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Tony Ambardar a9355b201d bpf: Fix libelf endian handling in resolv_btfids
[ Upstream commit 61e8aeda9398925f8c6fc290585bdd9727d154c4 ]

The vmlinux ".BTF_ids" ELF section is declared in btf_ids.h to hold a list
of zero-filled BTF IDs, which is then patched at link-time with correct
values by resolv_btfids. The section is flagged as "allocable" to preclude
compression, but notably the section contents (BTF IDs) are untyped.

When patching the BTF IDs, resolve_btfids writes in host-native endianness
and relies on libelf for any required translation on reading and updating
vmlinux. However, since the type of the .BTF_ids section content defaults
to ELF_T_BYTE (i.e. unsigned char), no translation occurs. This results in
incorrect patched values when cross-compiling to non-native endianness,
and can manifest as kernel Oops and test failures which are difficult to
troubleshoot [1].

Explicitly set the type of patched data to ELF_T_WORD, the architecture-
neutral ELF type corresponding to the u32 BTF IDs. This enables libelf to
transparently perform any needed endian conversions.

Fixes: fbbb68de80 ("bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object")
Signed-off-by: Tony Ambardar <Tony.Ambardar@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Frank Eigler <fche@redhat.com>
Cc: Mark Wielaard <mark@klomp.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/CAPGftE_eY-Zdi3wBcgDfkz_iOr1KF10n=9mJHm1_a_PykcsoeA@mail.gmail.com [1]
Link: https://lore.kernel.org/bpf/20210618061404.818569-1-Tony.Ambardar@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14 16:56:23 +02:00
arch x86/sev: Split up runtime #VC handler for correct state tracking 2021-07-14 16:56:09 +02:00
block blk-mq: update hctx->dispatch_busy in case of real scheduler 2021-07-14 16:56:13 +02:00
certs certs: Add ability to preload revocation certs 2021-06-30 08:47:30 -04:00
crypto crypto: sm2 - fix a memory leak in sm2 2021-07-14 16:56:06 +02:00
Documentation mm/debug_vm_pgtable/basic: add validation for dirtiness after write protect 2021-07-14 16:56:13 +02:00
drivers RDMA/rxe: Fix qp reference counting for atomic ops 2021-07-14 16:56:22 +02:00
fs dax: fix ENOMEM handling in grab_mapping_entry() 2021-07-14 16:56:13 +02:00
include xsk: Fix missing validation for skb and unaligned mode 2021-07-14 16:56:23 +02:00
init sched/core: Initialize the idle task with preemption disabled 2021-07-14 16:55:50 +02:00
ipc ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry 2021-05-26 12:06:54 +02:00
kernel psi: Fix race between psi_trigger_create/destroy 2021-07-14 16:56:10 +02:00
lib lockdep/selftests: Fix selftests vs PROVE_RAW_LOCK_NESTING 2021-07-14 16:56:10 +02:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm mm/page_alloc: fix counting of managed_pages 2021-07-14 16:56:14 +02:00
net xsk: Fix broken Tx ring validation 2021-07-14 16:56:23 +02:00
samples samples: vfio-mdev: fix error handing in mdpy_fb_probe() 2021-06-10 13:39:15 +02:00
scripts kbuild: Fix objtool dependency for 'OBJECT_FILES_NON_STANDARD_<obj> := n' 2021-07-14 16:56:04 +02:00
security evm: fix writing <securityfs>/evm overflow 2021-07-14 16:56:04 +02:00
sound ALSA: hda/realtek: fix mute/micmute LEDs for HP EliteBook 830 G8 Notebook PC 2021-07-14 16:55:37 +02:00
tools bpf: Fix libelf endian handling in resolv_btfids 2021-07-14 16:56:23 +02:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM: do not allow mapping valid but non-reference-counted pages 2021-06-30 08:47:25 -04:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore kbuild: generate Module.symvers only when vmlinux exists 2021-05-19 10:12:59 +02:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS f2fs: move ioctl interface definitions to separated file 2021-05-19 10:13:00 +02:00
Makefile Makefile: fix GDB warning with CONFIG_RELR 2021-07-14 16:55:53 +02:00
README

Linux kernel
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