linux-stable.git/tools/lib/bpf, branch linux-5.14.y

libbpf: Fix lookup_and_delete_elem_flags error reporting

2021-11-17T10:04:40+00:00

[ Upstream commit 64165ddf8ea184631c65e3bbc8d59f6d940590ca ]

Fix bpf_map_lookup_and_delete_elem_flags() to pass the return code through
libbpf_err_errno() as we do similarly in bpf_map_lookup_and_delete_elem().

Fixes: f12b65432728 ("libbpf: Streamline error reporting for low-level APIs")
Signed-off-by: Mehrdad Arshad Rad 
Signed-off-by: Daniel Borkmann 
Acked-by: Yonghong Song 
Link: https://lore.kernel.org/bpf/20211104171354.11072-1-arshad.rad@gmail.com
Signed-off-by: Sasha Levin

libbpf: Fix endianness detection in BPF_CORE_READ_BITFIELD_PROBED()

2021-11-17T10:04:15+00:00

[ Upstream commit 45f2bebc8079788f62f22d9e8b2819afb1789d7b ]

__BYTE_ORDER is supposed to be defined by a libc, and __BYTE_ORDER__ -
by a compiler. bpf_core_read.h checks __BYTE_ORDER == __LITTLE_ENDIAN,
which is true if neither are defined, leading to incorrect behavior on
big-endian hosts if libc headers are not included, which is often the
case.

Fixes: ee26dade0e3b ("libbpf: Add support for relocatable bitfields")
Signed-off-by: Ilya Leoshkevich 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20211026010831.748682-2-iii@linux.ibm.com
Signed-off-by: Sasha Levin

libbpf: Fix BTF header parsing checks

2021-11-17T10:04:13+00:00

[ Upstream commit c825f5fee19caf301d9821cd79abaa734322de26 ]

Original code assumed fixed and correct BTF header length. That's not
always the case, though, so fix this bug with a proper additional check.
And use actual header length instead of sizeof(struct btf_header) in
sanity checks.

Fixes: 8a138aed4a80 ("bpf: btf: Add BTF support to libbpf")
Reported-by: Evgeny Vereshchagin 
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20211023003157.726961-2-andrii@kernel.org
Signed-off-by: Sasha Levin

libbpf: Fix overflow in BTF sanity checks

2021-11-17T10:04:13+00:00

[ Upstream commit 5245dafe3d49efba4d3285cf27ee1cc1eeafafc6 ]

btf_header's str_off+str_len or type_off+type_len can overflow as they
are u32s. This will lead to bypassing the sanity checks during BTF
parsing, resulting in crashes afterwards. Fix by using 64-bit signed
integers for comparison.

Fixes: d8123624506c ("libbpf: Fix BTF data layout checks and allow empty BTF")
Reported-by: Evgeny Vereshchagin 
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20211023003157.726961-1-andrii@kernel.org
Signed-off-by: Sasha Levin

libbpf: Fix memory leak in btf__dedup()

2021-11-17T10:04:13+00:00

[ Upstream commit 1000298c76830bc291358e98e8fa5baa3baa9b3a ]

Free btf_dedup if btf_ensure_modifiable() returns error.

Fixes: 919d2b1dbb07 ("libbpf: Allow modification of BTF and add btf__add_str API")
Signed-off-by: Mauricio Vásquez 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20211022202035.48868-1-mauricio@kinvolk.io
Signed-off-by: Sasha Levin

libbpf: Fix skel_internal.h to set errno on loader retval < 0

2021-11-17T10:04:01+00:00

[ Upstream commit e68ac0082787f4e8ee6ae5b19076ec7709ce715b ]

When the loader indicates an internal error (result of a checked bpf
system call), it returns the result in attr.test.retval. However, tests
that rely on ASSERT_OK_PTR on NULL (returned from light skeleton) may
miss that NULL denotes an error if errno is set to 0. This would result
in skel pointer being NULL, while ASSERT_OK_PTR returning 1, leading to
a SEGV on dereference of skel, because libbpf_get_error relies on the
assumption that errno is always set in case of error for ptr == NULL.

In particular, this was observed for the ksyms_module test. When
executed using `./test_progs -t ksyms`, prior tests manipulated errno
and the test didn't crash when it failed at ksyms_module load, while
using `./test_progs -t ksyms_module` crashed due to errno being
untouched.

Fixes: 67234743736a (libbpf: Generate loader program out of BPF ELF file.)
Signed-off-by: Kumar Kartikeya Dwivedi 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20210927145941.1383001-11-memxor@gmail.com
Signed-off-by: Sasha Levin

libbpf: Don't crash on object files with no symbol tables

2021-11-17T10:03:57+00:00

[ Upstream commit 03e601f48b2da6fb44d0f7b86957a8f6bacfb347 ]

If libbpf encounters an ELF file that has been stripped of its symbol
table, it will crash in bpf_object__add_programs() when trying to
dereference the obj->efile.symbols pointer.

Fix this by erroring out of bpf_object__elf_collect() if it is not able
able to find the symbol table.

v2:
  - Move check into bpf_object__elf_collect() and add nice error message

Fixes: 6245947c1b3c ("libbpf: Allow gaps in BPF program sections to support overriden weak functions")
Signed-off-by: Toke Høiland-Jørgensen 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20210901114812.204720-1-toke@redhat.com
Signed-off-by: Sasha Levin

libbpf: Fix memory leak in strset

2021-10-13T07:41:55+00:00

[ Upstream commit b0e875bac0fab3e7a7431c2eee36a8ccc0c712ac ]

Free struct strset itself, not just its internal parts.

Fixes: 90d76d3ececc ("libbpf: Extract internal set-of-strings datastructure APIs")
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Daniel Borkmann 
Acked-by: Martin KaFai Lau 
Link: https://lore.kernel.org/bpf/20211001185910.86492-1-andrii@kernel.org
Signed-off-by: Sasha Levin

libbpf: Fix segfault in light skeleton for objects without BTF

2021-10-13T07:41:55+00:00

[ Upstream commit 4729445b47efebf089da4ccbcd1b116ffa2ad4af ]

When fed an empty BPF object, bpftool gen skeleton -L crashes at
btf__set_fd() since it assumes presence of obj->btf, however for
the sequence below clang adds no .BTF section (hence no BTF).

Reproducer:

  $ touch a.bpf.c
  $ clang -O2 -g -target bpf -c a.bpf.c
  $ bpftool gen skeleton -L a.bpf.o
  /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
  /* THIS FILE IS AUTOGENERATED! */

  struct a_bpf {
	struct bpf_loader_ctx ctx;
  Segmentation fault (core dumped)

The same occurs for files compiled without BTF info, i.e. without
clang's -g flag.

Fixes: 67234743736a (libbpf: Generate loader program out of BPF ELF file.)
Signed-off-by: Kumar Kartikeya Dwivedi 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20210930061634.1840768-1-memxor@gmail.com
Signed-off-by: Sasha Levin

libbpf: Fix segfault in static linker for objects without BTF

2021-10-07T05:53:13+00:00

[ Upstream commit bcfd367c2839f2126c048fe59700ec1b538e2b06 ]

When a BPF object is compiled without BTF info (without -g),
trying to link such objects using bpftool causes a SIGSEGV due to
btf__get_nr_types accessing obj->btf which is NULL. Fix this by
checking for the NULL pointer, and return error.

Reproducer:
$ cat a.bpf.c
extern int foo(void);
int bar(void) { return foo(); }
$ cat b.bpf.c
int foo(void) { return 0; }
$ clang -O2 -target bpf -c a.bpf.c
$ clang -O2 -target bpf -c b.bpf.c
$ bpftool gen obj out a.bpf.o b.bpf.o
Segmentation fault (core dumped)

After fix:
$ bpftool gen obj out a.bpf.o b.bpf.o
libbpf: failed to find BTF info for object 'a.bpf.o'
Error: failed to link 'a.bpf.o': Unknown error -22 (-22)

Fixes: a46349227cd8 (libbpf: Add linker extern resolution support for functions and global variables)
Signed-off-by: Kumar Kartikeya Dwivedi 
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20210924023725.70228-1-memxor@gmail.com
Signed-off-by: Sasha Levin