Current libbpf Makefile does not contain the help command, which
is inconvenient to use. Similar to the Makefile help command of the
perf, a help command is provided to list the commands supported by
libbpf make and the functions of the commands.
Signed-off-by: Xin Liu <liuxin350@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221202081738.128513-1-liuxin350@huawei.com
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 <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20221130200013.2997831-1-andrii@kernel.org
Currently LLVM fails to recognize .data.* as data section and defaults to .text
section. Later BPF backend tries to emit 4-byte NOP instruction which doesn't
exist in BPF ISA and aborts.
The fix for LLVM is pending:
https://reviews.llvm.org/D138477
While waiting for the fix lets workaround the linked_list test case
by using .bss.* prefix which is properly recognized by LLVM as BSS section.
Fix libbpf to support .bss. prefix and adjust tests.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The perf build makes the install_headers target, however, as there is
no action for this target a warning is always produced of:
make[3]: Nothing to be done for 'install_headers'.
Solve this by adding a display of 'INSTALL libbpf_headers'.
Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Hao Luo <haoluo@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nicolas Schier <nicolas@fjasle.eu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: Stanislav Fomichev <sdf@google.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20221117004356.279422-3-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Coverity is reporting that btf_dump_name_dups() doesn't check return
result of hashmap__find() call. This is intentional, so make it explicit
with (void) cast.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20221117192824.4093553-1-andrii@kernel.org
The top two bits of size are used as busy and discard flags, so reject
the reservation that has any of these special bits in the size. With the
addition of validity check, these is also no need to check whether or
not total_size is overflowed.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221116072351.1168938-5-houtao@huaweicloud.com
Similar with the overflow problem on ringbuf mmap, in user_ringbuf_map()
2 * max_entries may overflow u32 when mapping writeable region.
Fixing it by casting the size of writable mmap region into a __u64 and
checking whether or not there will be overflow during mmap.
Fixes: b66ccae01f ("bpf: Add libbpf logic for user-space ring buffer")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221116072351.1168938-4-houtao@huaweicloud.com
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: bf99c936f9 ("libbpf: Add BPF ring buffer support")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221116072351.1168938-3-houtao@huaweicloud.com
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 <houtao1@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221116072351.1168938-2-houtao@huaweicloud.com
Fixed following checkpatch issues:
WARNING: Block comments use a trailing */ on a separate line
+ * other BPF program's BTF object */
WARNING: Possible repeated word: 'be'
+ * name. This is important to be be able to find corresponding BTF
ERROR: switch and case should be at the same indent
+ switch (ext->kcfg.sz) {
+ case 1: *(__u8 *)ext_val = value; break;
+ case 2: *(__u16 *)ext_val = value; break;
+ case 4: *(__u32 *)ext_val = value; break;
+ case 8: *(__u64 *)ext_val = value; break;
+ default:
ERROR: trailing statements should be on next line
+ case 1: *(__u8 *)ext_val = value; break;
ERROR: trailing statements should be on next line
+ case 2: *(__u16 *)ext_val = value; break;
ERROR: trailing statements should be on next line
+ case 4: *(__u32 *)ext_val = value; break;
ERROR: trailing statements should be on next line
+ case 8: *(__u64 *)ext_val = value; break;
ERROR: code indent should use tabs where possible
+ }$
WARNING: please, no spaces at the start of a line
+ }$
WARNING: Block comments use a trailing */ on a separate line
+ * for faster search */
ERROR: code indent should use tabs where possible
+^I^I^I^I^I^I &ext->kcfg.is_signed);$
WARNING: braces {} are not necessary for single statement blocks
+ if (err) {
+ return err;
+ }
ERROR: code indent should use tabs where possible
+^I^I^I^I sizeof(*obj->btf_modules), obj->btf_module_cnt + 1);$
Signed-off-by: Kang Minchul <tegongkang@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20221113190648.38556-3-tegongkang@gmail.com
We need to pass '*link' to final libbpf_get_error,
because that one holds the return value, not 'link'.
Fixes: 4fa5bcfe07 ("libbpf: Allow BPF program auto-attach handlers to bail out")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221114145257.882322-1-jolsa@kernel.org
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: 920d16af9b ("libbpf: BTF dumper support for typed data")
Signed-off-by: David Michael <fedora.dm0@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/87zgcu60hq.fsf@gmail.com
A fix for the LLVM compilation error while building bpftool.
Replaces the expression:
_Static_assert((p) == NULL || ...)
by expression:
_Static_assert((__builtin_constant_p((p)) ? (p) == NULL : 0) || ...)
When "p" is not a constant the former is not considered to be a
constant expression by LLVM 14.
The error was introduced in the following patch-set: [1].
The error was reported here: [2].
[1] https://lore.kernel.org/bpf/20221109142611.879983-1-eddyz87@gmail.com/
[2] https://lore.kernel.org/all/202211110355.BcGcbZxP-lkp@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
Fixes: c302378bc1 ("libbpf: Hashmap interface update to allow both long and void* keys/values")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20221110223240.1350810-1-eddyz87@gmail.com
Resolve forward declarations that don't take part in type graphs
comparisons if declaration name is unambiguous. Example:
CU #1:
struct foo; // standalone forward declaration
struct foo *some_global;
CU #2:
struct foo { int x; };
struct foo *another_global;
The `struct foo` from CU #1 is not a part of any definition that is
compared against another definition while `btf_dedup_struct_types`
processes structural types. The the BTF after `btf_dedup_struct_types`
the BTF looks as follows:
[1] STRUCT 'foo' size=4 vlen=1 ...
[2] INT 'int' size=4 ...
[3] PTR '(anon)' type_id=1
[4] FWD 'foo' fwd_kind=struct
[5] PTR '(anon)' type_id=4
This commit adds a new pass `btf_dedup_resolve_fwds`, that maps such
forward declarations to structs or unions with identical name in case
if the name is not ambiguous.
The pass is positioned before `btf_dedup_ref_types` so that types
[3] and [5] could be merged as a same type after [1] and [4] are merged.
The final result for the example above looks as follows:
[1] STRUCT 'foo' size=4 vlen=1
'x' type_id=2 bits_offset=0
[2] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED
[3] PTR '(anon)' type_id=1
For defconfig kernel with BTF enabled this removes 63 forward
declarations. Examples of removed declarations: `pt_regs`, `in6_addr`.
The running time of `btf__dedup` function is increased by about 3%.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221109142611.879983-3-eddyz87@gmail.com
An update for libbpf's hashmap interface from void* -> void* to a
polymorphic one, allowing both long and void* keys and values.
This simplifies many use cases in libbpf as hashmaps there are mostly
integer to integer.
Perf copies hashmap implementation from libbpf and has to be
updated as well.
Changes to libbpf, selftests/bpf and perf are packed as a single
commit to avoid compilation issues with any future bisect.
Polymorphic interface is acheived by hiding hashmap interface
functions behind auxiliary macros that take care of necessary
type casts, for example:
#define hashmap_cast_ptr(p) \
({ \
_Static_assert((p) == NULL || sizeof(*(p)) == sizeof(long),\
#p " pointee should be a long-sized integer or a pointer"); \
(long *)(p); \
})
bool hashmap_find(const struct hashmap *map, long key, long *value);
#define hashmap__find(map, key, value) \
hashmap_find((map), (long)(key), hashmap_cast_ptr(value))
- hashmap__find macro casts key and value parameters to long
and long* respectively
- hashmap_cast_ptr ensures that value pointer points to a memory
of appropriate size.
This hack was suggested by Andrii Nakryiko in [1].
This is a follow up for [2].
[1] https://lore.kernel.org/bpf/CAEf4BzZ8KFneEJxFAaNCCFPGqp20hSpS2aCj76uRk3-qZUH5xg@mail.gmail.com/
[2] https://lore.kernel.org/bpf/af1facf9-7bc8-8a3d-0db4-7b3f333589a2@meta.com/T/#m65b28f1d6d969fcd318b556db6a3ad499a42607d
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221109142611.879983-2-eddyz87@gmail.com
Changes de-duplication logic for enums in the following way:
- update btf_hash_enum to ignore size and kind fields to get
ENUM and ENUM64 types in a same hash bucket;
- update btf_compat_enum to consider enum fwd to be compatible with
full enum64 (and vice versa);
This allows BTF de-duplication in the following case:
// CU #1
enum foo;
struct s {
enum foo *a;
} *x;
// CU #2
enum foo {
x = 0xfffffffff // big enough to force enum64
};
struct s {
enum foo *a;
} *y;
De-duplicated BTF prior to this commit:
[1] ENUM64 'foo' encoding=UNSIGNED size=8 vlen=1
'x' val=68719476735ULL
[2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64
encoding=(none)
[3] STRUCT 's' size=8 vlen=1
'a' type_id=4 bits_offset=0
[4] PTR '(anon)' type_id=1
[5] PTR '(anon)' type_id=3
[6] STRUCT 's' size=8 vlen=1
'a' type_id=8 bits_offset=0
[7] ENUM 'foo' encoding=UNSIGNED size=4 vlen=0
[8] PTR '(anon)' type_id=7
[9] PTR '(anon)' type_id=6
De-duplicated BTF after this commit:
[1] ENUM64 'foo' encoding=UNSIGNED size=8 vlen=1
'x' val=68719476735ULL
[2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64
encoding=(none)
[3] STRUCT 's' size=8 vlen=1
'a' type_id=4 bits_offset=0
[4] PTR '(anon)' type_id=1
[5] PTR '(anon)' type_id=3
Enum forward declarations in C do not provide information about
enumeration values range. Thus the `btf_type->size` field is
meaningless for forward enum declarations. In fact, GCC does not
encode size in DWARF for forward enum declarations
(but dwarves sets enumeration size to a default value of `sizeof(int) * 8`
when size is not specified see dwarf_loader.c:die__create_new_enumeration).
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221101235413.1824260-1-eddyz87@gmail.com
Add support for new cgroup local storage.
Acked-by: David Vernet <void@manifault.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221026042856.673989-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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: efdd3eb801 ("libbpf: Accommodate DWARF/compiler bug with duplicated structs")
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
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
The reg_name in parse_usdt_arg() is used to hold register name, which
is short enough to be held in a 16-byte array, so we could define
reg_name as char reg_name[16] to avoid dynamically allocating reg_name
with sscanf.
Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20221018145538.2046842-1-xukuohai@huaweicloud.com
Teach libbpf to not add BPF_F_MMAPABLE flag unnecessarily for ARRAY maps
that are backing data sections, if such data sections don't expose any
variables to user-space. Exposed variables are those that have
STB_GLOBAL or STB_WEAK ELF binding and correspond to BTF VAR's
BTF_VAR_GLOBAL_ALLOCATED linkage.
The overall idea is that if some data section doesn't have any variable that
is exposed through BPF skeleton, then there is no reason to make such
BPF array mmapable. Making BPF array mmapable is not a free no-op
action, because BPF verifier doesn't allow users to put special objects
(such as BPF spin locks, RB tree nodes, linked list nodes, kptrs, etc;
anything that has a sensitive internal state that should not be modified
arbitrarily from user space) into mmapable arrays, as there is no way to
prevent user space from corrupting such sensitive state through direct
memory access through memory-mapped region.
By making sure that libbpf doesn't add BPF_F_MMAPABLE flag to BPF array
maps corresponding to data sections that only have static variables
(which are not supposed to be visible to user space according to libbpf
and BPF skeleton rules), users now can have spinlocks, kptrs, etc in
either default .bss/.data sections or custom .data.* sections (assuming
there are no global variables in such sections).
The only possible hiccup with this approach is the need to use global
variables during BPF static linking, even if it's not intended to be
shared with user space through BPF skeleton. To allow such scenarios,
extend libbpf's STV_HIDDEN ELF visibility attribute handling to
variables. Libbpf is already treating global hidden BPF subprograms as
static subprograms and adjusts BTF accordingly to make BPF verifier
verify such subprograms as static subprograms with preserving entire BPF
verifier state between subprog calls. This patch teaches libbpf to treat
global hidden variables as static ones and adjust BTF information
accordingly as well. This allows to share variables between multiple
object files during static linking, but still keep them internal to BPF
program and not get them exposed through BPF skeleton.
Note, that if the user has some advanced scenario where they absolutely
need BPF_F_MMAPABLE flag on .data/.bss/.rodata BPF array map despite
only having static variables, they still can achieve this by forcing it
through explicit bpf_map__set_map_flags() API.
Acked-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20221019002816.359650-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Refactor libbpf's BTF fixup step during BPF object open phase. The only
functional change is that we now ignore BTF_VAR_GLOBAL_EXTERN variables
during fix up, not just BTF_VAR_STATIC ones, which shouldn't cause any
change in behavior as there shouldn't be any extern variable in data
sections for valid BPF object anyways.
Otherwise it's just collapsing two functions that have no reason to be
separate, and switching find_elf_var_offset() helper to return entire
symbol pointer, not just its offset. This will be used by next patch to
get ELF symbol visibility.
While refactoring, also "normalize" debug messages inside
btf_fixup_datasec() to follow general libbpf style and print out data
section name consistently, where it's available.
Acked-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221019002816.359650-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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: db2b8b0642 ("libbpf: Support CO-RE relocations for multi-prog sections")
Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221012022353.7350-4-shung-hsi.yu@suse.com
ELF section data pointer returned by libelf may be NULL (if section has
SHT_NOBITS), so null check section data pointer before attempting to
copy license and kversion section.
Fixes: cb1e5e9619 ("bpf tools: Collect version and license from ELF sections")
Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221012022353.7350-3-shung-hsi.yu@suse.com
This commit replace e_shnum with the elf_getshdrnum() helper to fix two
oss-fuzz-reported heap-buffer overflow in __bpf_object__open. Both
reports are incorrectly marked as fixed and while still being
reproducible in the latest libbpf.
# clusterfuzz-testcase-minimized-bpf-object-fuzzer-5747922482888704
libbpf: loading object 'fuzz-object' from buffer
libbpf: sec_cnt is 0
libbpf: elf: section(1) .data, size 0, link 538976288, flags 2020202020202020, type=2
libbpf: elf: section(2) .data, size 32, link 538976288, flags 202020202020ff20, type=1
=================================================================
==13==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x6020000000c0 at pc 0x0000005a7b46 bp 0x7ffd12214af0 sp 0x7ffd12214ae8
WRITE of size 4 at 0x6020000000c0 thread T0
SCARINESS: 46 (4-byte-write-heap-buffer-overflow-far-from-bounds)
#0 0x5a7b45 in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3414:24
#1 0x5733c0 in bpf_object_open /src/libbpf/src/libbpf.c:7223:16
#2 0x5739fd in bpf_object__open_mem /src/libbpf/src/libbpf.c:7263:20
...
The issue lie in libbpf's direct use of e_shnum field in ELF header as
the section header count. Where as libelf implemented an extra logic
that, when e_shnum == 0 && e_shoff != 0, will use sh_size member of the
initial section header as the real section header count (part of ELF
spec to accommodate situation where section header counter is larger
than SHN_LORESERVE).
The above inconsistency lead to libbpf writing into a zero-entry calloc
area. So intead of using e_shnum directly, use the elf_getshdrnum()
helper provided by libelf to retrieve the section header counter into
sec_cnt.
Fixes: 0d6988e16a ("libbpf: Fix section counting logic")
Fixes: 25bbbd7a44 ("libbpf: Remove assumptions about uniqueness of .rodata/.data/.bss maps")
Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=40868
Link: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=40957
Link: https://lore.kernel.org/bpf/20221012022353.7350-2-shung-hsi.yu@suse.com
In the arm64 version of parse_usdt_arg(), when sscanf returns 2, reg_name
is allocated but not freed. Fix it.
Fixes: 0f8619929c ("libbpf: Usdt aarch64 arg parsing support")
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/bpf/20221011120108.782373-3-xukuohai@huaweicloud.com
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: 919d2b1dbb ("libbpf: Allow modification of BTF and add btf__add_str API")
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/bpf/20221011120108.782373-2-xukuohai@huaweicloud.com
Introduce bpf_link_get_fd_by_id_opts(), for symmetry with
bpf_map_get_fd_by_id_opts(), to let the caller pass the newly introduced
data structure bpf_get_fd_by_id_opts. Keep the existing
bpf_link_get_fd_by_id(), and call bpf_link_get_fd_by_id_opts() with NULL as
opts argument, to prevent setting open_flags.
Currently, the kernel does not support non-zero open_flags for
bpf_link_get_fd_by_id_opts(), and a call with them will result in an error
returned by the bpf() system call. The caller should always pass zero
open_flags.
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221006110736.84253-6-roberto.sassu@huaweicloud.com
Introduce bpf_btf_get_fd_by_id_opts(), for symmetry with
bpf_map_get_fd_by_id_opts(), to let the caller pass the newly introduced
data structure bpf_get_fd_by_id_opts. Keep the existing
bpf_btf_get_fd_by_id(), and call bpf_btf_get_fd_by_id_opts() with NULL as
opts argument, to prevent setting open_flags.
Currently, the kernel does not support non-zero open_flags for
bpf_btf_get_fd_by_id_opts(), and a call with them will result in an error
returned by the bpf() system call. The caller should always pass zero
open_flags.
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221006110736.84253-5-roberto.sassu@huaweicloud.com
Introduce bpf_prog_get_fd_by_id_opts(), for symmetry with
bpf_map_get_fd_by_id_opts(), to let the caller pass the newly introduced
data structure bpf_get_fd_by_id_opts. Keep the existing
bpf_prog_get_fd_by_id(), and call bpf_prog_get_fd_by_id_opts() with NULL as
opts argument, to prevent setting open_flags.
Currently, the kernel does not support non-zero open_flags for
bpf_prog_get_fd_by_id_opts(), and a call with them will result in an error
returned by the bpf() system call. The caller should always pass zero
open_flags.
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221006110736.84253-4-roberto.sassu@huaweicloud.com
Define a new data structure called bpf_get_fd_by_id_opts, with the member
open_flags, to be used by callers of the _opts variants of
bpf_*_get_fd_by_id() to specify the permissions needed for the file
descriptor to be obtained.
Also, introduce bpf_map_get_fd_by_id_opts(), to let the caller pass a
bpf_get_fd_by_id_opts structure.
Finally, keep the existing bpf_map_get_fd_by_id(), and call
bpf_map_get_fd_by_id_opts() with NULL as opts argument, to request
read-write permissions (current behavior).
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221006110736.84253-3-roberto.sassu@huaweicloud.com
btf_dump_emit_struct_def attempts to print empty structures at a
single line, e.g. `struct empty {}`. However, it has to account for a
case when there are no regular but some padding fields in the struct.
In such case `vlen` would be zero, but size would be non-zero.
E.g. here is struct bpf_timer from vmlinux.h before this patch:
struct bpf_timer {
long: 64;
long: 64;};
And after this patch:
struct bpf_dynptr {
long: 64;
long: 64;
};
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221001104425.415768-1-eddyz87@gmail.com
I accidentally found that a change in commit 1045b03e07 ("netlink: fix
overrun in attribute iteration") was not synchronized to the function
`nla_ok` in tools/lib/bpf/nlattr.c, I think it is necessary to modify,
this patch will do it.
Signed-off-by: Xin Liu <liuxin350@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220930090708.62394-1-liuxin350@huawei.com
Drop the requirement for system-wide kernel UAPI headers to provide full
struct btf_enum64 definition. This is an unexpected requirement that
slipped in libbpf 1.0 and put unnecessary pressure ([0]) on users to have
a bleeding-edge kernel UAPI header from unreleased Linux 6.0.
To achieve this, we forward declare struct btf_enum64. But that's not
enough as there is btf_enum64_value() helper that expects to know the
layout of struct btf_enum64. So we get a bit creative with
reinterpreting memory layout as array of __u32 and accesing lo32/hi32
fields as array elements. Alternative way would be to have a local
pointer variable for anonymous struct with exactly the same layout as
struct btf_enum64, but that gets us into C++ compiler errors complaining
about invalid type casts. So play it safe, if ugly.
[0] Closes: https://github.com/libbpf/libbpf/issues/562
Fixes: d90ec262b3 ("libbpf: Add enum64 support for btf_dump")
Reported-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Link: https://lore.kernel.org/bpf/20220927042940.147185-1-andrii@kernel.org
When running rootless with special capabilities like:
FOWNER / DAC_OVERRIDE / DAC_READ_SEARCH
The "access" API will not make the proper check if there is really
access to a file or not.
>From the access man page:
"
The check is done using the calling process's real UID and GID, rather
than the effective IDs as is done when actually attempting an operation
(e.g., open(2)) on the file. Similarly, for the root user, the check
uses the set of permitted capabilities rather than the set of effective
capabilities; ***and for non-root users, the check uses an empty set of
capabilities.***
"
What that means is that for non-root user the access API will not do the
proper validation if the process really has permission to a file or not.
To resolve this this patch replaces all the access API calls with
faccessat with AT_EACCESS flag.
Signed-off-by: Jon Doron <jond@wiz.io>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220925070431.1313680-1-arilou@gmail.com
When attach_prog_fd field was removed in libbpf 1.0 and replaced with
`long: 0` placeholder, it actually shifted all the subsequent fields by
8 byte. This is due to `long: 0` promising to adjust next field's offset
to long-aligned offset. But in this case we were already long-aligned
as pin_root_path is a pointer. So `long: 0` had no effect, and thus
didn't feel the gap created by removed attach_prog_fd.
Non-zero bitfield should have been used instead. I validated using
pahole. Originally kconfig field was at offset 40. With `long: 0` it's
at offset 32, which is wrong. With this change it's back at offset 40.
While technically libbpf 1.0 is allowed to break backwards
compatibility and applications should have been recompiled against
libbpf 1.0 headers, but given how trivial it is to preserve memory
layout, let's fix this.
Reported-by: Grant Seltzer Richman <grantseltzer@gmail.com>
Fixes: 146bf811f5 ("libbpf: remove most other deprecated high-level APIs")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220923230559.666608-1-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Currently, the default vmlinux files at '/boot/vmlinux-*',
'/lib/modules/*/vmlinux-*' etc. are parsed with 'btf__parse_elf()' to
extract BTF. It is possible that these files are actually raw BTF files
similar to /sys/kernel/btf/vmlinux. So parse these files with
'btf__parse' which tries both raw format and ELF format.
This might be useful in some scenarios where users put their custom BTF
into known locations and don't want to specify btf_custom_path option.
Signed-off-by: Tao Chen <chentao.kernel@linux.alibaba.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/3f59fb5a345d2e4f10e16fe9e35fbc4c03ecaa3e.1662999860.git.chentao.kernel@linux.alibaba.com
Commit 34586d29f8 ("libbpf: Add new BPF_PROG2 macro") added BPF_PROG2
macro for trampoline based programs with struct arguments. Andrii
made a few suggestions to improve code quality and description.
This patch implemented these suggestions including better internal
macro name, consistent usage pattern for __builtin_choose_expr(),
simpler macro definition for always-inline func arguments and
better macro description.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20220910025214.1536510-1-yhs@fb.com
Now that all of the logic is in place in the kernel to support user-space
produced ring buffers, we can add the user-space logic to libbpf. This
patch therefore adds the following public symbols to libbpf:
struct user_ring_buffer *
user_ring_buffer__new(int map_fd,
const struct user_ring_buffer_opts *opts);
void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size);
void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb,
__u32 size, int timeout_ms);
void user_ring_buffer__submit(struct user_ring_buffer *rb, void *sample);
void user_ring_buffer__discard(struct user_ring_buffer *rb,
void user_ring_buffer__free(struct user_ring_buffer *rb);
A user-space producer must first create a struct user_ring_buffer * object
with user_ring_buffer__new(), and can then reserve samples in the
ring buffer using one of the following two symbols:
void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size);
void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb,
__u32 size, int timeout_ms);
With user_ring_buffer__reserve(), a pointer to a 'size' region of the ring
buffer will be returned if sufficient space is available in the buffer.
user_ring_buffer__reserve_blocking() provides similar semantics, but will
block for up to 'timeout_ms' in epoll_wait if there is insufficient space
in the buffer. This function has the guarantee from the kernel that it will
receive at least one event-notification per invocation to
bpf_ringbuf_drain(), provided that at least one sample is drained, and the
BPF program did not pass the BPF_RB_NO_WAKEUP flag to bpf_ringbuf_drain().
Once a sample is reserved, it must either be committed to the ring buffer
with user_ring_buffer__submit(), or discarded with
user_ring_buffer__discard().
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220920000100.477320-4-void@manifault.com
We want to support a ringbuf map type where samples are published from
user-space, to be consumed by BPF programs. BPF currently supports a
kernel -> user-space circular ring buffer via the BPF_MAP_TYPE_RINGBUF
map type. We'll need to define a new map type for user-space -> kernel,
as none of the helpers exported for BPF_MAP_TYPE_RINGBUF will apply
to a user-space producer ring buffer, and we'll want to add one or
more helper functions that would not apply for a kernel-producer
ring buffer.
This patch therefore adds a new BPF_MAP_TYPE_USER_RINGBUF map type
definition. The map type is useless in its current form, as there is no
way to access or use it for anything until we one or more BPF helpers. A
follow-on patch will therefore add a new helper function that allows BPF
programs to run callbacks on samples that are published to the ring
buffer.
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220920000100.477320-2-void@manifault.com
We found that function btf_dump__dump_type_data can be called by the
user as an API, but in this function, the `opts` parameter may be used
as a null pointer.This causes `opts->indent_str` to trigger a NULL
pointer exception.
Fixes: 2ce8450ef5 ("libbpf: add bpf_object__open_{file, mem} w/ extensible opts")
Signed-off-by: Xin Liu <liuxin350@huawei.com>
Signed-off-by: Weibin Kong <kongweibin2@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220917084809.30770-1-liuxin350@huawei.com
Fix SIGSEGV caused by libbpf trying to find attach type in vmlinux BTF
for freplace programs. It's wrong to search in vmlinux BTF and libbpf
doesn't even mark vmlinux BTF as required for freplace programs. So
trying to search anything in obj->vmlinux_btf might cause NULL
dereference if nothing else in BPF object requires vmlinux BTF.
Instead, error out if freplace (EXT) program doesn't specify
attach_prog_fd during at the load time.
Fixes: 91abb4a6d7 ("libbpf: Support attachment of BPF tracing programs to kernel modules")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220909193053.577111-3-andrii@kernel.org
This reverts commit 14e5ce7994 ("libbpf: Add GCC support for
bpf_tail_call_static"). Reason is that gcc invented their own BPF asm
which is not conform with LLVM one, and going forward this would be
more painful to maintain here and in other areas of the library. Thus
remove it; ask to gcc folks is to align with LLVM one to use exact
same syntax.
Fixes: 14e5ce7994 ("libbpf: Add GCC support for bpf_tail_call_static")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: James Hilliard <james.hilliard1@gmail.com>
Cc: Jose E. Marchesi <jose.marchesi@oracle.com>
To support struct arguments in trampoline based programs,
existing BPF_PROG doesn't work any more since
the type size is needed to find whether a parameter
takes one or two registers. So this patch added a new
BPF_PROG2 macro to support such trampoline programs.
The idea is suggested by Andrii. For example, if the
to-be-traced function has signature like
typedef struct {
void *x;
int t;
} sockptr;
int blah(sockptr x, char y);
In the new BPF_PROG2 macro, the argument can be
represented as
__bpf_prog_call(
({ union {
struct { __u64 x, y; } ___z;
sockptr x;
} ___tmp = { .___z = { ctx[0], ctx[1] }};
___tmp.x;
}),
({ union {
struct { __u8 x; } ___z;
char y;
} ___tmp = { .___z = { ctx[2] }};
___tmp.y;
}));
In the above, the values stored on the stack are properly
assigned to the actual argument type value by using 'union'
magic. Note that the macro also works even if no arguments
are with struct types.
Note that new BPF_PROG2 works for both llvm16 and pre-llvm16
compilers where llvm16 supports bpf target passing value
with struct up to 16 byte size and pre-llvm16 will pass
by reference by storing values on the stack. With static functions
with struct argument as always inline, the compiler is able
to optimize and remove additional stack saving of struct values.
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220831152707.2079473-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The bpf_tail_call_static function is currently not defined unless
using clang >= 8.
To support bpf_tail_call_static on GCC we can check if __clang__ is
not defined to enable bpf_tail_call_static.
We need to use GCC assembly syntax when the compiler does not define
__clang__ as LLVM inline assembly is not fully compatible with GCC.
Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220829210546.755377-1-james.hilliard1@gmail.com
