(skel->maps.inner_map2), &key, &val);
+ bpf_map_lookup_elem(map2_fd, &key, &val);
CHECK(val != 2, "inner2", "got %d != exp %d\n", val, 2);
/* inner1 = input + 1, inner2 = input */
- val = bpf_map__fd(skel->maps.inner_map2);
- bpf_map_update_elem(bpf_map__fd(skel->maps.outer_arr), &key, &val, 0);
- val = bpf_map__fd(skel->maps.inner_map1);
- bpf_map_update_elem(bpf_map__fd(skel->maps.outer_hash), &key, &val, 0);
+ bpf_map_update_elem(outer_arr_fd, &key, &map2_fd, 0);
+ bpf_map_update_elem(outer_hash_fd, &key, &map1_fd, 0);
skel->bss->input = 3;
usleep(1);
- bpf_map_lookup_elem(bpf_map__fd(skel->maps.inner_map1), &key, &val);
+ bpf_map_lookup_elem(map1_fd, &key, &val);
CHECK(val != 4, "inner1", "got %d != exp %d\n", val, 4);
- bpf_map_lookup_elem(bpf_map__fd(skel->maps.inner_map2), &key, &val);
+ bpf_map_lookup_elem(map2_fd, &key, &val);
CHECK(val != 3, "inner2", "got %d != exp %d\n", val, 3);
+ for (i = 0; i < 5; i++) {
+ val = i % 2 ? map1_fd : map2_fd;
+ err = bpf_map_update_elem(outer_hash_fd, &key, &val, 0);
+ if (CHECK_FAIL(err)) {
+ printf("failed to update hash_of_maps on iter #%d\n", i);
+ goto cleanup;
+ }
+ err = bpf_map_update_elem(outer_arr_fd, &key, &val, 0);
+ if (CHECK_FAIL(err)) {
+ printf("failed to update hash_of_maps on iter #%d\n", i);
+ goto cleanup;
+ }
+ }
+
+ map1_id = bpf_map_id(skel->maps.inner_map1);
+ map2_id = bpf_map_id(skel->maps.inner_map2);
+ CHECK(map1_id == 0, "map1_id", "failed to get ID 1\n");
+ CHECK(map2_id == 0, "map2_id", "failed to get ID 2\n");
+
+ test_btf_map_in_map__destroy(skel);
+ skel = NULL;
+
+ /* we need to either wait for or force synchronize_rcu(), before
+ * checking for "still exists" condition, otherwise map could still be
+ * resolvable by ID, causing false positives.
+ *
+ * Older kernels (5.8 and earlier) freed map only after two
+ * synchronize_rcu()s, so trigger two, to be entirely sure.
+ */
+ CHECK(kern_sync_rcu(), "sync_rcu", "failed\n");
+ CHECK(kern_sync_rcu(), "sync_rcu", "failed\n");
+
+ fd = bpf_map_get_fd_by_id(map1_id);
+ if (CHECK(fd >= 0, "map1_leak", "inner_map1 leaked!\n")) {
+ close(fd);
+ goto cleanup;
+ }
+ fd = bpf_map_get_fd_by_id(map2_id);
+ if (CHECK(fd >= 0, "map2_leak", "inner_map2 leaked!\n")) {
+ close(fd);
+ goto cleanup;
+ }
+
cleanup:
test_btf_map_in_map__destroy(skel);
}
diff --git a/tools/testing/selftests/bpf/verifier/event_output.c b/tools/testing/selftests/bpf/verifier/event_output.c
index 99f8f58..c5e8059 100644
--- a/tools/testing/selftests/bpf/verifier/event_output.c
+++ b/tools/testing/selftests/bpf/verifier/event_output.c
@@ -112,6 +112,7 @@
"perfevent for cgroup sockopt",
.insns = { __PERF_EVENT_INSNS__ },
.prog_type = BPF_PROG_TYPE_CGROUP_SOCKOPT,
+ .expected_attach_type = BPF_CGROUP_SETSOCKOPT,
.fixup_map_event_output = { 4 },
.result = ACCEPT,
.retval = 1,
