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2018-12-10bpf: relax verifier restriction on BPF_MOV | BPF_ALUJiong Wang
Currently, the destination register is marked as unknown for 32-bit sub-register move (BPF_MOV | BPF_ALU) whenever the source register type is SCALAR_VALUE. This is too conservative that some valid cases will be rejected. Especially, this may turn a constant scalar value into unknown value that could break some assumptions of verifier. For example, test_l4lb_noinline.c has the following C code: struct real_definition *dst 1: if (!get_packet_dst(&dst, &pckt, vip_info, is_ipv6)) 2: return TC_ACT_SHOT; 3: 4: if (dst->flags & F_IPV6) { get_packet_dst is responsible for initializing "dst" into valid pointer and return true (1), otherwise return false (0). The compiled instruction sequence using alu32 will be: 412: (54) (u32) r7 &= (u32) 1 413: (bc) (u32) r0 = (u32) r7 414: (95) exit insn 413, a BPF_MOV | BPF_ALU, however will turn r0 into unknown value even r7 contains SCALAR_VALUE 1. This causes trouble when verifier is walking the code path that hasn't initialized "dst" inside get_packet_dst, for which case 0 is returned and we would then expect verifier concluding line 1 in the above C code pass the "if" check, therefore would skip fall through path starting at line 4. Now, because r0 returned from callee has became unknown value, so verifier won't skip analyzing path starting at line 4 and "dst->flags" requires dereferencing the pointer "dst" which actually hasn't be initialized for this path. This patch relaxed the code marking sub-register move destination. For a SCALAR_VALUE, it is safe to just copy the value from source then truncate it into 32-bit. A unit test also included to demonstrate this issue. This test will fail before this patch. This relaxation could let verifier skipping more paths for conditional comparison against immediate. It also let verifier recording a more accurate/strict value for one register at one state, if this state end up with going through exit without rejection and it is used for state comparison later, then it is possible an inaccurate/permissive value is better. So the real impact on verifier processed insn number is complex. But in all, without this fix, valid program could be rejected. >From real benchmarking on kernel selftests and Cilium bpf tests, there is no impact on processed instruction number when tests ares compiled with default compilation options. There is slightly improvements when they are compiled with -mattr=+alu32 after this patch. Also, test_xdp_noinline/-mattr=+alu32 now passed verification. It is rejected before this fix. Insn processed before/after this patch: default -mattr=+alu32 Kernel selftest === test_xdp.o 371/371 369/369 test_l4lb.o 6345/6345 5623/5623 test_xdp_noinline.o 2971/2971 rejected/2727 test_tcp_estates.o 429/429 430/430 Cilium bpf === bpf_lb-DLB_L3.o: 2085/2085 1685/1687 bpf_lb-DLB_L4.o: 2287/2287 1986/1982 bpf_lb-DUNKNOWN.o: 690/690 622/622 bpf_lxc.o: 95033/95033 N/A bpf_netdev.o: 7245/7245 N/A bpf_overlay.o: 2898/2898 3085/2947 NOTE: - bpf_lxc.o and bpf_netdev.o compiled by -mattr=+alu32 are rejected by verifier due to another issue inside verifier on supporting alu32 binary. - Each cilium bpf program could generate several processed insn number, above number is sum of them. v1->v2: - Restrict the change on SCALAR_VALUE. - Update benchmark numbers on Cilium bpf tests. Signed-off-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-12-09Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Several conflicts, seemingly all over the place. I used Stephen Rothwell's sample resolutions for many of these, if not just to double check my own work, so definitely the credit largely goes to him. The NFP conflict consisted of a bug fix (moving operations past the rhashtable operation) while chaning the initial argument in the function call in the moved code. The net/dsa/master.c conflict had to do with a bug fix intermixing of making dsa_master_set_mtu() static with the fixing of the tagging attribute location. cls_flower had a conflict because the dup reject fix from Or overlapped with the addition of port range classifiction. __set_phy_supported()'s conflict was relatively easy to resolve because Andrew fixed it in both trees, so it was just a matter of taking the net-next copy. Or at least I think it was :-) Joe Stringer's fix to the handling of netns id 0 in bpf_sk_lookup() intermixed with changes on how the sdif and caller_net are calculated in these code paths in net-next. The remaining BPF conflicts were largely about the addition of the __bpf_md_ptr stuff in 'net' overlapping with adjustments and additions to the relevant data structure where the MD pointer macros are used. Signed-off-by: David S. Miller <davem@davemloft.net>
2018-12-07selftests: bpf: update testcases for BPF_ALU | BPF_ARSHJiong Wang
"arsh32 on imm" and "arsh32 on reg" now are accepted. Also added two new testcases to make sure arsh32 won't be treated as arsh64 during interpretation or JIT code-gen for which case the high bits will be moved into low halve that the testcases could catch them. Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-12-04bpf: improve verifier branch analysisAlexei Starovoitov
pathological bpf programs may try to force verifier to explode in the number of branch states: 20: (d5) if r1 s<= 0x24000028 goto pc+0 21: (b5) if r0 <= 0xe1fa20 goto pc+2 22: (d5) if r1 s<= 0x7e goto pc+0 23: (b5) if r0 <= 0xe880e000 goto pc+0 24: (c5) if r0 s< 0x2100ecf4 goto pc+0 25: (d5) if r1 s<= 0xe880e000 goto pc+1 26: (c5) if r0 s< 0xf4041810 goto pc+0 27: (d5) if r1 s<= 0x1e007e goto pc+0 28: (b5) if r0 <= 0xe86be000 goto pc+0 29: (07) r0 += 16614 30: (c5) if r0 s< 0x6d0020da goto pc+0 31: (35) if r0 >= 0x2100ecf4 goto pc+0 Teach verifier to recognize always taken and always not taken branches. This analysis is already done for == and != comparison. Expand it to all other branches. It also helps real bpf programs to be verified faster: before after bpf_lb-DLB_L3.o 2003 1940 bpf_lb-DLB_L4.o 3173 3089 bpf_lb-DUNKNOWN.o 1080 1065 bpf_lxc-DDROP_ALL.o 29584 28052 bpf_lxc-DUNKNOWN.o 36916 35487 bpf_netdev.o 11188 10864 bpf_overlay.o 6679 6643 bpf_lcx_jit.o 39555 38437 Reported-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Edward Cree <ecree@solarflare.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-12-03bpf: allow BPF read access to qdisc pkt_lenPetar Penkov
The pkt_len field in qdisc_skb_cb stores the skb length as it will appear on the wire after segmentation. For byte accounting, this value is more accurate than skb->len. It is computed on entry to the TC layer, so only valid there. Allow read access to this field from BPF tc classifier and action programs. The implementation is analogous to tc_classid, aside from restricting to read access. To distinguish it from skb->len and self-describe export as wire_len. Changes v1->v2 - Rename pkt_len to wire_len Signed-off-by: Petar Penkov <ppenkov@google.com> Signed-off-by: Vlad Dumitrescu <vladum@google.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-11-30bpf: Apply F_NEEDS_EFFICIENT_UNALIGNED_ACCESS to more ACCEPT test cases.David Miller
If a testcase has alignment problems but is expected to be ACCEPT, verify it using F_NEEDS_EFFICIENT_UNALIGNED_ACCESS too. Maybe in the future if we add some architecture specific code to elide the unaligned memory access warnings during the test, we can execute these as well. Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-11-30bpf: Make more use of 'any' alignment in test_verifier.cDavid Miller
Use F_NEEDS_EFFICIENT_UNALIGNED_ACCESS in more tests where the expected result is REJECT. Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-11-30bpf: Adjust F_NEEDS_EFFICIENT_UNALIGNED_ACCESS handling in test_verifier.cDavid Miller
Make it set the flag argument to bpf_verify_program() which will relax the alignment restrictions. Now all such test cases will go properly through the verifier even on inefficient unaligned access architectures. On inefficient unaligned access architectures do not try to run such programs, instead mark the test case as passing but annotate the result similarly to how it is done now in the presence of this flag. So, we get complete full coverage for all REJECT test cases, and at least verifier level coverage for ACCEPT test cases. Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-11-30bpf: Add BPF_F_ANY_ALIGNMENT.David Miller
Often we want to write tests cases that check things like bad context offset accesses. And one way to do this is to use an odd offset on, for example, a 32-bit load. This unfortunately triggers the alignment checks first on platforms that do not set CONFIG_EFFICIENT_UNALIGNED_ACCESS. So the test case see the alignment failure rather than what it was testing for. It is often not completely possible to respect the original intention of the test, or even test the same exact thing, while solving the alignment issue. Another option could have been to check the alignment after the context and other validations are performed by the verifier, but that is a non-trivial change to the verifier. Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-11-30bpf: Fix verifier log string check for bad alignment.David Miller
The message got changed a lot time ago. This was responsible for 36 test case failures on sparc64. Fixes: f1174f77b50c ("bpf/verifier: rework value tracking") Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-11-30bpf: Fix verifier log string check for bad alignment.David Miller
The message got changed a lot time ago. This was responsible for 36 test case failures on sparc64. Fixes: f1174f77b50c ("bpf/verifier: rework value tracking") Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-11-28Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Trivial conflict in net/core/filter.c, a locally computed 'sdif' is now an argument to the function. Signed-off-by: David S. Miller <davem@davemloft.net>
2018-11-22bpf: add skb->tstamp r/w access from tc clsact and cg skb progsVlad Dumitrescu
This could be used to rate limit egress traffic in concert with a qdisc which supports Earliest Departure Time, such as FQ. Write access from cg skb progs only with CAP_SYS_ADMIN, since the value will be used by downstream qdiscs. It might make sense to relax this. Changes v1 -> v2: - allow access from cg skb, write only with CAP_SYS_ADMIN Signed-off-by: Vlad Dumitrescu <vladum@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-11-16bpf: fix off-by-one error in adjust_subprog_startsEdward Cree
When patching in a new sequence for the first insn of a subprog, the start of that subprog does not change (it's the first insn of the sequence), so adjust_subprog_starts should check start <= off (rather than < off). Also added a test to test_verifier.c (it's essentially the syz reproducer). Fixes: cc8b0b92a169 ("bpf: introduce function calls (function boundaries)") Reported-by: syzbot+4fc427c7af994b0948be@syzkaller.appspotmail.com Signed-off-by: Edward Cree <ecree@solarflare.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-11-10selftests/bpf: Test narrow loads with off > 0 in test_verifierAndrey Ignatov
Test the following narrow loads in test_verifier for context __sk_buff: * off=1, size=1 - ok; * off=2, size=1 - ok; * off=3, size=1 - ok; * off=0, size=2 - ok; * off=1, size=2 - fail; * off=0, size=2 - ok; * off=3, size=2 - fail. Signed-off-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-10-31bpf: test make sure to run unpriv test cases in test_verifierDaniel Borkmann
Right now unprivileged tests are never executed as a BPF test run, only loaded. Allow for running them as well so that we can check the outcome and probe for regressions. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-10-31bpf: add various test cases to test_verifierDaniel Borkmann
Add some more map related test cases to test_verifier kselftest to improve test coverage. Summary: 1012 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-10-25bpf: disallow direct packet access for unpriv in cg_skbDaniel Borkmann
Commit b39b5f411dcf ("bpf: add cg_skb_is_valid_access for BPF_PROG_TYPE_CGROUP_SKB") added support for returning pkt pointers for direct packet access. Given this program type is allowed for both unprivileged and privileged users, we shouldn't allow unprivileged ones to use it, e.g. besides others one reason would be to avoid any potential speculation on the packet test itself, thus guard this for root only. Fixes: b39b5f411dcf ("bpf: add cg_skb_is_valid_access for BPF_PROG_TYPE_CGROUP_SKB") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-10-25bpf: fix test suite to enable all unpriv program typesDaniel Borkmann
Given BPF_PROG_TYPE_CGROUP_SKB program types are also valid in an unprivileged setting, lets not omit these tests and potentially have issues fall through the cracks. Make this more obvious by adding a small test_as_unpriv() helper. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-10-20bpf, verifier: fix register type dump in xadd and stDaniel Borkmann
Using reg_type_str[insn->dst_reg] is incorrect since insn->dst_reg contains the register number but not the actual register type. Add a small reg_state() helper and use it to get to the type. Also fix up the test_verifier test cases that have an incorrect errstr. Fixes: 9d2be44a7f33 ("bpf: Reuse canonical string formatter for ctx errs") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-10-19bpf: add tests for direct packet access from CGROUP_SKBSong Liu
Tests are added to make sure CGROUP_SKB cannot access: tc_classid, data_meta, flow_keys and can read and write: mark, prority, and cb[0-4] and can read other fields. To make selftest with skb->sk work, a dummy sk is added in bpf_prog_test_run_skb(). Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-10-09selftests/bpf: test_verifier, check bpf_map_lookup_elem access in bpf progPrashant Bhole
map_lookup_elem isn't supported by certain map types like: - BPF_MAP_TYPE_PROG_ARRAY - BPF_MAP_TYPE_STACK_TRACE - BPF_MAP_TYPE_XSKMAP - BPF_MAP_TYPE_SOCKMAP/BPF_MAP_TYPE_SOCKHASH Let's add verfier tests to check whether verifier prevents bpf_map_lookup_elem call on above programs from bpf program. Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-10-09selftests/bpf: test_verifier, change names of fixup mapsPrashant Bhole
Currently fixup map are named like fixup_map1, fixup_map2, and so on. As suggested by Alexei let's change change map names such that we can identify map type by looking at the name. This patch is basically a find and replace change: fixup_map1 -> fixup_map_hash_8b fixup_map2 -> fixup_map_hash_48b fixup_map3 -> fixup_map_hash_16b fixup_map4 -> fixup_map_array_48b Suggested-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-10-03selftests/bpf: Add tests for reference trackingJoe Stringer
reference tracking: leak potential reference reference tracking: leak potential reference on stack reference tracking: leak potential reference on stack 2 reference tracking: zero potential reference reference tracking: copy and zero potential references reference tracking: release reference without check reference tracking: release reference reference tracking: release reference twice reference tracking: release reference twice inside branch reference tracking: alloc, check, free in one subbranch reference tracking: alloc, check, free in both subbranches reference tracking in call: free reference in subprog reference tracking in call: free reference in subprog and outside reference tracking in call: alloc & leak reference in subprog reference tracking in call: alloc in subprog, release outside reference tracking in call: sk_ptr leak into caller stack reference tracking in call: sk_ptr spill into caller stack reference tracking: allow LD_ABS reference tracking: forbid LD_ABS while holding reference reference tracking: allow LD_IND reference tracking: forbid LD_IND while holding reference reference tracking: check reference or tail call reference tracking: release reference then tail call reference tracking: leak possible reference over tail call reference tracking: leak checked reference over tail call reference tracking: mangle and release sock_or_null reference tracking: mangle and release sock reference tracking: access member reference tracking: write to member reference tracking: invalid 64-bit access of member reference tracking: access after release reference tracking: direct access for lookup unpriv: spill/fill of different pointers stx - ctx and sock unpriv: spill/fill of different pointers stx - leak sock unpriv: spill/fill of different pointers stx - sock and ctx (read) unpriv: spill/fill of different pointers stx - sock and ctx (write) Signed-off-by: Joe Stringer <joe@wand.net.nz> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-10-03selftests/bpf: Generalize dummy program typesJoe Stringer
Don't hardcode the dummy program types to SOCKET_FILTER type, as this prevents testing bpf_tail_call in conjunction with other program types. Instead, use the program type specified in the test case. Signed-off-by: Joe Stringer <joe@wand.net.nz> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-10-03bpf: Reuse canonical string formatter for ctx errsJoe Stringer
The array "reg_type_str" provides canonical formatting of register types, however a couple of places would previously check whether a register represented the context and write the name "context" directly. An upcoming commit will add another pointer type to these statements, so to provide more accurate error messages in the verifier, update these error messages to use "reg_type_str" instead. Signed-off-by: Joe Stringer <joe@wand.net.nz> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-10-03bpf: Simplify ptr_min_max_vals adjustmentJoe Stringer
An upcoming commit will add another two pointer types that need very similar behaviour, so generalise this function now. Signed-off-by: Joe Stringer <joe@wand.net.nz> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-10-01selftests/bpf: add verifier per-cpu cgroup storage testsRoman Gushchin
This commits adds verifier tests covering per-cpu cgroup storage functionality. There are 6 new tests, which are exactly the same as for shared cgroup storage, but do use per-cpu cgroup storage map. Expected output: $ ./test_verifier #0/u add+sub+mul OK #0/p add+sub+mul OK ... #286/p invalid cgroup storage access 6 OK #287/p valid per-cpu cgroup storage access OK #288/p invalid per-cpu cgroup storage access 1 OK #289/p invalid per-cpu cgroup storage access 2 OK #290/p invalid per-cpu cgroup storage access 3 OK #291/p invalid per-cpu cgroup storage access 4 OK #292/p invalid per-cpu cgroup storage access 5 OK #293/p invalid per-cpu cgroup storage access 6 OK #294/p multiple registers share map_lookup_elem result OK ... #662/p mov64 src == dst OK #663/p mov64 src != dst OK Summary: 914 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: Song Liu <songliubraving@fb.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-08-11bpf: Refactor ARRAY_SIZE macro to bpf_util.hMartin KaFai Lau
This patch refactors the ARRAY_SIZE macro to bpf_util.h. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-08-07Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller
Daniel Borkmann says: ==================== pull-request: bpf-next 2018-08-07 The following pull-request contains BPF updates for your *net-next* tree. The main changes are: 1) Add cgroup local storage for BPF programs, which provides a fast accessible memory for storing various per-cgroup data like number of transmitted packets, etc, from Roman. 2) Support bpf_get_socket_cookie() BPF helper in several more program types that have a full socket available, from Andrey. 3) Significantly improve the performance of perf events which are reported from BPF offload. Also convert a couple of BPF AF_XDP samples overto use libbpf, both from Jakub. 4) seg6local LWT provides the End.DT6 action, which allows to decapsulate an outer IPv6 header containing a Segment Routing Header. Adds this action now to the seg6local BPF interface, from Mathieu. 5) Do not mark dst register as unbounded in MOV64 instruction when both src and dst register are the same, from Arthur. 6) Define u_smp_rmb() and u_smp_wmb() to their respective barrier instructions on arm64 for the AF_XDP sample code, from Brian. 7) Convert the tcp_client.py and tcp_server.py BPF selftest scripts over from Python 2 to Python 3, from Jeremy. 8) Enable BTF build flags to the BPF sample code Makefile, from Taeung. 9) Remove an unnecessary rcu_read_lock() in run_lwt_bpf(), from Taehee. 10) Several improvements to the README.rst from the BPF documentation to make it more consistent with RST format, from Tobin. 11) Replace all occurrences of strerror() by calls to strerror_r() in libbpf and fix a FORTIFY_SOURCE build error along with it, from Thomas. 12) Fix a bug in bpftool's get_btf() function to correctly propagate an error via PTR_ERR(), from Yue. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-03selftests/bpf: fix a typo in map in map testRoman Gushchin
Commit fbeb1603bf4e ("bpf: verifier: MOV64 don't mark dst reg unbounded") revealed a typo in commit fb30d4b71214 ("bpf: Add tests for map-in-map"): BPF_MOV64_REG(BPF_REG_0, 0) was used instead of BPF_MOV64_IMM(BPF_REG_0, 0). I've noticed the problem by running bpf kselftests. Fixes: fb30d4b71214 ("bpf: Add tests for map-in-map") Signed-off-by: Roman Gushchin <guro@fb.com> Cc: Martin KaFai Lau <kafai@fb.com> Cc: Arthur Fabre <afabre@cloudflare.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-08-03selftests/bpf: add verifier cgroup storage testsRoman Gushchin
Add the following verifier tests to cover the cgroup storage functionality: 1) valid access to the cgroup storage 2) invalid access: use regular hashmap instead of cgroup storage map 3) invalid access: use invalid map fd 4) invalid access: try access memory after the cgroup storage 5) invalid access: try access memory before the cgroup storage 6) invalid access: call get_local_storage() with non-zero flags For tests 2)-6) check returned error strings. Expected output: $ ./test_verifier #0/u add+sub+mul OK #0/p add+sub+mul OK #1/u DIV32 by 0, zero check 1 OK ... #280/p valid cgroup storage access OK #281/p invalid cgroup storage access 1 OK #282/p invalid cgroup storage access 2 OK #283/p invalid per-cgroup storage access 3 OK #284/p invalid cgroup storage access 4 OK #285/p invalid cgroup storage access 5 OK ... #649/p pass modified ctx pointer to helper, 2 OK #650/p pass modified ctx pointer to helper, 3 OK Summary: 901 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Roman Gushchin <guro@fb.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-07-31bpf: verifier: MOV64 don't mark dst reg unboundedArthur Fabre
When check_alu_op() handles a BPF_MOV64 between two registers, it calls check_reg_arg(DST_OP) on the dst register, marking it as unbounded. If the src and dst register are the same, this marks the src as unbounded, which can lead to unexpected errors for further checks that rely on bounds info. For example: BPF_MOV64_IMM(BPF_REG_2, 0), BPF_MOV64_REG(BPF_REG_2, BPF_REG_2), BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_2), BPF_MOV64_IMM(BPF_REG_0, 0), BPF_EXIT_INSN(), Results in: "math between ctx pointer and register with unbounded min value is not allowed" check_alu_op() now uses check_reg_arg(DST_OP_NO_MARK), and MOVs that need to mark the dst register (MOVIMM, MOV32) do so. Added a test case for MOV64 dst == src, and dst != src. Signed-off-by: Arthur Fabre <afabre@cloudflare.com> Acked-by: Edward Cree <ecree@solarflare.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-07-19bpf: test case to check whether src/dst regs got mangled by xaddDaniel Borkmann
We currently do not have such a test case in test_verifier selftests but it's important to test under bpf_jit_enable=1 to make sure JIT implementations do not mistakenly mess with src/dst reg for xadd/{w,dw}. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-07-11bpf: fix panic due to oob in bpf_prog_test_run_skbDaniel Borkmann
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 <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-06-07bpf: reject passing modified ctx to helper functionsDaniel Borkmann
As commit 28e33f9d78ee ("bpf: disallow arithmetic operations on context pointer") already describes, f1174f77b50c ("bpf/verifier: rework value tracking") removed the specific white-listed cases we had previously where we would allow for pointer arithmetic in order to further generalize it, and allow e.g. context access via modified registers. While the dereferencing of modified context pointers had been forbidden through 28e33f9d78ee, syzkaller did recently manage to trigger several KASAN splats for slab out of bounds access and use after frees by simply passing a modified context pointer to a helper function which would then do the bad access since verifier allowed it in adjust_ptr_min_max_vals(). Rejecting arithmetic on ctx pointer in adjust_ptr_min_max_vals() generally could break existing programs as there's a valid use case in tracing in combination with passing the ctx to helpers as bpf_probe_read(), where the register then becomes unknown at verification time due to adding a non-constant offset to it. An access sequence may look like the following: offset = args->filename; /* field __data_loc filename */ bpf_probe_read(&dst, len, (char *)args + offset); // args is ctx There are two options: i) we could special case the ctx and as soon as we add a constant or bounded offset to it (hence ctx type wouldn't change) we could turn the ctx into an unknown scalar, or ii) we generalize the sanity test for ctx member access into a small helper and assert it on the ctx register that was passed as a function argument. Fwiw, latter is more obvious and less complex at the same time, and one case that may potentially be legitimate in future for ctx member access at least would be for ctx to carry a const offset. Therefore, fix follows approach from ii) and adds test cases to BPF kselftests. Fixes: f1174f77b50c ("bpf/verifier: rework value tracking") Reported-by: syzbot+3d0b2441dbb71751615e@syzkaller.appspotmail.com Reported-by: syzbot+c8504affd4fdd0c1b626@syzkaller.appspotmail.com Reported-by: syzbot+e5190cb881d8660fb1a3@syzkaller.appspotmail.com Reported-by: syzbot+efae31b384d5badbd620@syzkaller.appspotmail.com Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Edward Cree <ecree@solarflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-06-03bpf: test case for map pointer poison with calls/branchesDaniel Borkmann
Add several test cases where the same or different map pointers originate from different paths in the program and execute a map lookup or tail call at a common location. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-24Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller
Alexei Starovoitov says: ==================== pull-request: bpf-next 2018-05-24 The following pull-request contains BPF updates for your *net-next* tree. The main changes are: 1) Björn Töpel cleans up AF_XDP (removes rebind, explicit cache alignment from uapi, etc). 2) David Ahern adds mtu checks to bpf_ipv{4,6}_fib_lookup() helpers. 3) Jesper Dangaard Brouer adds bulking support to ndo_xdp_xmit. 4) Jiong Wang adds support for indirect and arithmetic shifts to NFP 5) Martin KaFai Lau cleans up BTF uapi and makes the btf_header extensible. 6) Mathieu Xhonneux adds an End.BPF action to seg6local with BPF helpers allowing to edit/grow/shrink a SRH and apply on a packet generic SRv6 actions. 7) Sandipan Das adds support for bpf2bpf function calls in ppc64 JIT. 8) Yonghong Song adds BPF_TASK_FD_QUERY command for introspection of tracing events. 9) other misc fixes from Gustavo A. R. Silva, Sirio Balmelli, John Fastabend, and Magnus Karlsson ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-21Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
S390 bpf_jit.S is removed in net-next and had changes in 'net', since that code isn't used any more take the removal. TLS data structures split the TX and RX components in 'net-next', put the new struct members from the bug fix in 'net' into the RX part. The 'net-next' tree had some reworking of how the ERSPAN code works in the GRE tunneling code, overlapping with a one-line headroom calculation fix in 'net'. Overlapping changes in __sock_map_ctx_update_elem(), keep the bits that read the prog members via READ_ONCE() into local variables before using them. Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-18bpf: add sk_msg prog sk access tests to test_verifierJohn Fastabend
Add tests for BPF_PROG_TYPE_SK_MSG to test_verifier for read access to new sk fields. Signed-off-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-17selftests/bpf: check return value of fopen in test_verifier.cJesper Dangaard Brouer
Commit 0a6748740368 ("selftests/bpf: Only run tests if !bpf_disabled") forgot to check return value of fopen. This caused some confusion, when running test_verifier (from tools/testing/selftests/bpf/) on an older kernel (< v4.4) as it will simply seqfault. This fix avoids the segfault and prints an error, but allow program to continue. Given the sysctl was introduced in 1be7f75d1668 ("bpf: enable non-root eBPF programs"), we know that the running kernel cannot support unpriv, thus continue with unpriv_disabled = true. Fixes: 0a6748740368 ("selftests/bpf: Only run tests if !bpf_disabled") Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-14bpf: add ld64 imm test casesDaniel Borkmann
Add test cases where we combine semi-random imm values, mainly for testing JITs when they have different encoding options for 64 bit immediates in order to reduce resulting image size. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-03bpf: migrate ebpf ld_abs/ld_ind tests to test_verifierDaniel Borkmann
Remove all eBPF tests involving LD_ABS/LD_IND from test_bpf.ko. Reason is that the eBPF tests from test_bpf module do not go via BPF verifier and therefore any instruction rewrites from verifier cannot take place. Therefore, move them into test_verifier which runs out of user space, so that verfier can rewrite LD_ABS/LD_IND internally in upcoming patches. It will have the same effect since runtime tests are also performed from there. This also allows to finally unexport bpf_skb_vlan_{push,pop}_proto and keep it internal to core kernel. Additionally, also add further cBPF LD_ABS/LD_IND test coverage into test_bpf.ko suite. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-04-29tools/bpf: add a verifier test case for bpf_get_stack helper and ARSHYonghong Song
The test_verifier already has a few ARSH test cases. This patch adds a new test case which takes advantage of newly improved verifier behavior for bpf_get_stack and ARSH. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-04-24tools/bpf: add verifier tests for accesses to map valuesPaul Chaignon
This patch adds new test cases for accesses to map values from map helpers. Signed-off-by: Paul Chaignon <paul.chaignon@orange.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-03-19bpf: add verifier tests for BPF_PROG_TYPE_SK_MSGJohn Fastabend
Test read and writes for BPF_PROG_TYPE_SK_MSG. Signed-off-by: John Fastabend <john.fastabend@gmail.com> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-03-06Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
All of the conflicts were cases of overlapping changes. In net/core/devlink.c, we have to make care that the resouce size_params have become a struct member rather than a pointer to such an object. Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-26bpf: add tail call tests to test_verifierDaniel Borkmann
One of the downsides of the test_bpf module was that since being in kernel space, it couldn't test-run tail calls. Now that the test_verifier has the ability to perform run-time tests, populate the prog array so we actually jump into other BPF programs and can check all corner cases. Most useful in combination with JITs. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-02-26bpf: unify rlimit handling in selftestsDaniel Borkmann
Unify memlock handling into bpf_rlimit.h and replace all occurences in BPF kselftests with it. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-02-26Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller
Daniel Borkmann says: ==================== pull-request: bpf-next 2018-02-26 The following pull-request contains BPF updates for your *net-next* tree. The main changes are: 1) Various improvements for BPF kselftests: i) skip unprivileged tests when kernel.unprivileged_bpf_disabled sysctl knob is set, ii) count the number of skipped tests from unprivileged, iii) when a test case had an unexpected error then print the actual but also the unexpected one for better comparison, from Joe. 2) Add a sample program for collecting CPU state statistics with regards to how long the CPU resides in cstate and pstate levels. Based on cpu_idle and cpu_frequency trace points, from Leo. 3) Various x64 BPF JIT optimizations to further shrink the generated image size in order to make it more icache friendly. When tested on the Cilium generated programs, image size reduced by approx 4-5% in best case mainly due to how LLVM emits unsigned 32 bit constants, from Daniel. 4) Improvements and fixes on the BPF sockmap sample programs: i) fix the sockmap's Makefile to include nlattr.o for libbpf, ii) detach the sock ops programs from the cgroup before exit, from Prashant. 5) Avoid including xdp.h in filter.h by just forward declaring the struct xdp_rxq_info in filter.h, from Jesper. 6) Fix the BPF kselftests Makefile for cgroup_helpers.c by only declaring it a dependency for test_dev_cgroup.c but not every other test case where it is not needed, from Jesper. 7) Adjust rlimit RLIMIT_MEMLOCK for test_tcpbpf_user selftest since the default is insufficient for creating the 'global_map' used in the corresponding BPF program, from Yonghong. 8) Likewise, for the xdp_redirect sample, Tushar ran into the same when invoking xdp_redirect and xdp_monitor at the same time, therefore in order to have the sample generically work bump the limit here, too. Fix from Tushar. 9) Avoid an unnecessary NULL check in BPF_CGROUP_RUN_PROG_INET_SOCK() since sk is always guaranteed to be non-NULL, from Yafang. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
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