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This patch tests:
int bpf_cls(struct __sk_buff *skb)
{
/* REG_6: sk
* REG_7: tp
* REG_8: req_sk
*/
sk = skb->sk;
if (!sk)
return 0;
tp = bpf_skc_to_tcp_sock(sk);
req_sk = bpf_skc_to_tcp_request_sock(sk);
if (!req_sk)
return 0;
/* !tp has not been tested, so verifier should reject. */
return *(__u8 *)tp;
}
Signed-off-by: Martin KaFai Lau <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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The 64-bit JEQ/JNE handling in reg_set_min_max() was clearing reg->id in either
true or false branch. In the case 'if (reg->id)' check was done on the other
branch the counter part register would have reg->id == 0 when called into
find_equal_scalars(). In such case the helper would incorrectly identify other
registers with id == 0 as equivalent and propagate the state incorrectly.
Fix it by preserving ID across reg_set_min_max().
In other words any kind of comparison operator on the scalar register
should preserve its ID to recognize:
r1 = r2
if (r1 == 20) {
#1 here both r1 and r2 == 20
} else if (r2 < 20) {
#2 here both r1 and r2 < 20
}
The patch is addressing #1 case. The #2 was working correctly already.
Fixes: 75748837b7e5 ("bpf: Propagate scalar ranges through register assignments.")
Signed-off-by: Alexei Starovoitov <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Acked-by: John Fastabend <[email protected]>
Tested-by: Yonghong Song <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Add asm tests for register allocator tracking logic.
Signed-off-by: Alexei Starovoitov <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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The llvm register allocator may use two different registers representing the
same virtual register. In such case the following pattern can be observed:
1047: (bf) r9 = r6
1048: (a5) if r6 < 0x1000 goto pc+1
1050: ...
1051: (a5) if r9 < 0x2 goto pc+66
1052: ...
1053: (bf) r2 = r9 /* r2 needs to have upper and lower bounds */
This is normal behavior of greedy register allocator.
The slides 137+ explain why regalloc introduces such register copy:
http://llvm.org/devmtg/2018-04/slides/Yatsina-LLVM%20Greedy%20Register%20Allocator.pdf
There is no way to tell llvm 'not to do this'.
Hence the verifier has to recognize such patterns.
In order to track this information without backtracking allocate ID
for scalars in a similar way as it's done for find_good_pkt_pointers().
When the verifier encounters r9 = r6 assignment it will assign the same ID
to both registers. Later if either register range is narrowed via conditional
jump propagate the register state into the other register.
Clear register ID in adjust_reg_min_max_vals() for any alu instruction. The
register ID is ignored for scalars in regsafe() and doesn't affect state
pruning. mark_reg_unknown() clears the ID. It's used to process call, endian
and other instructions. Hence ID is explicitly cleared only in
adjust_reg_min_max_vals() and in 32-bit mov.
Signed-off-by: Alexei Starovoitov <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Acked-by: John Fastabend <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Commit 4976b718c355 ("bpf: Introduce pseudo_btf_id") switched
the order of check_subprogs() and resolve_pseudo_ldimm() in
the verifier. Now an empty prog expects to see the error "last
insn is not an the prog of a single invalid ldimm exit or jmp"
instead, because the check for subprogs comes first. It's now
pointless to validate that half of ldimm64 won't be the last
instruction.
Tested:
# ./test_verifier
Summary: 1129 PASSED, 537 SKIPPED, 0 FAILED
and the full set of bpf selftests.
Fixes: 4976b718c355 ("bpf: Introduce pseudo_btf_id")
Signed-off-by: Hao Luo <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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If we AND two values together that are known in the 32bit subregs, but not
known in the 64bit registers we rely on the tnum value to report the 32bit
subreg is known. And do not use mark_reg_known() directly from
scalar32_min_max_and()
Add an AND test to cover the case with known 32bit subreg, but unknown
64bit reg.
Signed-off-by: John Fastabend <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
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The patch tests for:
1. bpf_sk_release() can be called on a tcp_sock btf_id ptr.
2. Ensure the tcp_sock btf_id pointer cannot be used
after bpf_sk_release().
Signed-off-by: Martin KaFai Lau <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Acked-by: Lorenz Bauer <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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LD_[ABS|IND] instructions may return from the function early. bpf_tail_call
pseudo instruction is either fallthrough or return. Allow them in the
subprograms only when subprograms are BTF annotated and have scalar return
types. Allow ld_abs and tail_call in the main program even if it calls into
subprograms. In the past that was not ok to do for ld_abs, since it was JITed
with special exit sequence. Since bpf_gen_ld_abs() was introduced the ld_abs
looks like normal exit insn from JIT point of view, so it's safe to allow them
in the main program.
Signed-off-by: Alexei Starovoitov <[email protected]>
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Change selftest map_ptr_kern.c with disabling inlining for
one of subtests, which will fail the test without previous
verifier change. Also added to verifier test for both
"map_ptr += scalar" and "scalar += map_ptr" arithmetic.
Signed-off-by: Yonghong Song <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Added some test_verifier bounds check test cases for
xor operations.
$ ./test_verifier
...
#78/u bounds check for reg = 0, reg xor 1 OK
#78/p bounds check for reg = 0, reg xor 1 OK
#79/u bounds check for reg32 = 0, reg32 xor 1 OK
#79/p bounds check for reg32 = 0, reg32 xor 1 OK
#80/u bounds check for reg = 2, reg xor 3 OK
#80/p bounds check for reg = 2, reg xor 3 OK
#81/u bounds check for reg = any, reg xor 3 OK
#81/p bounds check for reg = any, reg xor 3 OK
#82/u bounds check for reg32 = any, reg32 xor 3 OK
#82/p bounds check for reg32 = any, reg32 xor 3 OK
#83/u bounds check for reg > 0, reg xor 3 OK
#83/p bounds check for reg > 0, reg xor 3 OK
#84/u bounds check for reg32 > 0, reg32 xor 3 OK
#84/p bounds check for reg32 > 0, reg32 xor 3 OK
...
Signed-off-by: Yonghong Song <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Cc: John Fastabend <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Adding verifier test for attaching tracing program and
calling d_path helper from within and testing that it's
allowed for dentry_open function and denied for 'd_path'
function with appropriate error.
Signed-off-by: Jiri Olsa <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Resolved kernel/bpf/btf.c using instructions from merge commit
69138b34a7248d2396ab85c8652e20c0c39beaba
Signed-off-by: David S. Miller <[email protected]>
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Exercise verifier access checks for bpf_sk_lookup context fields.
Signed-off-by: Jakub Sitnicki <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Since the BPF_PROG_TYPE_CGROUP_SOCKOPT verifier test does not set an
attach type, bpf_prog_load_check_attach() disallows loading the program
and the test is always skipped:
#434/p perfevent for cgroup sockopt SKIP (unsupported program type 25)
Fix the issue by setting a valid attach type.
Fixes: 0456ea170cd6 ("bpf: Enable more helpers for BPF_PROG_TYPE_CGROUP_{DEVICE,SYSCTL,SOCKOPT}")
Signed-off-by: Jean-Philippe Brucker <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Reviewed-by: Jakub Sitnicki <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Add selftests to test access to map pointers from bpf program for all
map types except struct_ops (that one would need additional work).
verifier test focuses mostly on scenarios that must be rejected.
prog_tests test focuses on accessing multiple fields both scalar and a
nested struct from bpf program and verifies that those fields have
expected values.
Signed-off-by: Andrey Ignatov <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Acked-by: John Fastabend <[email protected]>
Acked-by: Martin KaFai Lau <[email protected]>
Link: https://lore.kernel.org/bpf/139a6a17f8016491e39347849b951525335c6eb4.1592600985.git.rdna@fb.com
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There are multiple use-cases when it's convenient to have access to bpf
map fields, both `struct bpf_map` and map type specific struct-s such as
`struct bpf_array`, `struct bpf_htab`, etc.
For example while working with sock arrays it can be necessary to
calculate the key based on map->max_entries (some_hash % max_entries).
Currently this is solved by communicating max_entries via "out-of-band"
channel, e.g. via additional map with known key to get info about target
map. That works, but is not very convenient and error-prone while
working with many maps.
In other cases necessary data is dynamic (i.e. unknown at loading time)
and it's impossible to get it at all. For example while working with a
hash table it can be convenient to know how much capacity is already
used (bpf_htab.count.counter for BPF_F_NO_PREALLOC case).
At the same time kernel knows this info and can provide it to bpf
program.
Fill this gap by adding support to access bpf map fields from bpf
program for both `struct bpf_map` and map type specific fields.
Support is implemented via btf_struct_access() so that a user can define
their own `struct bpf_map` or map type specific struct in their program
with only necessary fields and preserve_access_index attribute, cast a
map to this struct and use a field.
For example:
struct bpf_map {
__u32 max_entries;
} __attribute__((preserve_access_index));
struct bpf_array {
struct bpf_map map;
__u32 elem_size;
} __attribute__((preserve_access_index));
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 4);
__type(key, __u32);
__type(value, __u32);
} m_array SEC(".maps");
SEC("cgroup_skb/egress")
int cg_skb(void *ctx)
{
struct bpf_array *array = (struct bpf_array *)&m_array;
struct bpf_map *map = (struct bpf_map *)&m_array;
/* .. use map->max_entries or array->map.max_entries .. */
}
Similarly to other btf_struct_access() use-cases (e.g. struct tcp_sock
in net/ipv4/bpf_tcp_ca.c) the patch allows access to any fields of
corresponding struct. Only reading from map fields is supported.
For btf_struct_access() to work there should be a way to know btf id of
a struct that corresponds to a map type. To get btf id there should be a
way to get a stringified name of map-specific struct, such as
"bpf_array", "bpf_htab", etc for a map type. Two new fields are added to
`struct bpf_map_ops` to handle it:
* .map_btf_name keeps a btf name of a struct returned by map_alloc();
* .map_btf_id is used to cache btf id of that struct.
To make btf ids calculation cheaper they're calculated once while
preparing btf_vmlinux and cached same way as it's done for btf_id field
of `struct bpf_func_proto`
While calculating btf ids, struct names are NOT checked for collision.
Collisions will be checked as a part of the work to prepare btf ids used
in verifier in compile time that should land soon. The only known
collision for `struct bpf_htab` (kernel/bpf/hashtab.c vs
net/core/sock_map.c) was fixed earlier.
Both new fields .map_btf_name and .map_btf_id must be set for a map type
for the feature to work. If neither is set for a map type, verifier will
return ENOTSUPP on a try to access map_ptr of corresponding type. If
just one of them set, it's verifier misconfiguration.
Only `struct bpf_array` for BPF_MAP_TYPE_ARRAY and `struct bpf_htab` for
BPF_MAP_TYPE_HASH are supported by this patch. Other map types will be
supported separately.
The feature is available only for CONFIG_DEBUG_INFO_BTF=y and gated by
perfmon_capable() so that unpriv programs won't have access to bpf map
fields.
Signed-off-by: Andrey Ignatov <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Acked-by: John Fastabend <[email protected]>
Acked-by: Martin KaFai Lau <[email protected]>
Link: https://lore.kernel.org/bpf/6479686a0cd1e9067993df57b4c3eef0e276fec9.1592600985.git.rdna@fb.com
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Added two test_verifier subtests for 32bit pointer/scalar arithmetic
with BPF_SUB operator. They are passing verifier now.
Signed-off-by: Yonghong Song <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Since commit 0ebeea8ca8a4 ("bpf: Restrict bpf_probe_read{, str}() only to
archs where they work") 44 verifier tests fail on s390 due to not having
bpf_probe_read anymore. Fix by using bpf_probe_read_kernel.
Signed-off-by: Ilya Leoshkevich <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Adjust verifier test due to addition of new field.
Fixes: c3c16f2ea6d2 ("bpf: Add rx_queue_mapping to bpf_sock")
Signed-off-by: Alexei Starovoitov <[email protected]>
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This commit adds a new MPSC ring buffer implementation into BPF ecosystem,
which allows multiple CPUs to submit data to a single shared ring buffer. On
the consumption side, only single consumer is assumed.
Motivation
----------
There are two distinctive motivators for this work, which are not satisfied by
existing perf buffer, which prompted creation of a new ring buffer
implementation.
- more efficient memory utilization by sharing ring buffer across CPUs;
- preserving ordering of events that happen sequentially in time, even
across multiple CPUs (e.g., fork/exec/exit events for a task).
These two problems are independent, but perf buffer fails to satisfy both.
Both are a result of a choice to have per-CPU perf ring buffer. Both can be
also solved by having an MPSC implementation of ring buffer. The ordering
problem could technically be solved for perf buffer with some in-kernel
counting, but given the first one requires an MPSC buffer, the same solution
would solve the second problem automatically.
Semantics and APIs
------------------
Single ring buffer is presented to BPF programs as an instance of BPF map of
type BPF_MAP_TYPE_RINGBUF. Two other alternatives considered, but ultimately
rejected.
One way would be to, similar to BPF_MAP_TYPE_PERF_EVENT_ARRAY, make
BPF_MAP_TYPE_RINGBUF could represent an array of ring buffers, but not enforce
"same CPU only" rule. This would be more familiar interface compatible with
existing perf buffer use in BPF, but would fail if application needed more
advanced logic to lookup ring buffer by arbitrary key. HASH_OF_MAPS addresses
this with current approach. Additionally, given the performance of BPF
ringbuf, many use cases would just opt into a simple single ring buffer shared
among all CPUs, for which current approach would be an overkill.
Another approach could introduce a new concept, alongside BPF map, to
represent generic "container" object, which doesn't necessarily have key/value
interface with lookup/update/delete operations. This approach would add a lot
of extra infrastructure that has to be built for observability and verifier
support. It would also add another concept that BPF developers would have to
familiarize themselves with, new syntax in libbpf, etc. But then would really
provide no additional benefits over the approach of using a map.
BPF_MAP_TYPE_RINGBUF doesn't support lookup/update/delete operations, but so
doesn't few other map types (e.g., queue and stack; array doesn't support
delete, etc).
The approach chosen has an advantage of re-using existing BPF map
infrastructure (introspection APIs in kernel, libbpf support, etc), being
familiar concept (no need to teach users a new type of object in BPF program),
and utilizing existing tooling (bpftool). For common scenario of using
a single ring buffer for all CPUs, it's as simple and straightforward, as
would be with a dedicated "container" object. On the other hand, by being
a map, it can be combined with ARRAY_OF_MAPS and HASH_OF_MAPS map-in-maps to
implement a wide variety of topologies, from one ring buffer for each CPU
(e.g., as a replacement for perf buffer use cases), to a complicated
application hashing/sharding of ring buffers (e.g., having a small pool of
ring buffers with hashed task's tgid being a look up key to preserve order,
but reduce contention).
Key and value sizes are enforced to be zero. max_entries is used to specify
the size of ring buffer and has to be a power of 2 value.
There are a bunch of similarities between perf buffer
(BPF_MAP_TYPE_PERF_EVENT_ARRAY) and new BPF ring buffer semantics:
- variable-length records;
- if there is no more space left in ring buffer, reservation fails, no
blocking;
- memory-mappable data area for user-space applications for ease of
consumption and high performance;
- epoll notifications for new incoming data;
- but still the ability to do busy polling for new data to achieve the
lowest latency, if necessary.
BPF ringbuf provides two sets of APIs to BPF programs:
- bpf_ringbuf_output() allows to *copy* data from one place to a ring
buffer, similarly to bpf_perf_event_output();
- bpf_ringbuf_reserve()/bpf_ringbuf_commit()/bpf_ringbuf_discard() APIs
split the whole process into two steps. First, a fixed amount of space is
reserved. If successful, a pointer to a data inside ring buffer data area
is returned, which BPF programs can use similarly to a data inside
array/hash maps. Once ready, this piece of memory is either committed or
discarded. Discard is similar to commit, but makes consumer ignore the
record.
bpf_ringbuf_output() has disadvantage of incurring extra memory copy, because
record has to be prepared in some other place first. But it allows to submit
records of the length that's not known to verifier beforehand. It also closely
matches bpf_perf_event_output(), so will simplify migration significantly.
bpf_ringbuf_reserve() avoids the extra copy of memory by providing a memory
pointer directly to ring buffer memory. In a lot of cases records are larger
than BPF stack space allows, so many programs have use extra per-CPU array as
a temporary heap for preparing sample. bpf_ringbuf_reserve() avoid this needs
completely. But in exchange, it only allows a known constant size of memory to
be reserved, such that verifier can verify that BPF program can't access
memory outside its reserved record space. bpf_ringbuf_output(), while slightly
slower due to extra memory copy, covers some use cases that are not suitable
for bpf_ringbuf_reserve().
The difference between commit and discard is very small. Discard just marks
a record as discarded, and such records are supposed to be ignored by consumer
code. Discard is useful for some advanced use-cases, such as ensuring
all-or-nothing multi-record submission, or emulating temporary malloc()/free()
within single BPF program invocation.
Each reserved record is tracked by verifier through existing
reference-tracking logic, similar to socket ref-tracking. It is thus
impossible to reserve a record, but forget to submit (or discard) it.
bpf_ringbuf_query() helper allows to query various properties of ring buffer.
Currently 4 are supported:
- BPF_RB_AVAIL_DATA returns amount of unconsumed data in ring buffer;
- BPF_RB_RING_SIZE returns the size of ring buffer;
- BPF_RB_CONS_POS/BPF_RB_PROD_POS returns current logical possition of
consumer/producer, respectively.
Returned values are momentarily snapshots of ring buffer state and could be
off by the time helper returns, so this should be used only for
debugging/reporting reasons or for implementing various heuristics, that take
into account highly-changeable nature of some of those characteristics.
One such heuristic might involve more fine-grained control over poll/epoll
notifications about new data availability in ring buffer. Together with
BPF_RB_NO_WAKEUP/BPF_RB_FORCE_WAKEUP flags for output/commit/discard helpers,
it allows BPF program a high degree of control and, e.g., more efficient
batched notifications. Default self-balancing strategy, though, should be
adequate for most applications and will work reliable and efficiently already.
Design and implementation
-------------------------
This reserve/commit schema allows a natural way for multiple producers, either
on different CPUs or even on the same CPU/in the same BPF program, to reserve
independent records and work with them without blocking other producers. This
means that if BPF program was interruped by another BPF program sharing the
same ring buffer, they will both get a record reserved (provided there is
enough space left) and can work with it and submit it independently. This
applies to NMI context as well, except that due to using a spinlock during
reservation, in NMI context, bpf_ringbuf_reserve() might fail to get a lock,
in which case reservation will fail even if ring buffer is not full.
The ring buffer itself internally is implemented as a power-of-2 sized
circular buffer, with two logical and ever-increasing counters (which might
wrap around on 32-bit architectures, that's not a problem):
- consumer counter shows up to which logical position consumer consumed the
data;
- producer counter denotes amount of data reserved by all producers.
Each time a record is reserved, producer that "owns" the record will
successfully advance producer counter. At that point, data is still not yet
ready to be consumed, though. Each record has 8 byte header, which contains
the length of reserved record, as well as two extra bits: busy bit to denote
that record is still being worked on, and discard bit, which might be set at
commit time if record is discarded. In the latter case, consumer is supposed
to skip the record and move on to the next one. Record header also encodes
record's relative offset from the beginning of ring buffer data area (in
pages). This allows bpf_ringbuf_commit()/bpf_ringbuf_discard() to accept only
the pointer to the record itself, without requiring also the pointer to ring
buffer itself. Ring buffer memory location will be restored from record
metadata header. This significantly simplifies verifier, as well as improving
API usability.
Producer counter increments are serialized under spinlock, so there is
a strict ordering between reservations. Commits, on the other hand, are
completely lockless and independent. All records become available to consumer
in the order of reservations, but only after all previous records where
already committed. It is thus possible for slow producers to temporarily hold
off submitted records, that were reserved later.
Reservation/commit/consumer protocol is verified by litmus tests in
Documentation/litmus-test/bpf-rb.
One interesting implementation bit, that significantly simplifies (and thus
speeds up as well) implementation of both producers and consumers is how data
area is mapped twice contiguously back-to-back in the virtual memory. This
allows to not take any special measures for samples that have to wrap around
at the end of the circular buffer data area, because the next page after the
last data page would be first data page again, and thus the sample will still
appear completely contiguous in virtual memory. See comment and a simple ASCII
diagram showing this visually in bpf_ringbuf_area_alloc().
Another feature that distinguishes BPF ringbuf from perf ring buffer is
a self-pacing notifications of new data being availability.
bpf_ringbuf_commit() implementation will send a notification of new record
being available after commit only if consumer has already caught up right up
to the record being committed. If not, consumer still has to catch up and thus
will see new data anyways without needing an extra poll notification.
Benchmarks (see tools/testing/selftests/bpf/benchs/bench_ringbuf.c) show that
this allows to achieve a very high throughput without having to resort to
tricks like "notify only every Nth sample", which are necessary with perf
buffer. For extreme cases, when BPF program wants more manual control of
notifications, commit/discard/output helpers accept BPF_RB_NO_WAKEUP and
BPF_RB_FORCE_WAKEUP flags, which give full control over notifications of data
availability, but require extra caution and diligence in using this API.
Comparison to alternatives
--------------------------
Before considering implementing BPF ring buffer from scratch existing
alternatives in kernel were evaluated, but didn't seem to meet the needs. They
largely fell into few categores:
- per-CPU buffers (perf, ftrace, etc), which don't satisfy two motivations
outlined above (ordering and memory consumption);
- linked list-based implementations; while some were multi-producer designs,
consuming these from user-space would be very complicated and most
probably not performant; memory-mapping contiguous piece of memory is
simpler and more performant for user-space consumers;
- io_uring is SPSC, but also requires fixed-sized elements. Naively turning
SPSC queue into MPSC w/ lock would have subpar performance compared to
locked reserve + lockless commit, as with BPF ring buffer. Fixed sized
elements would be too limiting for BPF programs, given existing BPF
programs heavily rely on variable-sized perf buffer already;
- specialized implementations (like a new printk ring buffer, [0]) with lots
of printk-specific limitations and implications, that didn't seem to fit
well for intended use with BPF programs.
[0] https://lwn.net/Articles/779550/
Signed-off-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>
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xdp_umem.c had overlapping changes between the 64-bit math fix
for the calculation of npgs and the removal of the zerocopy
memory type which got rid of the chunk_size_nohdr member.
The mlx5 Kconfig conflict is a case where we just take the
net-next copy of the Kconfig entry dependency as it takes on
the ESWITCH dependency by one level of indirection which is
what the 'net' conflicting change is trying to ensure.
Signed-off-by: David S. Miller <[email protected]>
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Added a verifier test for assigning 32bit reg states to
64bit where 32bit reg holds a constant value of 0.
Without previous kernel verifier.c fix, the test in
this patch will fail.
Signed-off-by: Yonghong Song <[email protected]>
Signed-off-by: John Fastabend <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/159077335867.6014.2075350327073125374.stgit@john-Precision-5820-Tower
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After previous fix for zero extension test_verifier tests #65 and #66 now
fail. Before the fix we can see the alu32 mov op at insn 10
10: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0)
R1_w=invP(id=0,
smin_value=4294967168,smax_value=4294967423,
umin_value=4294967168,umax_value=4294967423,
var_off=(0x0; 0x1ffffffff),
s32_min_value=-2147483648,s32_max_value=2147483647,
u32_min_value=0,u32_max_value=-1)
R10=fp0 fp-8_w=mmmmmmmm
10: (bc) w1 = w1
11: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0)
R1_w=invP(id=0,
smin_value=0,smax_value=2147483647,
umin_value=0,umax_value=4294967295,
var_off=(0x0; 0xffffffff),
s32_min_value=-2147483648,s32_max_value=2147483647,
u32_min_value=0,u32_max_value=-1)
R10=fp0 fp-8_w=mmmmmmmm
After the fix at insn 10 because we have 's32_min_value < 0' the following
step 11 now has 'smax_value=U32_MAX' where before we pulled the s32_max_value
bound into the smax_value as seen above in 11 with smax_value=2147483647.
10: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0)
R1_w=inv(id=0,
smin_value=4294967168,smax_value=4294967423,
umin_value=4294967168,umax_value=4294967423,
var_off=(0x0; 0x1ffffffff),
s32_min_value=-2147483648, s32_max_value=2147483647,
u32_min_value=0,u32_max_value=-1)
R10=fp0 fp-8_w=mmmmmmmm
10: (bc) w1 = w1
11: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0)
R1_w=inv(id=0,
smin_value=0,smax_value=4294967295,
umin_value=0,umax_value=4294967295,
var_off=(0x0; 0xffffffff),
s32_min_value=-2147483648, s32_max_value=2147483647,
u32_min_value=0, u32_max_value=-1)
R10=fp0 fp-8_w=mmmmmmmm
The fall out of this is by the time we get to the failing instruction at
step 14 where previously we had the following:
14: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0)
R1_w=inv(id=0,
smin_value=72057594021150720,smax_value=72057594029539328,
umin_value=72057594021150720,umax_value=72057594029539328,
var_off=(0xffffffff000000; 0xffffff),
s32_min_value=-16777216,s32_max_value=-1,
u32_min_value=-16777216,u32_max_value=-1)
R10=fp0 fp-8_w=mmmmmmmm
14: (0f) r0 += r1
We now have,
14: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0)
R1_w=inv(id=0,
smin_value=0,smax_value=72057594037927935,
umin_value=0,umax_value=72057594037927935,
var_off=(0x0; 0xffffffffffffff),
s32_min_value=-2147483648,s32_max_value=2147483647,
u32_min_value=0,u32_max_value=-1)
R10=fp0 fp-8_w=mmmmmmmm
14: (0f) r0 += r1
In the original step 14 'smin_value=72057594021150720' this trips the logic
in the verifier function check_reg_sane_offset(),
if (smin >= BPF_MAX_VAR_OFF || smin <= -BPF_MAX_VAR_OFF) {
verbose(env, "value %lld makes %s pointer be out of bounds\n",
smin, reg_type_str[type]);
return false;
}
Specifically, the 'smin <= -BPF_MAX_VAR_OFF' check. But with the fix
at step 14 we have bounds 'smin_value=0' so the above check is not tripped
because BPF_MAX_VAR_OFF=1<<29.
We have a smin_value=0 here because at step 10 the smaller smin_value=0 means
the subtractions at steps 11 and 12 bring the smin_value negative.
11: (17) r1 -= 2147483584
12: (17) r1 -= 2147483584
13: (77) r1 >>= 8
Then the shift clears the top bit and smin_value is set to 0. Note we still
have the smax_value in the fixed code so any reads will fail. An alternative
would be to have reg_sane_check() do both smin and smax value tests.
To fix the test we can omit the 'r1 >>=8' at line 13. This will change the
err string, but keeps the intention of the test as suggseted by the title,
"check after truncation of boundary-crossing range". If the verifier logic
changes a different value is likely to be thrown in the error or the error
will no longer be thrown forcing this test to be examined. With this change
we see the new state at step 13.
13: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0)
R1_w=invP(id=0,
smin_value=-4294967168,smax_value=127,
umin_value=0,umax_value=18446744073709551615,
s32_min_value=-2147483648,s32_max_value=2147483647,
u32_min_value=0,u32_max_value=-1)
R10=fp0 fp-8_w=mmmmmmmm
Giving the expected out of bounds error, "value -4294967168 makes map_value
pointer be out of bounds" However, for unpriv case we see a different error
now because of the mixed signed bounds pointer arithmatic. This seems OK so
I've only added the unpriv_errstr for this. Another optino may have been to
do addition on r1 instead of subtraction but I favor the approach above
slightly.
Signed-off-by: John Fastabend <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Acked-by: Yonghong Song <[email protected]>
Link: https://lore.kernel.org/bpf/159077333942.6014.14004320043595756079.stgit@john-Precision-5820-Tower
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When we have pointer type that is known to be non-null we only follow
the non-null branch. This adds tests to cover the map_value pointer
returned from a map lookup. To force an error if both branches are
followed we do an ALU op on R10.
Signed-off-by: John Fastabend <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/159009168650.6313.7434084136067263554.stgit@john-Precision-5820-Tower
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When we have pointer type that is known to be non-null and comparing
against zero we only follow the non-null branch. This adds tests to
cover this case for reference tracking. Also add the other case when
comparison against a non-zero value and ensure we still fail with
unreleased reference.
Signed-off-by: John Fastabend <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/159009166599.6313.1593680633787453767.stgit@john-Precision-5820-Tower
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Make all test_verifier test exercise CAP_BPF and CAP_PERFMON
Signed-off-by: Alexei Starovoitov <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Check that verifier allows passing a map of type:
BPF_MAP_TYPE_REUSEPORT_SOCKARRARY, or
BPF_MAP_TYPE_SOCKMAP, or
BPF_MAP_TYPE_SOCKHASH
... to bpf_sk_select_reuseport helper.
Suggested-by: John Fastabend <[email protected]>
Signed-off-by: Jakub Sitnicki <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Now that bpf_map_lookup_elem() is white-listed for SOCKMAP/SOCKHASH,
replace the tests which check that verifier prevents lookup on these map
types with ones that ensure that lookup operation is permitted, but only
with a release of acquired socket reference.
Signed-off-by: Jakub Sitnicki <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Acked-by: John Fastabend <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Currently the following prog types don't fall back to bpf_base_func_proto()
(instead they have cgroup_base_func_proto which has a limited set of
helpers from bpf_base_func_proto):
* BPF_PROG_TYPE_CGROUP_DEVICE
* BPF_PROG_TYPE_CGROUP_SYSCTL
* BPF_PROG_TYPE_CGROUP_SOCKOPT
I don't see any specific reason why we shouldn't use bpf_base_func_proto(),
every other type of program (except bpf-lirc and, understandably, tracing)
use it, so let's fall back to bpf_base_func_proto for those prog types
as well.
This basically boils down to adding access to the following helpers:
* BPF_FUNC_get_prandom_u32
* BPF_FUNC_get_smp_processor_id
* BPF_FUNC_get_numa_node_id
* BPF_FUNC_tail_call
* BPF_FUNC_ktime_get_ns
* BPF_FUNC_spin_lock (CAP_SYS_ADMIN)
* BPF_FUNC_spin_unlock (CAP_SYS_ADMIN)
* BPF_FUNC_jiffies64 (CAP_SYS_ADMIN)
I've also added bpf_perf_event_output() because it's really handy for
logging and debugging.
Signed-off-by: Stanislav Fomichev <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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This patch adds a test to test_verifier that writes the lower 8 bits of
R10 (aka FP) using BPF_B to an array map and reads the result back. The
expected behavior is that the result should be the same as first copying
R10 to R9, and then storing / loading the lower 8 bits of R9.
This test catches a bug that was present in the x86-64 JIT that caused
an incorrect encoding for BPF_STX BPF_B when the source operand is R10.
Signed-off-by: Xi Wang <[email protected]>
Signed-off-by: Luke Nelson <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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When check_xadd() verifies an XADD operation on a pointer to a stack slot
containing a spilled pointer, check_stack_read() verifies that the read,
which is part of XADD, is valid. However, since the placeholder value -1 is
passed as `value_regno`, check_stack_read() can only return a binary
decision and can't return the type of the value that was read. The intent
here is to verify whether the value read from the stack slot may be used as
a SCALAR_VALUE; but since check_stack_read() doesn't check the type, and
the type information is lost when check_stack_read() returns, this is not
enforced, and a malicious user can abuse XADD to leak spilled kernel
pointers.
Fix it by letting check_stack_read() verify that the value is usable as a
SCALAR_VALUE if no type information is passed to the caller.
To be able to use __is_pointer_value() in check_stack_read(), move it up.
Fix up the expected unprivileged error message for a BPF selftest that,
until now, assumed that unprivileged users can use XADD on stack-spilled
pointers. This also gives us a test for the behavior introduced in this
patch for free.
In theory, this could also be fixed by forbidding XADD on stack spills
entirely, since XADD is a locked operation (for operations on memory with
concurrency) and there can't be any concurrency on the BPF stack; but
Alexei has said that he wants to keep XADD on stack slots working to avoid
changes to the test suite [1].
The following BPF program demonstrates how to leak a BPF map pointer as an
unprivileged user using this bug:
// r7 = map_pointer
BPF_LD_MAP_FD(BPF_REG_7, small_map),
// r8 = launder(map_pointer)
BPF_STX_MEM(BPF_DW, BPF_REG_FP, BPF_REG_7, -8),
BPF_MOV64_IMM(BPF_REG_1, 0),
((struct bpf_insn) {
.code = BPF_STX | BPF_DW | BPF_XADD,
.dst_reg = BPF_REG_FP,
.src_reg = BPF_REG_1,
.off = -8
}),
BPF_LDX_MEM(BPF_DW, BPF_REG_8, BPF_REG_FP, -8),
// store r8 into map
BPF_MOV64_REG(BPF_REG_ARG1, BPF_REG_7),
BPF_MOV64_REG(BPF_REG_ARG2, BPF_REG_FP),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_ARG2, -4),
BPF_ST_MEM(BPF_W, BPF_REG_ARG2, 0, 0),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_EXIT_INSN(),
BPF_STX_MEM(BPF_DW, BPF_REG_0, BPF_REG_8, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN()
[1] https://lore.kernel.org/bpf/[email protected]/
Fixes: 17a5267067f3 ("bpf: verifier (add verifier core)")
Signed-off-by: Jann Horn <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Daniel Borkmann says:
====================
pull-request: bpf 2020-04-10
The following pull-request contains BPF updates for your *net* tree.
We've added 13 non-merge commits during the last 7 day(s) which contain
a total of 13 files changed, 137 insertions(+), 43 deletions(-).
The main changes are:
1) JIT code emission fixes for riscv and arm32, from Luke Nelson and Xi Wang.
2) Disable vmlinux BTF info if GCC_PLUGIN_RANDSTRUCT is used, from Slava Bacherikov.
3) Fix oob write in AF_XDP when meta data is used, from Li RongQing.
4) Fix bpf_get_link_xdp_id() handling on single prog when flags are specified,
from Andrey Ignatov.
5) Fix sk_assign() BPF helper for request sockets that can have sk_reuseport
field uninitialized, from Joe Stringer.
6) Fix mprotect() test case for the BPF LSM, from KP Singh.
====================
Signed-off-by: David S. Miller <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx
Pull SPDX updates from Greg KH:
"Here are three SPDX patches for 5.7-rc1.
One fixes up the SPDX tag for a single driver, while the other two go
through the tree and add SPDX tags for all of the .gitignore files as
needed.
Nothing too complex, but you will get a merge conflict with your
current tree, that should be trivial to handle (one file modified by
two things, one file deleted.)
All three of these have been in linux-next for a while, with no
reported issues other than the merge conflict"
* tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx:
ASoC: MT6660: make spdxcheck.py happy
.gitignore: add SPDX License Identifier
.gitignore: remove too obvious comments
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There are a couple of spelling mistakes in two literal strings, fix them.
Signed-off-by: Colin Ian King <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Signed-off-by: David S. Miller <[email protected]>
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Its possible to have divergent ALU32 and ALU64 bounds when using JMP32
instructins and ALU64 arithmatic operations. Sometimes the clang will
even generate this code. Because the case is a bit tricky lets add
a specific test for it.
Here is pseudocode asm version to illustrate the idea,
1 r0 = 0xffffffff00000001;
2 if w0 > 1 goto %l[fail];
3 r0 += 1
5 if w0 > 2 goto %l[fail]
6 exit
The intent here is the verifier will fail the load if the 32bit bounds
are not tracked correctly through ALU64 op. Similarly we can check the
64bit bounds are correctly zero extended after ALU32 ops.
1 r0 = 0xffffffff00000001;
2 w0 += 1
2 if r0 > 3 goto %l[fail];
6 exit
The above will fail if we do not correctly zero extend 64bit bounds
after 32bit op.
Signed-off-by: John Fastabend <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/158560430155.10843.514209255758200922.stgit@john-Precision-5820-Tower
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After changes to add update_reg_bounds after ALU ops and 32-bit bounds
tracking truncation of boundary crossing range will fail earlier and with
a different error message. Now the test error trace is the following
11: (17) r1 -= 2147483584
12: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0)
R1_w=invP(id=0,smin_value=-2147483584,smax_value=63)
R10=fp0 fp-8_w=mmmmmmmm
12: (17) r1 -= 2147483584
13: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0)
R1_w=invP(id=0,
umin_value=18446744069414584448,umax_value=18446744071562068095,
var_off=(0xffffffff00000000; 0xffffffff))
R10=fp0 fp-8_w=mmmmmmmm
13: (77) r1 >>= 8
14: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0)
R1_w=invP(id=0,
umin_value=72057594021150720,umax_value=72057594029539328,
var_off=(0xffffffff000000; 0xffffff),
s32_min_value=-16777216,s32_max_value=-1,
u32_min_value=-16777216)
R10=fp0 fp-8_w=mmmmmmmm
14: (0f) r0 += r1
value 72057594021150720 makes map_value pointer be out of bounds
Because we have 'umin_value == umax_value' instead of previously
where 'umin_value != umax_value' we can now fail earlier noting
that pointer addition is out of bounds.
Signed-off-by: John Fastabend <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/158560428103.10843.6316594510312781186.stgit@john-Precision-5820-Tower
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With current ALU32 subreg handling and retval refine fix from last
patches we see an expected failure in test_verifier. With verbose
verifier state being printed at each step for clarity we have the
following relavent lines [I omit register states that are not
necessarily useful to see failure cause],
#101/p bpf_get_stack return R0 within range FAIL
Failed to load prog 'Success'!
[..]
14: (85) call bpf_get_stack#67
R0_w=map_value(id=0,off=0,ks=8,vs=48,imm=0)
R3_w=inv48
15:
R0=inv(id=0,smax_value=48,var32_off=(0x0; 0xffffffff))
15: (b7) r1 = 0
16:
R0=inv(id=0,smax_value=48,var32_off=(0x0; 0xffffffff))
R1_w=inv0
16: (bf) r8 = r0
17:
R0=inv(id=0,smax_value=48,var32_off=(0x0; 0xffffffff))
R1_w=inv0
R8_w=inv(id=0,smax_value=48,var32_off=(0x0; 0xffffffff))
17: (67) r8 <<= 32
18:
R0=inv(id=0,smax_value=48,var32_off=(0x0; 0xffffffff))
R1_w=inv0
R8_w=inv(id=0,smax_value=9223372032559808512,
umax_value=18446744069414584320,
var_off=(0x0; 0xffffffff00000000),
s32_min_value=0,
s32_max_value=0,
u32_max_value=0,
var32_off=(0x0; 0x0))
18: (c7) r8 s>>= 32
19
R0=inv(id=0,smax_value=48,var32_off=(0x0; 0xffffffff))
R1_w=inv0
R8_w=inv(id=0,smin_value=-2147483648,
smax_value=2147483647,
var32_off=(0x0; 0xffffffff))
19: (cd) if r1 s< r8 goto pc+16
R0=inv(id=0,smax_value=48,var32_off=(0x0; 0xffffffff))
R1_w=inv0
R8_w=inv(id=0,smin_value=-2147483648,
smax_value=0,
var32_off=(0x0; 0xffffffff))
20:
R0=inv(id=0,smax_value=48,var32_off=(0x0; 0xffffffff))
R1_w=inv0
R8_w=inv(id=0,smin_value=-2147483648,
smax_value=0,
R9=inv48
20: (1f) r9 -= r8
21: (bf) r2 = r7
22:
R2_w=map_value(id=0,off=0,ks=8,vs=48,imm=0)
22: (0f) r2 += r8
value -2147483648 makes map_value pointer be out of bounds
After call bpf_get_stack() on line 14 and some moves we have at line 16
an r8 bound with max_value 48 but an unknown min value. This is to be
expected bpf_get_stack call can only return a max of the input size but
is free to return any negative error in the 32-bit register space. The
C helper is returning an int so will use lower 32-bits.
Lines 17 and 18 clear the top 32 bits with a left/right shift but use
ARSH so we still have worst case min bound before line 19 of -2147483648.
At this point the signed check 'r1 s< r8' meant to protect the addition
on line 22 where dst reg is a map_value pointer may very well return
true with a large negative number. Then the final line 22 will detect
this as an invalid operation and fail the program. What we want to do
is proceed only if r8 is positive non-error. So change 'r1 s< r8' to
'r1 s> r8' so that we jump if r8 is negative.
Next we will throw an error because we access past the end of the map
value. The map value size is 48 and sizeof(struct test_val) is 48 so
we walk off the end of the map value on the second call to
get bpf_get_stack(). Fix this by changing sizeof(struct test_val) to
24 by using 'sizeof(struct test_val) / 2'. After this everything passes
as expected.
Signed-off-by: John Fastabend <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/158560426019.10843.3285429543232025187.stgit@john-Precision-5820-Tower
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Add various tests to make sure the verifier keeps catching them:
# ./test_verifier
[...]
#230/p pass ctx or null check, 1: ctx OK
#231/p pass ctx or null check, 2: null OK
#232/p pass ctx or null check, 3: 1 OK
#233/p pass ctx or null check, 4: ctx - const OK
#234/p pass ctx or null check, 5: null (connect) OK
#235/p pass ctx or null check, 6: null (bind) OK
#236/p pass ctx or null check, 7: ctx (bind) OK
#237/p pass ctx or null check, 8: null (bind) OK
[...]
Summary: 1595 PASSED, 0 SKIPPED, 0 FAILED
Signed-off-by: Daniel Borkmann <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/c74758d07b1b678036465ef7f068a49e9efd3548.1585323121.git.daniel@iogearbox.net
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After changes to add update_reg_bounds after ALU ops and adding ALU32
bounds tracking the error message is changed in the 32-bit right shift
tests.
Test "#70/u bounds check after 32-bit right shift with 64-bit input FAIL"
now fails with,
Unexpected error message!
EXP: R0 invalid mem access
RES: func#0 @0
7: (b7) r1 = 2
8: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0) R1_w=invP2 R10=fp0 fp-8_w=mmmmmmmm
8: (67) r1 <<= 31
9: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0) R1_w=invP4294967296 R10=fp0 fp-8_w=mmmmmmmm
9: (74) w1 >>= 31
10: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0) R1_w=invP0 R10=fp0 fp-8_w=mmmmmmmm
10: (14) w1 -= 2
11: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0) R1_w=invP4294967294 R10=fp0 fp-8_w=mmmmmmmm
11: (0f) r0 += r1
math between map_value pointer and 4294967294 is not allowed
And test "#70/p bounds check after 32-bit right shift with 64-bit input
FAIL" now fails with,
Unexpected error message!
EXP: R0 invalid mem access
RES: func#0 @0
7: (b7) r1 = 2
8: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0) R1_w=inv2 R10=fp0 fp-8_w=mmmmmmmm
8: (67) r1 <<= 31
9: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0) R1_w=inv4294967296 R10=fp0 fp-8_w=mmmmmmmm
9: (74) w1 >>= 31
10: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0) R1_w=inv0 R10=fp0 fp-8_w=mmmmmmmm
10: (14) w1 -= 2
11: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0) R1_w=inv4294967294 R10=fp0 fp-8_w=mmmmmmmm
11: (0f) r0 += r1
last_idx 11 first_idx 0
regs=2 stack=0 before 10: (14) w1 -= 2
regs=2 stack=0 before 9: (74) w1 >>= 31
regs=2 stack=0 before 8: (67) r1 <<= 31
regs=2 stack=0 before 7: (b7) r1 = 2
math between map_value pointer and 4294967294 is not allowed
Before this series we did not trip the "math between map_value pointer..."
error because check_reg_sane_offset is never called in
adjust_ptr_min_max_vals(). Instead we have a register state that looks
like this at line 11*,
11: R0_w=map_value(id=0,off=0,ks=8,vs=8,
smin_value=0,smax_value=0,
umin_value=0,umax_value=0,
var_off=(0x0; 0x0))
R1_w=invP(id=0,
smin_value=0,smax_value=4294967295,
umin_value=0,umax_value=4294967295,
var_off=(0xfffffffe; 0x0))
R10=fp(id=0,off=0,
smin_value=0,smax_value=0,
umin_value=0,umax_value=0,
var_off=(0x0; 0x0)) fp-8_w=mmmmmmmm
11: (0f) r0 += r1
In R1 'smin_val != smax_val' yet we have a tnum_const as seen
by 'var_off(0xfffffffe; 0x0))' with a 0x0 mask. So we hit this check
in adjust_ptr_min_max_vals()
if ((known && (smin_val != smax_val || umin_val != umax_val)) ||
smin_val > smax_val || umin_val > umax_val) {
/* Taint dst register if offset had invalid bounds derived from
* e.g. dead branches.
*/
__mark_reg_unknown(env, dst_reg);
return 0;
}
So we don't throw an error here and instead only throw an error
later in the verification when the memory access is made.
The root cause in verifier without alu32 bounds tracking is having
'umin_value = 0' and 'umax_value = U64_MAX' from BPF_SUB which we set
when 'umin_value < umax_val' here,
if (dst_reg->umin_value < umax_val) {
/* Overflow possible, we know nothing */
dst_reg->umin_value = 0;
dst_reg->umax_value = U64_MAX;
} else { ...}
Later in adjust_calar_min_max_vals we previously did a
coerce_reg_to_size() which will clamp the U64_MAX to U32_MAX by
truncating to 32bits. But either way without a call to update_reg_bounds
the less precise bounds tracking will fall out of the alu op
verification.
After latest changes we now exit adjust_scalar_min_max_vals with the
more precise umin value, due to zero extension propogating bounds from
alu32 bounds into alu64 bounds and then calling update_reg_bounds.
This then causes the verifier to trigger an earlier error and we get
the error in the output above.
This patch updates tests to reflect new error message.
* I have a local patch to print entire verifier state regardless if we
believe it is a constant so we can get a full picture of the state.
Usually if tnum_is_const() then bounds are also smin=smax, etc. but
this is not always true and is a bit subtle. Being able to see these
states helps understand dataflow imo. Let me know if we want something
similar upstream.
Signed-off-by: John Fastabend <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/158507161475.15666.3061518385241144063.stgit@john-Precision-5820-Tower
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Overlapping header include additions in macsec.c
A bug fix in 'net' overlapping with the removal of 'version'
string in ena_netdev.c
Overlapping test additions in selftests Makefile
Overlapping PCI ID table adjustments in iwlwifi driver.
Signed-off-by: David S. Miller <[email protected]>
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Add SPDX License Identifier to all .gitignore files.
Signed-off-by: Masahiro Yamada <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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The existing tests attempt to check that JMP32 JSET ignores the upper
bits in the operand registers. However, the tests missed one such bug in
the x32 JIT that is only uncovered when a previous instruction pollutes
the upper 32 bits of the registers.
This patch adds a new test case that catches the bug by first executing
a 64-bit JSET to pollute the upper 32-bits of the temporary registers,
followed by a 32-bit JSET which should ignore the upper 32 bits.
Co-developed-by: Xi Wang <[email protected]>
Signed-off-by: Xi Wang <[email protected]>
Signed-off-by: Luke Nelson <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Analogous to the gso_segs selftests introduced in commit d9ff286a0f59
("bpf: allow BPF programs access skb_shared_info->gso_segs field").
Signed-off-by: Willem de Bruijn <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Expand dummy prog generation such that we can easily check on return
codes and add few more test cases to make sure we keep on tracking
pruning behavior.
# ./test_verifier
[...]
#1066/p XDP pkt read, pkt_data <= pkt_meta', bad access 1 OK
#1067/p XDP pkt read, pkt_data <= pkt_meta', bad access 2 OK
Summary: 1580 PASSED, 0 SKIPPED, 0 FAILED
Also verified that JIT dump of added test cases looks good.
Signed-off-by: Daniel Borkmann <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/df7200b6021444fd369376d227de917357285b65.1576789878.git.daniel@iogearbox.net
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Three test cases are added.
Test 1: jmp32 'reg op imm'.
Test 2: jmp32 'reg op reg' where dst 'reg' has unknown constant
and src 'reg' has known constant
Test 3: jmp32 'reg op reg' where dst 'reg' has known constant
and src 'reg' has unknown constant
Signed-off-by: Yonghong Song <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Add a loop test with 32 bit register against 0 immediate:
# ./test_verifier 631
#631/p taken loop with back jump to 1st insn, 2 OK
Disassembly:
[...]
1b: test %edi,%edi
1d: jne 0x0000000000000014
[...]
Pretty much similar to prior "taken loop with back jump to 1st
insn" test case just as jmp32 variant.
Signed-off-by: Daniel Borkmann <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Acked-by: Song Liu <[email protected]>
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Daniel Borkmann says:
====================
The following pull-request contains BPF updates for your *net-next* tree.
The main changes are:
1) Add the ability to use unaligned chunks in the AF_XDP umem. By
relaxing where the chunks can be placed, it allows to use an
arbitrary buffer size and place whenever there is a free
address in the umem. Helps more seamless DPDK AF_XDP driver
integration. Support for i40e, ixgbe and mlx5e, from Kevin and
Maxim.
2) Addition of a wakeup flag for AF_XDP tx and fill rings so the
application can wake up the kernel for rx/tx processing which
avoids busy-spinning of the latter, useful when app and driver
is located on the same core. Support for i40e, ixgbe and mlx5e,
from Magnus and Maxim.
3) bpftool fixes for printf()-like functions so compiler can actually
enforce checks, bpftool build system improvements for custom output
directories, and addition of 'bpftool map freeze' command, from Quentin.
4) Support attaching/detaching XDP programs from 'bpftool net' command,
from Daniel.
5) Automatic xskmap cleanup when AF_XDP socket is released, and several
barrier/{read,write}_once fixes in AF_XDP code, from Björn.
6) Relicense of bpf_helpers.h/bpf_endian.h for future libbpf
inclusion as well as libbpf versioning improvements, from Andrii.
7) Several new BPF kselftests for verifier precision tracking, from Alexei.
8) Several BPF kselftest fixes wrt endianess to run on s390x, from Ilya.
9) And more BPF kselftest improvements all over the place, from Stanislav.
10) Add simple BPF map op cache for nfp driver to batch dumps, from Jakub.
11) AF_XDP socket umem mapping improvements for 32bit archs, from Ivan.
12) Add BPF-to-BPF call and BTF line info support for s390x JIT, from Yauheni.
13) Small optimization in arm64 JIT to spare 1 insns for BPF_MOD, from Jerin.
14) Fix an error check in bpf_tcp_gen_syncookie() helper, from Petar.
15) Various minor fixes and cleanups, from Nathan, Masahiro, Masanari,
Peter, Wei, Yue.
====================
Signed-off-by: David S. Miller <[email protected]>
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Add two tests to check that stack slot marking during backtracking
doesn't trigger 'spi > allocated_stack' warning.
One test is using BPF_ST insn. Another is using BPF_STX.
Signed-off-by: Alexei Starovoitov <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
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Copy-paste of existing test
"calls: cross frame pruning - liveness propagation"
but ran with different parentage chain heuristic
which stresses different path in precision tracking logic.
Signed-off-by: Alexei Starovoitov <[email protected]>
Acked-by: Song Liu <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
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