linux-stable.git/tools/lib, branch v5.15.97

libbpf: Avoid enum forward-declarations in public API in C++ mode

2022-12-31T12:14:43+00:00

[ Upstream commit b42693415b86f608049cf1b4870adc1dc65e58b0 ]

C++ enum forward declarations are fundamentally not compatible with pure
C enum definitions, and so libbpf's use of `enum bpf_stats_type;`
forward declaration in libbpf/bpf.h public API header is causing C++
compilation issues.

More details can be found in [0], but it comes down to C++ supporting
enum forward declaration only with explicitly specified backing type:

  enum bpf_stats_type: int;

In C (and I believe it's a GCC extension also), such forward declaration
is simply:

  enum bpf_stats_type;

Further, in Linux UAPI this enum is defined in pure C way:

enum bpf_stats_type { BPF_STATS_RUN_TIME = 0; }

And even though in both cases backing type is int, which can be
confirmed by looking at DWARF information, for C++ compiler actual enum
definition and forward declaration are incompatible.

To eliminate this problem, for C++ mode define input argument as int,
which makes enum unnecessary in libbpf public header. This solves the
issue and as demonstrated by next patch doesn't cause any unwanted
compiler warnings, at least with default warnings setting.

  [0] https://stackoverflow.com/questions/42766839/c11-enum-forward-causes-underlying-type-mismatch
  [1] Closes: https://github.com/libbpf/libbpf/issues/249

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20221130200013.2997831-1-andrii@kernel.org
Signed-off-by: Sasha Levin

libbpf: Fix uninitialized warning in btf_dump_dump_type_data

2022-12-31T12:14:09+00:00

[ Upstream commit dfd0afbf151d85411b371e841f62b81ee5d1ca54 ]

GCC 11.3.0 fails to compile btf_dump.c due to the following error,
which seems to originate in btf_dump_struct_data where the returned
value would be uninitialized if btf_vlen returns zero.

btf_dump.c: In function ‘btf_dump_dump_type_data’:
btf_dump.c:2363:12: error: ‘err’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
 2363 |         if (err < 0)
      |            ^

Fixes: 920d16af9b42 ("libbpf: BTF dumper support for typed data")
Signed-off-by: David Michael 
Signed-off-by: Daniel Borkmann 
Acked-by: Stanislav Fomichev 
Acked-by: Alan Maguire 
Link: https://lore.kernel.org/bpf/87zgcu60hq.fsf@gmail.com
Signed-off-by: Sasha Levin

libbpf: Btf dedup identical struct test needs check for nested structs/arrays

2022-12-31T12:14:07+00:00

[ Upstream commit f3c51fe02c55bd944662714e5b91b96dc271ad9f ]

When examining module BTF, it is common to see core kernel structures
such as sk_buff, net_device duplicated in the module.  After adding
debug messaging to BTF it turned out that much of the problem
was down to the identical struct test failing during deduplication;
sometimes the compiler adds identical structs.  However
it turns out sometimes that type ids of identical struct members
can also differ, even when the containing structs are still identical.

To take an example, for struct sk_buff, debug messaging revealed
that the identical struct matching was failing for the anon
struct "headers"; specifically for the first field:

__u8       __pkt_type_offset[0]; /*   128     0 */

Looking at the code in BTF deduplication, we have code that guards
against the possibility of identical struct definitions, down to
type ids, and identical array definitions.  However in this case
we have a struct which is being defined twice but does not have
identical type ids since each duplicate struct has separate type
ids for the above array member.   A similar problem (though not
observed) could occur for struct-in-struct.

The solution is to make the "identical struct" test check members
not just for matching ids, but to also check if they in turn are
identical structs or arrays.

The results of doing this are quite dramatic (for some modules
at least); I see the number of type ids drop from around 10000
to just over 1000 in one module for example.

For testing use latest pahole or apply [1], otherwise dedups
can fail for the reasons described there.

Also fix return type of btf_dedup_identical_arrays() as
suggested by Andrii to match boolean return type used
elsewhere.

Fixes: efdd3eb8015e ("libbpf: Accommodate DWARF/compiler bug with duplicated structs")
Signed-off-by: Alan Maguire 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/1666622309-22289-1-git-send-email-alan.maguire@oracle.com

[1] https://lore.kernel.org/bpf/1666364523-9648-1-git-send-email-alan.maguire

Signed-off-by: Sasha Levin

libbpf: Fix null-pointer dereference in find_prog_by_sec_insn()

2022-12-31T12:14:06+00:00

[ Upstream commit d0d382f95a9270dcf803539d6781d6bd67e3f5b2 ]

When there are no program sections, obj->programs is left unallocated,
and find_prog_by_sec_insn()'s search lands on &obj->programs[0] == NULL,
and will cause null-pointer dereference in the following access to
prog->sec_idx.

Guard the search with obj->nr_programs similar to what's being done in
__bpf_program__iter() to prevent null-pointer access from happening.

Fixes: db2b8b06423c ("libbpf: Support CO-RE relocations for multi-prog sections")
Signed-off-by: Shung-Hsi Yu 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20221012022353.7350-4-shung-hsi.yu@suse.com
Signed-off-by: Sasha Levin

libbpf: Fix use-after-free in btf_dump_name_dups

2022-12-31T12:14:06+00:00

[ Upstream commit 93c660ca40b5d2f7c1b1626e955a8e9fa30e0749 ]

ASAN reports an use-after-free in btf_dump_name_dups:

ERROR: AddressSanitizer: heap-use-after-free on address 0xffff927006db at pc 0xaaaab5dfb618 bp 0xffffdd89b890 sp 0xffffdd89b928
READ of size 2 at 0xffff927006db thread T0
    #0 0xaaaab5dfb614 in __interceptor_strcmp.part.0 (test_progs+0x21b614)
    #1 0xaaaab635f144 in str_equal_fn tools/lib/bpf/btf_dump.c:127
    #2 0xaaaab635e3e0 in hashmap_find_entry tools/lib/bpf/hashmap.c:143
    #3 0xaaaab635e72c in hashmap__find tools/lib/bpf/hashmap.c:212
    #4 0xaaaab6362258 in btf_dump_name_dups tools/lib/bpf/btf_dump.c:1525
    #5 0xaaaab636240c in btf_dump_resolve_name tools/lib/bpf/btf_dump.c:1552
    #6 0xaaaab6362598 in btf_dump_type_name tools/lib/bpf/btf_dump.c:1567
    #7 0xaaaab6360b48 in btf_dump_emit_struct_def tools/lib/bpf/btf_dump.c:912
    #8 0xaaaab6360630 in btf_dump_emit_type tools/lib/bpf/btf_dump.c:798
    #9 0xaaaab635f720 in btf_dump__dump_type tools/lib/bpf/btf_dump.c:282
    #10 0xaaaab608523c in test_btf_dump_incremental tools/testing/selftests/bpf/prog_tests/btf_dump.c:236
    #11 0xaaaab6097530 in test_btf_dump tools/testing/selftests/bpf/prog_tests/btf_dump.c:875
    #12 0xaaaab6314ed0 in run_one_test tools/testing/selftests/bpf/test_progs.c:1062
    #13 0xaaaab631a0a8 in main tools/testing/selftests/bpf/test_progs.c:1697
    #14 0xffff9676d214 in __libc_start_main ../csu/libc-start.c:308
    #15 0xaaaab5d65990  (test_progs+0x185990)

0xffff927006db is located 11 bytes inside of 16-byte region [0xffff927006d0,0xffff927006e0)
freed by thread T0 here:
    #0 0xaaaab5e2c7c4 in realloc (test_progs+0x24c7c4)
    #1 0xaaaab634f4a0 in libbpf_reallocarray tools/lib/bpf/libbpf_internal.h:191
    #2 0xaaaab634f840 in libbpf_add_mem tools/lib/bpf/btf.c:163
    #3 0xaaaab636643c in strset_add_str_mem tools/lib/bpf/strset.c:106
    #4 0xaaaab6366560 in strset__add_str tools/lib/bpf/strset.c:157
    #5 0xaaaab6352d70 in btf__add_str tools/lib/bpf/btf.c:1519
    #6 0xaaaab6353e10 in btf__add_field tools/lib/bpf/btf.c:2032
    #7 0xaaaab6084fcc in test_btf_dump_incremental tools/testing/selftests/bpf/prog_tests/btf_dump.c:232
    #8 0xaaaab6097530 in test_btf_dump tools/testing/selftests/bpf/prog_tests/btf_dump.c:875
    #9 0xaaaab6314ed0 in run_one_test tools/testing/selftests/bpf/test_progs.c:1062
    #10 0xaaaab631a0a8 in main tools/testing/selftests/bpf/test_progs.c:1697
    #11 0xffff9676d214 in __libc_start_main ../csu/libc-start.c:308
    #12 0xaaaab5d65990  (test_progs+0x185990)

previously allocated by thread T0 here:
    #0 0xaaaab5e2c7c4 in realloc (test_progs+0x24c7c4)
    #1 0xaaaab634f4a0 in libbpf_reallocarray tools/lib/bpf/libbpf_internal.h:191
    #2 0xaaaab634f840 in libbpf_add_mem tools/lib/bpf/btf.c:163
    #3 0xaaaab636643c in strset_add_str_mem tools/lib/bpf/strset.c:106
    #4 0xaaaab6366560 in strset__add_str tools/lib/bpf/strset.c:157
    #5 0xaaaab6352d70 in btf__add_str tools/lib/bpf/btf.c:1519
    #6 0xaaaab6353ff0 in btf_add_enum_common tools/lib/bpf/btf.c:2070
    #7 0xaaaab6354080 in btf__add_enum tools/lib/bpf/btf.c:2102
    #8 0xaaaab6082f50 in test_btf_dump_incremental tools/testing/selftests/bpf/prog_tests/btf_dump.c:162
    #9 0xaaaab6097530 in test_btf_dump tools/testing/selftests/bpf/prog_tests/btf_dump.c:875
    #10 0xaaaab6314ed0 in run_one_test tools/testing/selftests/bpf/test_progs.c:1062
    #11 0xaaaab631a0a8 in main tools/testing/selftests/bpf/test_progs.c:1697
    #12 0xffff9676d214 in __libc_start_main ../csu/libc-start.c:308
    #13 0xaaaab5d65990  (test_progs+0x185990)

The reason is that the key stored in hash table name_map is a string
address, and the string memory is allocated by realloc() function, when
the memory is resized by realloc() later, the old memory may be freed,
so the address stored in name_map references to a freed memory, causing
use-after-free.

Fix it by storing duplicated string address in name_map.

Fixes: 919d2b1dbb07 ("libbpf: Allow modification of BTF and add btf__add_str API")
Signed-off-by: Xu Kuohai 
Signed-off-by: Andrii Nakryiko 
Acked-by: Martin KaFai Lau 
Link: https://lore.kernel.org/bpf/20221011120108.782373-2-xukuohai@huaweicloud.com
Signed-off-by: Sasha Levin

libbpf: Use page size as max_entries when probing ring buffer map

2022-12-19T11:36:41+00:00

[ Upstream commit 689eb2f1ba46b4b02195ac2a71c55b96d619ebf8 ]

Using page size as max_entries when probing ring buffer map, else the
probe may fail on host with 64KB page size (e.g., an ARM64 host).

After the fix, the output of "bpftool feature" on above host will be
correct.

Before :
    eBPF map_type ringbuf is NOT available
    eBPF map_type user_ringbuf is NOT available

After :
    eBPF map_type ringbuf is available
    eBPF map_type user_ringbuf is available

Signed-off-by: Hou Tao 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20221116072351.1168938-2-houtao@huaweicloud.com
Signed-off-by: Sasha Levin

libbpf: Handle size overflow for ringbuf mmap

2022-12-08T10:28:39+00:00

[ Upstream commit 927cbb478adf917e0a142b94baa37f06279cc466 ]

The maximum size of ringbuf is 2GB on x86-64 host, so 2 * max_entries
will overflow u32 when mapping producer page and data pages. Only
casting max_entries to size_t is not enough, because for 32-bits
application on 64-bits kernel the size of read-only mmap region
also could overflow size_t.

So fixing it by casting the size of read-only mmap region into a __u64
and checking whether or not there will be overflow during mmap.

Fixes: bf99c936f947 ("libbpf: Add BPF ring buffer support")
Signed-off-by: Hou Tao 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20221116072351.1168938-3-houtao@huaweicloud.com
Signed-off-by: Sasha Levin

selftests/xsk: Avoid use-after-free on ctx

2022-10-26T10:34:41+00:00

[ Upstream commit af515a5587b8f45f19e11657746e0c89411b0380 ]

The put lowers the reference count to 0 and frees ctx, reading it
afterwards is invalid. Move the put after the uses and determine the
last use by the reference count being 1.

Fixes: 39e940d4abfa ("selftests/xsk: Destroy BPF resources only when ctx refcount drops to 0")
Signed-off-by: Ian Rogers 
Signed-off-by: Daniel Borkmann 
Acked-by: Magnus Karlsson 
Link: https://lore.kernel.org/bpf/20220901202645.1463552-1-irogers@google.com
Signed-off-by: Sasha Levin

libbpf: fix an snprintf() overflow check

2022-08-17T12:23:32+00:00

[ Upstream commit b77ffb30cfc5f58e957571d8541c6a7e3da19221 ]

The snprintf() function returns the number of bytes it *would* have
copied if there were enough space.  So it can return > the
sizeof(gen->attach_target).

Fixes: 67234743736a ("libbpf: Generate loader program out of BPF ELF file.")
Signed-off-by: Dan Carpenter 
Acked-by: Martin KaFai Lau 
Link: https://lore.kernel.org/r/YtZ+oAySqIhFl6/J@kili
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin

libbpf: Fix the name of a reused map

2022-08-17T12:23:30+00:00

[ Upstream commit bf3f00378524adae16628cbadbd11ba7211863bb ]

BPF map name is limited to BPF_OBJ_NAME_LEN.
A map name is defined as being longer than BPF_OBJ_NAME_LEN,
it will be truncated to BPF_OBJ_NAME_LEN when a userspace program
calls libbpf to create the map. A pinned map also generates a path
in the /sys. If the previous program wanted to reuse the map，
it can not get bpf_map by name, because the name of the map is only
partially the same as the name which get from pinned path.

The syscall information below show that map name "process_pinned_map"
is truncated to "process_pinned_".

    bpf(BPF_OBJ_GET, {pathname="/sys/fs/bpf/process_pinned_map",
    bpf_fd=0, file_flags=0}, 144) = -1 ENOENT (No such file or directory)

    bpf(BPF_MAP_CREATE, {map_type=BPF_MAP_TYPE_HASH, key_size=4,
    value_size=4,max_entries=1024, map_flags=0, inner_map_fd=0,
    map_name="process_pinned_",map_ifindex=0, btf_fd=3, btf_key_type_id=6,
    btf_value_type_id=10,btf_vmlinux_value_type_id=0}, 72) = 4

This patch check that if the name of pinned map are the same as the
actual name for the first (BPF_OBJ_NAME_LEN - 1),
bpf map still uses the name which is included in bpf object.

Fixes: 26736eb9a483 ("tools: libbpf: allow map reuse")
Signed-off-by: Anquan Wu 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/OSZP286MB1725CEA1C95C5CB8E7CCC53FB8869@OSZP286MB1725.JPNP286.PROD.OUTLOOK.COM
Signed-off-by: Sasha Levin