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>
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>
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>
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>
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>
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>
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>
Commit fbeb1603bf ("bpf: verifier: MOV64 don't mark dst reg unbounded")
revealed a typo in commit fb30d4b712 ("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: fb30d4b712 ("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>
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>
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>
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>
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: 1cf1cae963 ("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>
As commit 28e33f9d78 ("bpf: disallow arithmetic operations on
context pointer") already describes, f1174f77b5 ("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 28e33f9d78, 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: f1174f77b5 ("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>
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>
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>
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>
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>
Commit 0a67487403 ("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 1be7f75d16 ("bpf:
enable non-root eBPF programs"), we know that the running kernel
cannot support unpriv, thus continue with unpriv_disabled = true.
Fixes: 0a67487403 ("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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
Add few test cases that check the rnu-time results under JIT.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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>
I recently noticed a crash on arm64 when feeding a bogus index
into BPF tail call helper. The crash would not occur when the
interpreter is used, but only in case of JIT. Output looks as
follows:
[ 347.007486] Unable to handle kernel paging request at virtual address fffb850e96492510
[...]
[ 347.043065] [fffb850e96492510] address between user and kernel address ranges
[ 347.050205] Internal error: Oops: 96000004 [#1] SMP
[...]
[ 347.190829] x13: 0000000000000000 x12: 0000000000000000
[ 347.196128] x11: fffc047ebe782800 x10: ffff808fd7d0fd10
[ 347.201427] x9 : 0000000000000000 x8 : 0000000000000000
[ 347.206726] x7 : 0000000000000000 x6 : 001c991738000000
[ 347.212025] x5 : 0000000000000018 x4 : 000000000000ba5a
[ 347.217325] x3 : 00000000000329c4 x2 : ffff808fd7cf0500
[ 347.222625] x1 : ffff808fd7d0fc00 x0 : ffff808fd7cf0500
[ 347.227926] Process test_verifier (pid: 4548, stack limit = 0x000000007467fa61)
[ 347.235221] Call trace:
[ 347.237656] 0xffff000002f3a4fc
[ 347.240784] bpf_test_run+0x78/0xf8
[ 347.244260] bpf_prog_test_run_skb+0x148/0x230
[ 347.248694] SyS_bpf+0x77c/0x1110
[ 347.251999] el0_svc_naked+0x30/0x34
[ 347.255564] Code: 9100075a d280220a 8b0a002a d37df04b (f86b694b)
[...]
In this case the index used in BPF r3 is the same as in r1
at the time of the call, meaning we fed a pointer as index;
here, it had the value 0xffff808fd7cf0500 which sits in x2.
While I found tail calls to be working in general (also for
hitting the error cases), I noticed the following in the code
emission:
# bpftool p d j i 988
[...]
38: ldr w10, [x1,x10]
3c: cmp w2, w10
40: b.ge 0x000000000000007c <-- signed cmp
44: mov x10, #0x20 // #32
48: cmp x26, x10
4c: b.gt 0x000000000000007c
50: add x26, x26, #0x1
54: mov x10, #0x110 // #272
58: add x10, x1, x10
5c: lsl x11, x2, #3
60: ldr x11, [x10,x11] <-- faulting insn (f86b694b)
64: cbz x11, 0x000000000000007c
[...]
Meaning, the tests passed because commit ddb55992b0 ("arm64:
bpf: implement bpf_tail_call() helper") was using signed compares
instead of unsigned which as a result had the test wrongly passing.
Change this but also the tail call count test both into unsigned
and cap the index as u32. Latter we did as well in 90caccdd8c
("bpf: fix bpf_tail_call() x64 JIT") and is needed in addition here,
too. Tested on HiSilicon Hi1616.
Result after patch:
# bpftool p d j i 268
[...]
38: ldr w10, [x1,x10]
3c: add w2, w2, #0x0
40: cmp w2, w10
44: b.cs 0x0000000000000080
48: mov x10, #0x20 // #32
4c: cmp x26, x10
50: b.hi 0x0000000000000080
54: add x26, x26, #0x1
58: mov x10, #0x110 // #272
5c: add x10, x1, x10
60: lsl x11, x2, #3
64: ldr x11, [x10,x11]
68: cbz x11, 0x0000000000000080
[...]
Fixes: ddb55992b0 ("arm64: bpf: implement bpf_tail_call() helper")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The "kernel.unprivileged_bpf_disabled" sysctl, if enabled, causes all
unprivileged tests to fail because it permanently disables unprivileged
BPF access for the currently running kernel. Skip the relevant tests if
the user attempts to run the testsuite with this sysctl enabled.
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
When priviliged tests are skipped due to user rights, count the number of
skipped tests so it's more obvious that the test did not check everything.
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This makes it easier to debug off-hand when the error message isn't
exactly as expected.
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
syzkaller was able to generate the following XDP program ...
(18) r0 = 0x0
(61) r5 = *(u32 *)(r1 +12)
(04) (u32) r0 += (u32) 0
(95) exit
... and trigger a NULL pointer dereference in ___bpf_prog_run()
via bpf_prog_test_run_xdp() where this was attempted to run.
Reason is that recent xdp_rxq_info addition to XDP programs
updated all drivers, but not bpf_prog_test_run_xdp(), where
xdp_buff is set up. Thus when context rewriter does the deref
on the netdev it's NULL at runtime. Fix it by using xdp_rxq
from loopback dev. __netif_get_rx_queue() helper can also be
reused in various other locations later on.
Fixes: 02dd3291b2 ("bpf: finally expose xdp_rxq_info to XDP bpf-programs")
Reported-by: syzbot+1eb094057b338eb1fc00@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Update selftests to relfect recent changes and add various new
test cases.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Commit 111e6b4531 ("selftests/bpf: make test_verifier run most programs")
enables tools/testing/selftests/bpf/test_verifier unit cases to run
via bpf_prog_test_run command. With the latest code base,
test_verifier had one test case failure:
...
#473/p check deducing bounds from const, 2 FAIL retval 1 != 0
0: (b7) r0 = 1
1: (75) if r0 s>= 0x1 goto pc+1
R0=inv1 R1=ctx(id=0,off=0,imm=0) R10=fp0,call_-1
2: (95) exit
from 1 to 3: R0=inv1 R1=ctx(id=0,off=0,imm=0) R10=fp0,call_-1
3: (d5) if r0 s<= 0x1 goto pc+1
R0=inv1 R1=ctx(id=0,off=0,imm=0) R10=fp0,call_-1
4: (95) exit
from 3 to 5: R0=inv1 R1=ctx(id=0,off=0,imm=0) R10=fp0,call_-1
5: (1f) r1 -= r0
6: (95) exit
processed 7 insns (limit 131072), stack depth 0
...
The test case does not set return value in the test
structure and hence the return value from the prog run
is assumed to be 0. However, the actual return value is 1.
As a result, the test failed. The fix is to correctly set
the return value in the test structure.
Fixes: 111e6b4531 ("selftests/bpf: make test_verifier run most programs")
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Alexei Starovoitov says:
====================
pull-request: bpf-next 2018-01-19
The following pull-request contains BPF updates for your *net-next* tree.
The main changes are:
1) bpf array map HW offload, from Jakub.
2) support for bpf_get_next_key() for LPM map, from Yonghong.
3) test_verifier now runs loaded programs, from Alexei.
4) xdp cpumap monitoring, from Jesper.
5) variety of tests, cleanups and small x64 JIT optimization, from Daniel.
6) user space can now retrieve HW JITed program, from Jiong.
Note there is a minor conflict between Russell's arm32 JIT fixes
and removal of bpf_jit_enable variable by Daniel which should
be resolved by keeping Russell's comment and removing that variable.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
The BPF verifier conflict was some minor contextual issue.
The TUN conflict was less trivial. Cong Wang fixed a memory leak of
tfile->tx_array in 'net'. This is an skb_array. But meanwhile in
net-next tun changed tfile->tx_arry into tfile->tx_ring which is a
ptr_ring.
Signed-off-by: David S. Miller <davem@davemloft.net>
Add couple of missing test cases for eBPF div/mod by zero to the
new test_verifier prog runtime feature. Also one for an empty prog
and only exit.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
to improve test coverage make test_verifier run all successfully loaded
programs on 64-byte zero initialized data.
For clsbpf and xdp it means empty 64-byte packet.
For lwt and socket_filters it's 64-byte packet where skb->data
points after L2.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
syzkaller generated a BPF proglet and triggered a warning with
the following:
0: (b7) r0 = 0
1: (d5) if r0 s<= 0x0 goto pc+0
R0=inv0 R1=ctx(id=0,off=0,imm=0) R10=fp0
2: (1f) r0 -= r1
R0=inv0 R1=ctx(id=0,off=0,imm=0) R10=fp0
verifier internal error: known but bad sbounds
What happens is that in the first insn, r0's min/max value
are both 0 due to the immediate assignment, later in the jsle
test the bounds are updated for the min value in the false
path, meaning, they yield smin_val = 1, smax_val = 0, and when
ctx pointer is subtracted from r0, verifier bails out with the
internal error and throwing a WARN since smin_val != smax_val
for the known constant.
For min_val > max_val scenario it means that reg_set_min_max()
and reg_set_min_max_inv() (which both refine existing bounds)
demonstrated that such branch cannot be taken at runtime.
In above scenario for the case where it will be taken, the
existing [0, 0] bounds are kept intact. Meaning, the rejection
is not due to a verifier internal error, and therefore the
WARN() is not necessary either.
We could just reject such cases in adjust_{ptr,scalar}_min_max_vals()
when either known scalars have smin_val != smax_val or
umin_val != umax_val or any scalar reg with bounds
smin_val > smax_val or umin_val > umax_val. However, there
may be a small risk of breakage of buggy programs, so handle
this more gracefully and in adjust_{ptr,scalar}_min_max_vals()
just taint the dst reg as unknown scalar when we see ops with
such kind of src reg.
Reported-by: syzbot+6d362cadd45dc0a12ba4@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Alexei found that verifier does not reject stores into context
via BPF_ST instead of BPF_STX. And while looking at it, we
also should not allow XADD variant of BPF_STX.
The context rewriter is only assuming either BPF_LDX_MEM- or
BPF_STX_MEM-type operations, thus reject anything other than
that so that assumptions in the rewriter properly hold. Add
test cases as well for BPF selftests.
Fixes: d691f9e8d4 ("bpf: allow programs to write to certain skb fields")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The following snippet was throwing an 'unknown opcode cc' warning
in BPF interpreter:
0: (18) r0 = 0x0
2: (7b) *(u64 *)(r10 -16) = r0
3: (cc) (u32) r0 s>>= (u32) r0
4: (95) exit
Although a number of JITs do support BPF_ALU | BPF_ARSH | BPF_{K,X}
generation, not all of them do and interpreter does neither. We can
leave existing ones and implement it later in bpf-next for the
remaining ones, but reject this properly in verifier for the time
being.
Fixes: 17a5267067 ("bpf: verifier (add verifier core)")
Reported-by: syzbot+93c4904c5c70348a6890@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Daniel Borkmann says:
====================
pull-request: bpf-next 2017-12-28
The following pull-request contains BPF updates for your *net-next* tree.
The main changes are:
1) Fix incorrect state pruning related to recognition of zero initialized
stack slots, where stacksafe exploration would mistakenly return a
positive pruning verdict too early ignoring other slots, from Gianluca.
2) Various BPF to BPF calls related follow-up fixes. Fix an off-by-one
in maximum call depth check, and rework maximum stack depth tracking
logic to fix a bypass of the total stack size check reported by Jann.
Also fix a bug in arm64 JIT where prog->jited_len was uninitialized.
Addition of various test cases to BPF selftests, from Alexei.
3) Addition of a BPF selftest to test_verifier that is related to BPF to
BPF calls which demonstrates a late caller stack size increase and
thus out of bounds access. Fixed above in 2). Test case from Jann.
4) Addition of correlating BPF helper calls, BPF to BPF calls as well
as BPF maps to bpftool xlated dump in order to allow for better
BPF program introspection and debugging, from Daniel.
5) Fixing several bugs in BPF to BPF calls kallsyms handling in order
to get it actually to work for subprogs, from Daniel.
6) Extending sparc64 JIT support for BPF to BPF calls and fix a couple
of build errors for libbpf on sparc64, from David.
7) Allow narrower context access for BPF dev cgroup typed programs in
order to adapt to LLVM code generation. Also adjust memlock rlimit
in the test_dev_cgroup BPF selftest, from Yonghong.
8) Add netdevsim Kconfig entry to BPF selftests since test_offload.py
relies on netdevsim device being available, from Jakub.
9) Reduce scope of xdp_do_generic_redirect_map() to being static,
from Xiongwei.
10) Minor cleanups and spelling fixes in BPF verifier, from Colin.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
fix off by one error in max call depth check
and add a test
Fixes: f4d7e40a5b ("bpf: introduce function calls (verification)")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This checks that it is not possible to bypass the total stack size check in
update_stack_depth() by calling a function that uses a large amount of
stack memory *before* using a large amount of stack memory in the caller.
Currently, the first added testcase causes a rejection as expected, but
the second testcase is (AFAICS incorrectly) accepted:
[...]
#483/p calls: stack overflow using two frames (post-call access) FAIL
Unexpected success to load!
0: (85) call pc+2
caller:
R10=fp0,call_-1
callee:
frame1: R1=ctx(id=0,off=0,imm=0) R10=fp0,call_0
3: (72) *(u8 *)(r10 -300) = 0
4: (b7) r0 = 0
5: (95) exit
returning from callee:
frame1: R0_w=inv0 R1=ctx(id=0,off=0,imm=0) R10=fp0,call_0
to caller at 1:
R0_w=inv0 R10=fp0,call_-1
from 5 to 1: R0=inv0 R10=fp0,call_-1
1: (72) *(u8 *)(r10 -300) = 0
2: (95) exit
processed 6 insns, stack depth 300+300
[...]
Summary: 704 PASSED, 1 FAILED
AFAICS the JIT-generated code for the second testcase shows that this
really causes the stack pointer to be decremented by 300+300:
first function:
00000000 55 push rbp
00000001 4889E5 mov rbp,rsp
00000004 4881EC58010000 sub rsp,0x158
0000000B 4883ED28 sub rbp,byte +0x28
[...]
00000025 E89AB3AFE5 call 0xffffffffe5afb3c4
0000002A C685D4FEFFFF00 mov byte [rbp-0x12c],0x0
[...]
00000041 4883C528 add rbp,byte +0x28
00000045 C9 leave
00000046 C3 ret
second function:
00000000 55 push rbp
00000001 4889E5 mov rbp,rsp
00000004 4881EC58010000 sub rsp,0x158
0000000B 4883ED28 sub rbp,byte +0x28
[...]
00000025 C685D4FEFFFF00 mov byte [rbp-0x12c],0x0
[...]
0000003E 4883C528 add rbp,byte +0x28
00000042 C9 leave
00000043 C3 ret
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Commit cc2b14d510 ("bpf: teach verifier to recognize zero initialized
stack") introduced a very relaxed check when comparing stacks of different
states, effectively returning a positive result in many cases where it
shouldn't.
This can create problems in cases such as this following C pseudocode:
long var;
long *x = bpf_map_lookup(...);
if (!x)
return;
if (*x != 0xbeef)
var = 0;
else
var = 1;
/* This is the key part, calling a helper causes an explored state
* to be saved with the information that "var" is on the stack as
* STACK_ZERO, since the helper is first met by the verifier after
* the "var = 0" assignment. This state will however be wrongly used
* also for the "var = 1" case, so the verifier assumes "var" is always
* 0 and will replace the NULL assignment with nops, because the
* search pruning prevents it from exploring the faulty branch.
*/
bpf_ktime_get_ns();
if (var)
*(long *)0 = 0xbeef;
Fix the issue by making sure that the stack is fully explored before
returning a positive comparison result.
Also attach a couple tests that highlight the bad behavior. In the first
test, without this fix instructions 16 and 17 are replaced with nops
instead of being rejected by the verifier.
The second test, instead, allows a program to make a potentially illegal
read from the stack.
Fixes: cc2b14d510 ("bpf: teach verifier to recognize zero initialized stack")
Signed-off-by: Gianluca Borello <g.borello@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Lots of overlapping changes. Also on the net-next side
the XDP state management is handled more in the generic
layers so undo the 'net' nfp fix which isn't applicable
in net-next.
Include a necessary change by Jakub Kicinski, with log message:
====================
cls_bpf no longer takes care of offload tracking. Make sure
netdevsim performs necessary checks. This fixes a warning
caused by TC trying to remove a filter it has not added.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
