kernel.git/tools/testing/selftests/bpf, branch linux-4.14.y

bpf: Fix the off-by-two error in range markings

2022-09-15T10:23:49Z

commit 2fa7d94afc1afbb4d702760c058dc2d7ed30f226 upstream. The first commit cited below attempts to fix the off-by-one error that appeared in some comparisons with an open range. Due to this error, arithmetically equivalent pieces of code could get different verdicts from the verifier, for example (pseudocode): // 1. Passes the verifier: if (data + 8 > data_end) return early read *(u64 *)data, i.e. [data; data+7] // 2. Rejected by the verifier (should still pass): if (data + 7 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The attempted fix, however, shifts the range by one in a wrong direction, so the bug not only remains, but also such piece of code starts failing in the verifier: // 3. Rejected by the verifier, but the check is stricter than in #1. if (data + 8 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The change performed by that fix converted an off-by-one bug into off-by-two. The second commit cited below added the BPF selftests written to ensure than code chunks like #3 are rejected, however, they should be accepted. This commit fixes the off-by-two error by adjusting new_range in the right direction and fixes the tests by changing the range into the one that should actually fail. Fixes: fb2a311a31d3 ("bpf: fix off by one for range markings with L{T, E} patterns") Fixes: b37242c773b2 ("bpf: add test cases to bpf selftests to cover all access tests") Signed-off-by: Maxim Mikityanskiy Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20211130181607.593149-1-maximmi@nvidia.com [OP: only cherry-pick selftest changes applicable to 4.14] Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman

selftests/bpf: Fix test_align verifier log patterns

2022-09-15T10:23:49Z

commit 5366d2269139ba8eb6a906d73a0819947e3e4e0a upstream. Commit 294f2fc6da27 ("bpf: Verifer, adjust_scalar_min_max_vals to always call update_reg_bounds()") changed the way verifier logs some of its state, adjust the test_align accordingly. Where possible, I tried to not copy-paste the entire log line and resorted to dropping the last closing brace instead. Fixes: 294f2fc6da27 ("bpf: Verifer, adjust_scalar_min_max_vals to always call update_reg_bounds()") Signed-off-by: Stanislav Fomichev Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20200515194904.229296-1-sdf@google.com [OP: adjust for 4.14 selftests, apply only the relevant diffs] Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman

bpf: fix panic due to oob in bpf_prog_test_run_skb

2021-12-22T08:17:58Z

commit 6e6fddc78323533be570873abb728b7e0ba7e024 upstream. sykzaller triggered several panics similar to the below: [...] [ 248.851531] BUG: KASAN: use-after-free in _copy_to_user+0x5c/0x90 [ 248.857656] Read of size 985 at addr ffff8808017ffff2 by task a.out/1425 [...] [ 248.865902] CPU: 1 PID: 1425 Comm: a.out Not tainted 4.18.0-rc4+ #13 [ 248.865903] Hardware name: Supermicro SYS-5039MS-H12TRF/X11SSE-F, BIOS 2.1a 03/08/2018 [ 248.865905] Call Trace: [ 248.865910] dump_stack+0xd6/0x185 [ 248.865911] ? show_regs_print_info+0xb/0xb [ 248.865913] ? printk+0x9c/0xc3 [ 248.865915] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 248.865919] print_address_description+0x6f/0x270 [ 248.865920] kasan_report+0x25b/0x380 [ 248.865922] ? _copy_to_user+0x5c/0x90 [ 248.865924] check_memory_region+0x137/0x190 [ 248.865925] kasan_check_read+0x11/0x20 [ 248.865927] _copy_to_user+0x5c/0x90 [ 248.865930] bpf_test_finish.isra.8+0x4f/0xc0 [ 248.865932] bpf_prog_test_run_skb+0x6a0/0xba0 [...] After scrubbing the BPF prog a bit from the noise, turns out it called bpf_skb_change_head() for the lwt_xmit prog with headroom of 2. Nothing wrong in that, however, this was run with repeat >> 0 in bpf_prog_test_run_skb() and the same skb thus keeps changing until the pskb_expand_head() called from skb_cow() keeps bailing out in atomic alloc context with -ENOMEM. So upon return we'll basically have 0 headroom left yet blindly do the __skb_push() of 14 bytes and keep copying data from there in bpf_test_finish() out of bounds. Fix to check if we have enough headroom and if pskb_expand_head() fails, bail out with error. Another bug independent of this fix (but related in triggering above) is that BPF_PROG_TEST_RUN should be reworked to reset the skb/xdp buffer to it's original state from input as otherwise repeating the same test in a loop won't work for benchmarking when underlying input buffer is getting changed by the prog each time and reused for the next run leading to unexpected results. Fixes: 1cf1cae963c2 ("bpf: introduce BPF_PROG_TEST_RUN command") Reported-by: syzbot+709412e651e55ed96498@syzkaller.appspotmail.com Reported-by: syzbot+54f39d6ab58f39720a55@syzkaller.appspotmail.com Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov [connoro: drop test_verifier.c changes not applicable to 4.14] Signed-off-by: Connor O'Brien Signed-off-by: Greg Kroah-Hartman

selftests/bpf: Enlarge select() timeout for test_maps

2021-09-22T09:45:31Z

[ Upstream commit 2d82d73da35b72b53fe0d96350a2b8d929d07e42 ] 0Day robot observed that it's easily timeout on a heavy load host. ------------------- # selftests: bpf: test_maps # Fork 1024 tasks to 'test_update_delete' # Fork 1024 tasks to 'test_update_delete' # Fork 100 tasks to 'test_hashmap' # Fork 100 tasks to 'test_hashmap_percpu' # Fork 100 tasks to 'test_hashmap_sizes' # Fork 100 tasks to 'test_hashmap_walk' # Fork 100 tasks to 'test_arraymap' # Fork 100 tasks to 'test_arraymap_percpu' # Failed sockmap unexpected timeout not ok 3 selftests: bpf: test_maps # exit=1 # selftests: bpf: test_lru_map # nr_cpus:8 ------------------- Since this test will be scheduled by 0Day to a random host that could have only a few cpus(2-8), enlarge the timeout to avoid a false NG report. In practice, i tried to pin it to only one cpu by 'taskset 0x01 ./test_maps', and knew 10S is likely enough, but i still perfer to a larger value 30. Reported-by: kernel test robot Signed-off-by: Li Zhijian Signed-off-by: Alexei Starovoitov Acked-by: Song Liu Link: https://lore.kernel.org/bpf/20210820015556.23276-2-lizhijian@cn.fujitsu.com Signed-off-by: Sasha Levin

selftests/bpf: make 'dubious pointer arithmetic' test useful

2021-06-10T10:43:53Z

commit 31e95b61e172144bb2b626a291db1bdc0769275b upstream. mostly revert the previous workaround and make 'dubious pointer arithmetic' test useful again. Use (ptr - ptr) << const instead of ptr << const to generate large scalar. The rest stays as before commit 2b36047e7889. Fixes: 2b36047e7889 ("selftests/bpf: fix test_align") Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann [fllinden@amazon.com: adjust for 4.14 (no liveness of regs in output)] Signed-off-by: Frank van der Linden Signed-off-by: Greg Kroah-Hartman

selftests/bpf: fix test_align

2021-06-10T10:43:53Z

commit 2b36047e7889b7efee22c11e17f035f721855731 upstream. since commit 82abbf8d2fc4 the verifier rejects the bit-wise arithmetic on pointers earlier. The test 'dubious pointer arithmetic' now has less output to match on. Adjust it. Fixes: 82abbf8d2fc4 ("bpf: do not allow root to mangle valid pointers") Reported-by: kernel test robot Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Signed-off-by: Greg Kroah-Hartman

bpf: do not allow root to mangle valid pointers

2021-06-10T10:43:52Z

commit 82abbf8d2fc46d79611ab58daa7c608df14bb3ee upstream. Do not allow root to convert valid pointers into unknown scalars. In particular disallow: ptr &= reg ptr <<= reg ptr += ptr and explicitly allow: ptr -= ptr since pkt_end - pkt == length 1. This minimizes amount of address leaks root can do. In the future may need to further tighten the leaks with kptr_restrict. 2. If program has such pointer math it's likely a user mistake and when verifier complains about it right away instead of many instructions later on invalid memory access it's easier for users to fix their progs. 3. when register holding a pointer cannot change to scalar it allows JITs to optimize better. Like 32-bit archs could use single register for pointers instead of a pair required to hold 64-bit scalars. 4. reduces architecture dependent behavior. Since code: r1 = r10; r1 &= 0xff; if (r1 ...) will behave differently arm64 vs x64 and offloaded vs native. A significant chunk of ptr mangling was allowed by commit f1174f77b50c ("bpf/verifier: rework value tracking") yet some of it was allowed even earlier. Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann [fllinden@amazon.com: backport to 4.14] Signed-off-by: Frank van der Linden Signed-off-by: Greg Kroah-Hartman

bpf: Update selftests to reflect new error states

2021-06-10T10:43:52Z

commit d7a5091351756d0ae8e63134313c455624e36a13 upstream. Update various selftest error messages: * The 'Rx tried to sub from different maps, paths, or prohibited types' is reworked into more specific/differentiated error messages for better guidance. * The change into 'value -4294967168 makes map_value pointer be out of bounds' is due to moving the mixed bounds check into the speculation handling and thus occuring slightly later than above mentioned sanity check. * The change into 'math between map_value pointer and register with unbounded min value' is similarly due to register sanity check coming before the mixed bounds check. * The case of 'map access: known scalar += value_ptr from different maps' now loads fine given masks are the same from the different paths (despite max map value size being different). Signed-off-by: Daniel Borkmann Reviewed-by: John Fastabend Acked-by: Alexei Starovoitov [fllinden@amazon.com - 4.14 backport, account for split test_verifier and different / missing tests] Signed-off-by: Frank van der Linden Signed-off-by: Greg Kroah-Hartman

bpf, selftests: Fix up some test_verifier cases for unprivileged

2021-06-10T10:43:52Z

commit 0a13e3537ea67452d549a6a80da3776d6b7dedb3 upstream. Fix up test_verifier error messages for the case where the original error message changed, or for the case where pointer alu errors differ between privileged and unprivileged tests. Also, add alternative tests for keeping coverage of the original verifier rejection error message (fp alu), and newly reject map_ptr += rX where rX == 0 given we now forbid alu on these types for unprivileged. All test_verifier cases pass after the change. The test case fixups were kept separate to ease backporting of core changes. Signed-off-by: Piotr Krysiuk Co-developed-by: Daniel Borkmann Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov [fllinden@amazon.com: backport to 4.14, skipping non-existent tests] Signed-off-by: Frank van der Linden Signed-off-by: Greg Kroah-Hartman

bpf: fix up selftests after backports were fixed

2021-05-22T08:57:13Z

After the backport of the changes to fix CVE 2019-7308, the selftests also need to be fixed up, as was done originally in mainline 80c9b2fae87b ("bpf: add various test cases to selftests"). 4.14 commit 03f11a51a19 ("bpf: Fix selftests are changes for CVE 2019-7308") did that, but since there was an error in the backport, some selftests did not change output. So, add them now that this error has been fixed, and their output has actually changed as expected. This adds the rest of the changed test outputs from 80c9b2fae87b. Fixes: 03f11a51a19 ("bpf: Fix selftests are changes for CVE 2019-7308") Signed-off-by: Frank van der Linden Signed-off-by: Greg Kroah-Hartman