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linux/tools/testing/selftests/bpf
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Daniel Borkmann ca36960211 bpf: allow xadd only on aligned memory 
The requirements around atomic_add() / atomic64_add() resp. their
JIT implementations differ across architectures. E.g. while x86_64
seems just fine with BPF's xadd on unaligned memory, on arm64 it
triggers via interpreter but also JIT the following crash:

  [  830.864985] Unable to handle kernel paging request at virtual address ffff8097d7ed6703
  [...]
  [  830.916161] Internal error: Oops: 96000021 [#1] SMP
  [  830.984755] CPU: 37 PID: 2788 Comm: test_verifier Not tainted 4.16.0-rc2+ #8
  [  830.991790] Hardware name: Huawei TaiShan 2280 /BC11SPCD, BIOS 1.29 07/17/2017
  [  830.998998] pstate: 80400005 (Nzcv daif +PAN -UAO)
  [  831.003793] pc : __ll_sc_atomic_add+0x4/0x18
  [  831.008055] lr : ___bpf_prog_run+0x1198/0x1588
  [  831.012485] sp : ffff00001ccabc20
  [  831.015786] x29: ffff00001ccabc20 x28: ffff8017d56a0f00
  [  831.021087] x27: 0000000000000001 x26: 0000000000000000
  [  831.026387] x25: 000000c168d9db98 x24: 0000000000000000
  [  831.031686] x23: ffff000008203878 x22: ffff000009488000
  [  831.036986] x21: ffff000008b14e28 x20: ffff00001ccabcb0
  [  831.042286] x19: ffff0000097b5080 x18: 0000000000000a03
  [  831.047585] x17: 0000000000000000 x16: 0000000000000000
  [  831.052885] x15: 0000ffffaeca8000 x14: 0000000000000000
  [  831.058184] x13: 0000000000000000 x12: 0000000000000000
  [  831.063484] x11: 0000000000000001 x10: 0000000000000000
  [  831.068783] x9 : 0000000000000000 x8 : 0000000000000000
  [  831.074083] x7 : 0000000000000000 x6 : 000580d428000000
  [  831.079383] x5 : 0000000000000018 x4 : 0000000000000000
  [  831.084682] x3 : ffff00001ccabcb0 x2 : 0000000000000001
  [  831.089982] x1 : ffff8097d7ed6703 x0 : 0000000000000001
  [  831.095282] Process test_verifier (pid: 2788, stack limit = 0x0000000018370044)
  [  831.102577] Call trace:
  [  831.105012]  __ll_sc_atomic_add+0x4/0x18
  [  831.108923]  __bpf_prog_run32+0x4c/0x70
  [  831.112748]  bpf_test_run+0x78/0xf8
  [  831.116224]  bpf_prog_test_run_xdp+0xb4/0x120
  [  831.120567]  SyS_bpf+0x77c/0x1110
  [  831.123873]  el0_svc_naked+0x30/0x34
  [  831.127437] Code: 97fffe97 17ffffec 00000000 f9800031 (885f7c31)

Reason for this is because memory is required to be aligned. In
case of BPF, we always enforce alignment in terms of stack access,
but not when accessing map values or packet data when the underlying
arch (e.g. arm64) has CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS set.

xadd on packet data that is local to us anyway is just wrong, so
forbid this case entirely. The only place where xadd makes sense in
fact are map values; xadd on stack is wrong as well, but it's been
around for much longer. Specifically enforce strict alignment in case
of xadd, so that we handle this case generically and avoid such crashes
in the first place.

Fixes: 17a5267067 ("bpf: verifier (add verifier core)")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-02-23 14:33:39 -08:00
..
gnu selftests/bpf: get rid of -D__x86_64__ 2017-05-03 09:51:25 -04:00
include/uapi/linux License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
.gitignore selftests/bpf: update gitignore with test_libbpf_open 2018-02-22 01:41:18 +01:00
bpf_endian.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
bpf_helpers.h bpf: add selftest for tcpbpf 2018-01-25 16:41:15 -08:00
bpf_util.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cgroup_helpers.c bpf: move cgroup_helpers from samples/bpf/ to tools/testing/selftesting/bpf/ 2017-11-05 23:26:51 +09:00
cgroup_helpers.h bpf: move cgroup_helpers from samples/bpf/ to tools/testing/selftesting/bpf/ 2017-11-05 23:26:51 +09:00
config selftests/bpf: add netdevsim to config 2017-12-19 01:35:12 +01:00
dev_cgroup.c selftests/bpf: add a test for device cgroup controller 2017-11-05 23:26:51 +09:00
Makefile selftests/bpf: add selftest that use test_libbpf_open 2018-02-09 00:25:12 +01:00
sample_map_ret0.c selftest/bpf: extend the offload test with map checks 2018-01-18 22:54:26 +01:00
sample_ret0.c selftests/bpf: add offload test based on netdevsim 2017-12-03 00:27:58 +01:00
sockmap_parse_prog.c selftests/bpf: remove useless bpf_trace_printk 2017-11-01 12:06:46 +09:00
sockmap_verdict_prog.c selftests/bpf: remove useless bpf_trace_printk 2017-11-01 12:06:46 +09:00
tcp_client.py bpf: add selftest for tcpbpf 2018-01-25 16:41:15 -08:00
tcp_server.py bpf: add selftest for tcpbpf 2018-01-25 16:41:15 -08:00
test_align.c selftests/bpf: make 'dubious pointer arithmetic' test useful 2018-01-24 10:39:58 +01:00
test_dev_cgroup.c selftests/bpf: fix test_dev_cgroup 2018-01-23 18:42:12 +01:00
test_iptunnel_common.h selftests/bpf: add a test for basic XDP functionality 2017-04-01 12:45:57 -07:00
test_kmod.sh selftests: bpf: test_kmod.sh: check the module path before insmod 2018-02-08 00:24:55 +01:00
test_l4lb_noinline.c selftests/bpf: add bpf_call test 2017-12-17 20:34:36 +01:00
test_l4lb.c bpf: Move endianness BPF helpers out of bpf_util.h 2017-05-01 12:43:49 -07:00
test_libbpf_open.c selftests/bpf: add test program for loading BPF ELF files 2018-02-09 00:24:38 +01:00
test_libbpf.sh selftests/bpf: add selftest that use test_libbpf_open 2018-02-09 00:25:12 +01:00
test_lpm_map.c tools/bpf: add a multithreaded stress test in bpf selftests test_lpm_map 2018-01-26 17:06:22 -08:00
test_lru_map.c bpf: lru: Lower the PERCPU_NR_SCANS from 16 to 4 2017-04-17 13:55:52 -04:00
test_maps.c selftests/bpf/test_maps: exit child process without error in ENOMEM case 2018-02-22 15:21:26 +01:00
test_obj_id.c bpf: Fix test_obj_id.c for llvm 5.0 2017-06-09 15:15:11 -04:00
test_offload.py selftests/bpf: check for chain-non-0 extack message 2018-01-25 21:23:09 -05:00
test_pkt_access.c selftests/bpf: fix broken build due to types.h 2017-05-17 18:45:14 -04:00
test_pkt_md_access.c bpf: fix selftest/bpf/test_pkt_md_access on s390x 2017-08-07 10:06:27 -07:00
test_progs.c tools/bpf: add a bpf selftest for stacktrace 2018-01-06 23:52:23 +01:00
test_stacktrace_map.c tools/bpf: add a bpf selftest for stacktrace 2018-01-06 23:52:23 +01:00
test_tag.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
test_tcp_estats.c selftests/bpf: add a test case to check verifier pointer arithmetic 2017-05-03 09:51:25 -04:00
test_tcpbpf_kern.c selftests/bpf: tcpbpf_kern: use in6_* macros from glibc 2018-02-22 01:19:37 +01:00
test_tcpbpf_user.c bpf: add selftest for tcpbpf 2018-01-25 16:41:15 -08:00
test_tcpbpf.h bpf: add selftest for tcpbpf 2018-01-25 16:41:15 -08:00
test_tracepoint.c bpf/tracing: add a bpf test for new ioctl query interface 2017-12-12 08:46:40 -08:00
test_verifier_log.c tools/bpf: adjust rlimit RLIMIT_MEMLOCK for test_verifier_log 2017-11-30 19:55:18 +01:00
test_verifier.c bpf: allow xadd only on aligned memory 2018-02-23 14:33:39 -08:00
test_xdp_meta.c bpf: improve selftests and add tests for meta pointer 2017-09-26 13:36:44 -07:00
test_xdp_meta.sh tools/bpf: fix batch-mode test failure of test_xdp_redirect.sh 2018-02-06 11:34:42 +01:00
test_xdp_noinline.c selftests/bpf: add xdp noinline test 2017-12-17 20:34:36 +01:00
test_xdp_redirect.c selftests: bpf: add a test for XDP redirect 2017-08-08 18:12:50 -07:00
test_xdp_redirect.sh tools/bpf: fix batch-mode test failure of test_xdp_redirect.sh 2018-02-06 11:34:42 +01:00
test_xdp.c selftests: bpf: Use bpf_endian.h in test_xdp.c 2017-05-02 07:52:01 -07:00