summaryrefslogtreecommitdiffstats
path: root/tools/lib/bpf
Commit message (Collapse)AuthorAgeFilesLines
...
* bpf: improve error message for unsupported helperMykyta Yatsenko2024-03-281-2/+4
| | | | | | | | | | | | | | | | | BPF verifier emits "unknown func" message when given BPF program type does not support BPF helper. This message may be confusing for users, as important context that helper is unknown only to current program type is not provided. This patch changes message to "program of this type cannot use helper " and aligns dependent code in libbpf and tests. Any suggestions on improving/changing this message are welcome. Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Quentin Monnet <qmo@kernel.org> Link: https://lore.kernel.org/r/20240325152210.377548-1-yatsenko@meta.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski2024-03-281-3/+7
|\ | | | | | | | | | | | | | | Cross-merge networking fixes after downstream PR. No conflicts, or adjacent changes. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| * Merge tag 'for-netdev' of ↵Paolo Abeni2024-03-261-3/+7
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf Daniel Borkmann says: ==================== pull-request: bpf 2024-03-25 The following pull-request contains BPF updates for your *net* tree. We've added 17 non-merge commits during the last 12 day(s) which contain a total of 19 files changed, 184 insertions(+), 61 deletions(-). The main changes are: 1) Fix an arm64 BPF JIT bug in BPF_LDX_MEMSX implementation's offset handling found via test_bpf module, from Puranjay Mohan. 2) Various fixups to the BPF arena code in particular in the BPF verifier and around BPF selftests to match latest corresponding LLVM implementation, from Puranjay Mohan and Alexei Starovoitov. 3) Fix xsk to not assume that metadata is always requested in TX completion, from Stanislav Fomichev. 4) Fix riscv BPF JIT's kfunc parameter incompatibility between BPF and the riscv ABI which requires sign-extension on int/uint, from Pu Lehui. 5) Fix s390x BPF JIT's bpf_plt pointer arithmetic which triggered a crash when testing struct_ops, from Ilya Leoshkevich. 6) Fix libbpf's arena mmap handling which had incorrect u64-to-pointer cast on 32-bit architectures, from Andrii Nakryiko. 7) Fix libbpf to define MFD_CLOEXEC when not available, from Arnaldo Carvalho de Melo. 8) Fix arm64 BPF JIT implementation for 32bit unconditional bswap which resulted in an incorrect swap as indicated by test_bpf, from Artem Savkov. 9) Fix BPF man page build script to use silent mode, from Hangbin Liu. * tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: riscv, bpf: Fix kfunc parameters incompatibility between bpf and riscv abi bpf: verifier: reject addr_space_cast insn without arena selftests/bpf: verifier_arena: fix mmap address for arm64 bpf: verifier: fix addr_space_cast from as(1) to as(0) libbpf: Define MFD_CLOEXEC if not available arm64: bpf: fix 32bit unconditional bswap bpf, arm64: fix bug in BPF_LDX_MEMSX libbpf: fix u64-to-pointer cast on 32-bit arches s390/bpf: Fix bpf_plt pointer arithmetic xsk: Don't assume metadata is always requested in TX completion selftests/bpf: Add arena test case for 4Gbyte corner case selftests/bpf: Remove hard coded PAGE_SIZE macro. libbpf, selftests/bpf: Adjust libbpf, bpftool, selftests to match LLVM bpf: Clarify bpf_arena comments. MAINTAINERS: Update email address for Quentin Monnet scripts/bpf_doc: Use silent mode when exec make cmd bpf: Temporarily disable atomic operations in BPF arena ==================== Link: https://lore.kernel.org/r/20240325213520.26688-1-daniel@iogearbox.net Signed-off-by: Paolo Abeni <pabeni@redhat.com>
| | * libbpf: Define MFD_CLOEXEC if not availableArnaldo Carvalho de Melo2024-03-211-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since its going directly to the syscall to avoid not having memfd_create() available in some systems, do the same for its MFD_CLOEXEC flags, defining it if not available. This fixes the build in those systems, noticed while building perf on a set of build containers. Fixes: 9fa5e1a180aa639f ("libbpf: Call memfd_create() syscall directly") Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/ZfxZ9nCyKvwmpKkE@x1
| | * libbpf: fix u64-to-pointer cast on 32-bit archesAndrii Nakryiko2024-03-191-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It's been reported that (void *)map->map_extra is causing compilation warnings on 32-bit architectures. It's easy enough to fix this by casting to long first. Fixes: 79ff13e99169 ("libbpf: Add support for bpf_arena.") Reported-by: Ryan Eatmon <reatmon@ti.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Message-ID: <20240319215143.1279312-1-andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| | * libbpf, selftests/bpf: Adjust libbpf, bpftool, selftests to match LLVMAlexei Starovoitov2024-03-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The selftests use to tell LLVM about special pointers. For LLVM there is nothing "arena" about them. They are simply pointers in a different address space. Hence LLVM diff https://github.com/llvm/llvm-project/pull/85161 renamed: . macro __BPF_FEATURE_ARENA_CAST -> __BPF_FEATURE_ADDR_SPACE_CAST . global variables in __attribute__((address_space(N))) are now placed in section named ".addr_space.N" instead of ".arena.N". Adjust libbpf, bpftool, and selftests to match LLVM. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/bpf/20240315021834.62988-3-alexei.starovoitov@gmail.com
* | | Merge tag 'for-netdev' of ↵Jakub Kicinski2024-03-275-21/+128
|\ \ \ | |/ / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next Daniel Borkmann says: ==================== pull-request: bpf-next 2024-03-25 We've added 38 non-merge commits during the last 13 day(s) which contain a total of 50 files changed, 867 insertions(+), 274 deletions(-). The main changes are: 1) Add the ability to specify and retrieve BPF cookie also for raw tracepoint programs in order to ease migration from classic to raw tracepoints, from Andrii Nakryiko. 2) Allow the use of bpf_get_{ns_,}current_pid_tgid() helper for all program types and add additional BPF selftests, from Yonghong Song. 3) Several improvements to bpftool and its build, for example, enabling libbpf logs when loading pid_iter in debug mode, from Quentin Monnet. 4) Check the return code of all BPF-related set_memory_*() functions during load and bail out in case they fail, from Christophe Leroy. 5) Avoid a goto in regs_refine_cond_op() such that the verifier can be better integrated into Agni tool which doesn't support backedges yet, from Harishankar Vishwanathan. 6) Add a small BPF trie perf improvement by always inlining longest_prefix_match, from Jesper Dangaard Brouer. 7) Small BPF selftest refactor in bpf_tcp_ca.c to utilize start_server() helper instead of open-coding it, from Geliang Tang. 8) Improve test_tc_tunnel.sh BPF selftest to prevent client connect before the server bind, from Alessandro Carminati. 9) Fix BPF selftest benchmark for older glibc and use syscall(SYS_gettid) instead of gettid(), from Alan Maguire. 10) Implement a backward-compatible method for struct_ops types with additional fields which are not present in older kernels, from Kui-Feng Lee. 11) Add a small helper to check if an instruction is addr_space_cast from as(0) to as(1) and utilize it in x86-64 JIT, from Puranjay Mohan. 12) Small cleanup to remove unnecessary error check in bpf_struct_ops_map_update_elem, from Martin KaFai Lau. 13) Improvements to libbpf fd validity checks for BPF map/programs, from Mykyta Yatsenko. * tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (38 commits) selftests/bpf: Fix flaky test btf_map_in_map/lookup_update bpf: implement insn_is_cast_user() helper for JITs bpf: Avoid get_kernel_nofault() to fetch kprobe entry IP selftests/bpf: Use start_server in bpf_tcp_ca bpf: Sync uapi bpf.h to tools directory libbpf: Add new sec_def "sk_skb/verdict" selftests/bpf: Mark uprobe trigger functions with nocf_check attribute selftests/bpf: Use syscall(SYS_gettid) instead of gettid() wrapper in bench bpf-next: Avoid goto in regs_refine_cond_op() bpftool: Clean up HOST_CFLAGS, HOST_LDFLAGS for bootstrap bpftool selftests/bpf: scale benchmark counting by using per-CPU counters bpftool: Remove unnecessary source files from bootstrap version bpftool: Enable libbpf logs when loading pid_iter in debug mode selftests/bpf: add raw_tp/tp_btf BPF cookie subtests libbpf: add support for BPF cookie for raw_tp/tp_btf programs bpf: support BPF cookie in raw tracepoint (raw_tp, tp_btf) programs bpf: pass whole link instead of prog when triggering raw tracepoint bpf: flatten bpf_probe_register call chain selftests/bpf: Prevent client connect before server bind in test_tc_tunnel.sh selftests/bpf: Add a sk_msg prog bpf_get_ns_current_pid_tgid() test ... ==================== Link: https://lore.kernel.org/r/20240325233940.7154-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| * | libbpf: Add new sec_def "sk_skb/verdict"Yonghong Song2024-03-221-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The new sec_def specifies sk_skb program type with BPF_SK_SKB_VERDICT attachment type. This way, libbpf will set expected_attach_type properly for the program. Signed-off-by: Yonghong Song <yonghong.song@linux.dev> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240319175412.2941149-1-yonghong.song@linux.dev
| * | libbpf: add support for BPF cookie for raw_tp/tp_btf programsAndrii Nakryiko2024-03-195-5/+53
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Wire up BPF cookie passing or raw_tp and tp_btf programs, both in low-level and high-level APIs. Acked-by: Stanislav Fomichev <sdf@google.com> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Message-ID: <20240319233852.1977493-5-andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| * | libbpbpf: Check bpf_map/bpf_program fd validityMykyta Yatsenko2024-03-181-7/+52
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | libbpf creates bpf_program/bpf_map structs for each program/map that user defines, but it allows to disable creating/loading those objects in kernel, in that case they won't have associated file descriptor (fd < 0). Such functionality is used for backward compatibility with some older kernels. Nothing prevents users from passing these maps or programs with no kernel counterpart to libbpf APIs. This change introduces explicit checks for kernel objects existence, aiming to improve visibility of those edge cases and provide meaningful warnings to users. Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240318131808.95959-1-yatsenko@meta.com
| * | libbpf: Skip zeroed or null fields if not found in the kernel type.Kui-Feng Lee2024-03-141-5/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Accept additional fields of a struct_ops type with all zero values even if these fields are not in the corresponding type in the kernel. This provides a way to be backward compatible. User space programs can use the same map on a machine running an old kernel by clearing fields that do not exist in the kernel. Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240313214139.685112-2-thinker.li@gmail.com
| * | libbpf: Prevent null-pointer dereference when prog to load has no BTFQuentin Monnet2024-03-141-4/+3
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In bpf_objec_load_prog(), there's no guarantee that obj->btf is non-NULL when passing it to btf__fd(), and this function does not perform any check before dereferencing its argument (as bpf_object__btf_fd() used to do). As a consequence, we get segmentation fault errors in bpftool (for example) when trying to load programs that come without BTF information. v2: Keep btf__fd() in the fix instead of reverting to bpf_object__btf_fd(). Fixes: df7c3f7d3a3d ("libbpf: make uniform use of btf__fd() accessor inside libbpf") Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Quentin Monnet <qmo@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240314150438.232462-1-qmo@kernel.org
* | Merge tag 'kbuild-v6.9' of ↵Linus Torvalds2024-03-211-1/+1
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Generate a list of built DTB files (arch/*/boot/dts/dtbs-list) - Use more threads when building Debian packages in parallel - Fix warnings shown during the RPM kernel package uninstallation - Change OBJECT_FILES_NON_STANDARD_*.o etc. to take a relative path to Makefile - Support GCC's -fmin-function-alignment flag - Fix a null pointer dereference bug in modpost - Add the DTB support to the RPM package - Various fixes and cleanups in Kconfig * tag 'kbuild-v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (67 commits) kconfig: tests: test dependency after shuffling choices kconfig: tests: add a test for randconfig with dependent choices kconfig: tests: support KCONFIG_SEED for the randconfig runner kbuild: rpm-pkg: add dtb files in kernel rpm kconfig: remove unneeded menu_is_visible() call in conf_write_defconfig() kconfig: check prompt for choice while parsing kconfig: lxdialog: remove unused dialog colors kconfig: lxdialog: fix button color for blackbg theme modpost: fix null pointer dereference kbuild: remove GCC's default -Wpacked-bitfield-compat flag kbuild: unexport abs_srctree and abs_objtree kbuild: Move -Wenum-{compare-conditional,enum-conversion} into W=1 kconfig: remove named choice support kconfig: use linked list in get_symbol_str() to iterate over menus kconfig: link menus to a symbol kbuild: fix inconsistent indentation in top Makefile kbuild: Use -fmin-function-alignment when available alpha: merge two entries for CONFIG_ALPHA_GAMMA alpha: merge two entries for CONFIG_ALPHA_EV4 kbuild: change DTC_FLAGS_<basetarget>.o to take the path relative to $(obj) ...
| * kbuild: unexport abs_srctree and abs_objtreeMasahiro Yamada2024-03-101-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 25b146c5b8ce ("kbuild: allow Kbuild to start from any directory") exported abs_srctree and abs_objtree to avoid recomputation after the sub-make. However, this approach turned out to be fragile. Commit 5fa94ceb793e ("kbuild: set correct abs_srctree and abs_objtree for package builds") moved them above "ifneq ($(sub_make_done),1)", eliminating the need for exporting them. These are only needed in the top Makefile. If an absolute path is required in sub-directories, you can use $(abspath ) or $(realpath ) as needed. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
* | libbpf: Recognize __arena global variables.Andrii Nakryiko2024-03-112-13/+107
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | LLVM automatically places __arena variables into ".arena.1" ELF section. In order to use such global variables bpf program must include definition of arena map in ".maps" section, like: struct { __uint(type, BPF_MAP_TYPE_ARENA); __uint(map_flags, BPF_F_MMAPABLE); __uint(max_entries, 1000); /* number of pages */ __ulong(map_extra, 2ull << 44); /* start of mmap() region */ } arena SEC(".maps"); libbpf recognizes both uses of arena and creates single `struct bpf_map *` instance in libbpf APIs. ".arena.1" ELF section data is used as initial data image, which is exposed through skeleton and bpf_map__initial_value() to the user, if they need to tune it before the load phase. During load phase, this initial image is copied over into mmap()'ed region corresponding to arena, and discarded. Few small checks here and there had to be added to make sure this approach works with bpf_map__initial_value(), mostly due to hard-coded assumption that map->mmaped is set up with mmap() syscall and should be munmap()'ed. For arena, .arena.1 can be (much) smaller than maximum arena size, so this smaller data size has to be tracked separately. Given it is enforced that there is only one arena for entire bpf_object instance, we just keep it in a separate field. This can be generalized if necessary later. All global variables from ".arena.1" section are accessible from user space via skel->arena->name_of_var. For bss/data/rodata the skeleton/libbpf perform the following sequence: 1. addr = mmap(MAP_ANONYMOUS) 2. user space optionally modifies global vars 3. map_fd = bpf_create_map() 4. bpf_update_map_elem(map_fd, addr) // to store values into the kernel 5. mmap(addr, MAP_FIXED, map_fd) after step 5 user spaces see the values it wrote at step 2 at the same addresses arena doesn't support update_map_elem. Hence skeleton/libbpf do: 1. addr = malloc(sizeof SEC ".arena.1") 2. user space optionally modifies global vars 3. map_fd = bpf_create_map(MAP_TYPE_ARENA) 4. real_addr = mmap(map->map_extra, MAP_SHARED | MAP_FIXED, map_fd) 5. memcpy(real_addr, addr) // this will fault-in and allocate pages At the end look and feel of global data vs __arena global data is the same from bpf prog pov. Another complication is: struct { __uint(type, BPF_MAP_TYPE_ARENA); } arena SEC(".maps"); int __arena foo; int bar; ptr1 = &foo; // relocation against ".arena.1" section ptr2 = &arena; // relocation against ".maps" section ptr3 = &bar; // relocation against ".bss" section Fo the kernel ptr1 and ptr2 has point to the same arena's map_fd while ptr3 points to a different global array's map_fd. For the verifier: ptr1->type == unknown_scalar ptr2->type == const_ptr_to_map ptr3->type == ptr_to_map_value After verification, from JIT pov all 3 ptr-s are normal ld_imm64 insns. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Quentin Monnet <quentin@isovalent.com> Link: https://lore.kernel.org/bpf/20240308010812.89848-11-alexei.starovoitov@gmail.com
* | libbpf: Add support for bpf_arena.Alexei Starovoitov2024-03-112-8/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | mmap() bpf_arena right after creation, since the kernel needs to remember the address returned from mmap. This is user_vm_start. LLVM will generate bpf_arena_cast_user() instructions where necessary and JIT will add upper 32-bit of user_vm_start to such pointers. Fix up bpf_map_mmap_sz() to compute mmap size as map->value_size * map->max_entries for arrays and PAGE_SIZE * map->max_entries for arena. Don't set BTF at arena creation time, since it doesn't support it. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240308010812.89848-9-alexei.starovoitov@gmail.com
* | libbpf: Add __arg_arena to bpf_helpers.hAlexei Starovoitov2024-03-111-0/+1
| | | | | | | | | | | | | | | | | | | | Add __arg_arena to bpf_helpers.h Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240308010812.89848-8-alexei.starovoitov@gmail.com
* | libbpf: Allow specifying 64-bit integers in map BTF.Alexei Starovoitov2024-03-072-2/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __uint() macro that is used to specify map attributes like: __uint(type, BPF_MAP_TYPE_ARRAY); __uint(map_flags, BPF_F_MMAPABLE); It is limited to 32-bit, since BTF_KIND_ARRAY has u32 "number of elements" field in "struct btf_array". Introduce __ulong() macro that allows specifying values bigger than 32-bit. In map definition "map_extra" is the only u64 field, so far. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/r/20240307031228.42896-5-alexei.starovoitov@gmail.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
* | libbpf: Rewrite btf datasec names starting from '?'Eduard Zingerman2024-03-063-2/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Optional struct_ops maps are defined using question mark at the start of the section name, e.g.: SEC("?.struct_ops") struct test_ops optional_map = { ... }; This commit teaches libbpf to detect if kernel allows '?' prefix in datasec names, and if it doesn't then to rewrite such names by replacing '?' with '_', e.g.: DATASEC ?.struct_ops -> DATASEC _.struct_ops Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240306104529.6453-13-eddyz87@gmail.com
* | libbpf: Struct_ops in SEC("?.struct_ops") / SEC("?.struct_ops.link")Eduard Zingerman2024-03-061-1/+14
| | | | | | | | | | | | | | | | | | | | | | | | Allow using two new section names for struct_ops maps: - SEC("?.struct_ops") - SEC("?.struct_ops.link") To specify maps that have bpf_map->autocreate == false after open. Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240306104529.6453-12-eddyz87@gmail.com
* | libbpf: Replace elf_state->st_ops_* fields with SEC_ST_OPS sec_typeEduard Zingerman2024-03-061-29/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The next patch would add two new section names for struct_ops maps. To make working with multiple struct_ops sections more convenient: - remove fields like elf_state->st_ops_{shndx,link_shndx}; - mark section descriptions hosting struct_ops as elf_sec_desc->sec_type == SEC_ST_OPS; After these changes struct_ops sections could be processed uniformly by iterating bpf_object->efile.secs entries. Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240306104529.6453-11-eddyz87@gmail.com
* | libbpf: Sync progs autoload with maps autocreate for struct_ops mapsEduard Zingerman2024-03-061-0/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Automatically select which struct_ops programs to load depending on which struct_ops maps are selected for automatic creation. E.g. for the BPF code below: SEC("struct_ops/test_1") int BPF_PROG(foo) { ... } SEC("struct_ops/test_2") int BPF_PROG(bar) { ... } SEC(".struct_ops.link") struct test_ops___v1 A = { .foo = (void *)foo }; SEC(".struct_ops.link") struct test_ops___v2 B = { .foo = (void *)foo, .bar = (void *)bar, }; And the following libbpf API calls: bpf_map__set_autocreate(skel->maps.A, true); bpf_map__set_autocreate(skel->maps.B, false); The autoload would be enabled for program 'foo' and disabled for program 'bar'. During load, for each struct_ops program P, referenced from some struct_ops map M: - set P.autoload = true if M.autocreate is true for some M; - set P.autoload = false if M.autocreate is false for all M; - don't change P.autoload, if P is not referenced from any map. Do this after bpf_object__init_kern_struct_ops_maps() to make sure that shadow vars assignment is done. Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240306104529.6453-9-eddyz87@gmail.com
* | libbpf: Honor autocreate flag for struct_ops mapsEduard Zingerman2024-03-061-3/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Skip load steps for struct_ops maps not marked for automatic creation. This should allow to load bpf object in situations like below: SEC("struct_ops/foo") int BPF_PROG(foo) { ... } SEC("struct_ops/bar") int BPF_PROG(bar) { ... } struct test_ops___v1 { int (*foo)(void); }; struct test_ops___v2 { int (*foo)(void); int (*does_not_exist)(void); }; SEC(".struct_ops.link") struct test_ops___v1 map_for_old = { .test_1 = (void *)foo }; SEC(".struct_ops.link") struct test_ops___v2 map_for_new = { .test_1 = (void *)foo, .does_not_exist = (void *)bar }; Suppose program is loaded on old kernel that does not have definition for 'does_not_exist' struct_ops member. After this commit it would be possible to load such object file after the following tweaks: bpf_program__set_autoload(skel->progs.bar, false); bpf_map__set_autocreate(skel->maps.map_for_new, false); Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/bpf/20240306104529.6453-4-eddyz87@gmail.com
* | libbpf: Tie struct_ops programs to kernel BTF ids, not to local idsEduard Zingerman2024-03-061-23/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Enforce the following existing limitation on struct_ops programs based on kernel BTF id instead of program-local BTF id: struct_ops BPF prog can be re-used between multiple .struct_ops & .struct_ops.link as long as it's the same struct_ops struct definition and the same function pointer field This allows reusing same BPF program for versioned struct_ops map definitions, e.g.: SEC("struct_ops/test") int BPF_PROG(foo) { ... } struct some_ops___v1 { int (*test)(void); }; struct some_ops___v2 { int (*test)(void); }; SEC(".struct_ops.link") struct some_ops___v1 a = { .test = foo } SEC(".struct_ops.link") struct some_ops___v2 b = { .test = foo } Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240306104529.6453-3-eddyz87@gmail.com
* | libbpf: Allow version suffixes (___smth) for struct_ops typesEduard Zingerman2024-03-061-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | E.g. allow the following struct_ops definitions: struct bpf_testmod_ops___v1 { int (*test)(void); }; struct bpf_testmod_ops___v2 { int (*test)(void); }; SEC(".struct_ops.link") struct bpf_testmod_ops___v1 a = { .test = ... } SEC(".struct_ops.link") struct bpf_testmod_ops___v2 b = { .test = ... } Where both bpf_testmod_ops__v1 and bpf_testmod_ops__v2 would be resolved as 'struct bpf_testmod_ops' from kernel BTF. Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: David Vernet <void@manifault.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240306104529.6453-2-eddyz87@gmail.com
* | libbpf: Correct debug message in btf__load_vmlinux_btfChen Shen2024-03-041-1/+1
| | | | | | | | | | | | | | | | | | | | In the function btf__load_vmlinux_btf, the debug message incorrectly refers to 'path' instead of 'sysfs_btf_path'. Signed-off-by: Chen Shen <peterchenshen@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/bpf/20240302062218.3587-1-peterchenshen@gmail.com
* | libbpf: Convert st_ops->data to shadow type.Kui-Feng Lee2024-02-291-2/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Convert st_ops->data to the shadow type of the struct_ops map. The shadow type of a struct_ops type is a variant of the original struct type providing a way to access/change the values in the maps of the struct_ops type. bpf_map__initial_value() will return st_ops->data for struct_ops types. The skeleton is going to use it as the pointer to the shadow type of the original struct type. One of the main differences between the original struct type and the shadow type is that all function pointers of the shadow type are converted to pointers of struct bpf_program. Users can replace these bpf_program pointers with other BPF programs. The st_ops->progs[] will be updated before updating the value of a map to reflect the changes made by users. Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240229064523.2091270-3-thinker.li@gmail.com
* | libbpf: Set btf_value_type_id of struct bpf_map for struct_ops.Kui-Feng Lee2024-02-291-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | For a struct_ops map, btf_value_type_id is the type ID of it's struct type. This value is required by bpftool to generate skeleton including pointers of shadow types. The code generator gets the type ID from bpf_map__btf_value_type_id() in order to get the type information of the struct type of a map. Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240229064523.2091270-2-thinker.li@gmail.com
* | bpf: Clarify batch lookup/lookup_and_delete semanticsMartin Kelly2024-02-221-5/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The batch lookup and lookup_and_delete APIs have two parameters, in_batch and out_batch, to facilitate iterative lookup/lookup_and_deletion operations for supported maps. Except NULL for in_batch at the start of these two batch operations, both parameters need to point to memory equal or larger than the respective map key size, except for various hashmaps (hash, percpu_hash, lru_hash, lru_percpu_hash) where the in_batch/out_batch memory size should be at least 4 bytes. Document these semantics to clarify the API. Signed-off-by: Martin Kelly <martin.kelly@crowdstrike.com> Acked-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20240221211838.1241578-1-martin.kelly@crowdstrike.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
* | libbpf: Make remark about zero-initializing bpf_*_info structsMatt Bobrowski2024-02-141-5/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In some situations, if you fail to zero-initialize the bpf_{prog,map,btf,link}_info structs supplied to the set of LIBBPF helpers bpf_{prog,map,btf,link}_get_info_by_fd(), you can expect the helper to return an error. This can possibly leave people in a situation where they're scratching their heads for an unnnecessary amount of time. Make an explicit remark about the requirement of zero-initializing the supplied bpf_{prog,map,btf,link}_info structs for the respective LIBBPF helpers. Internally, LIBBPF helpers bpf_{prog,map,btf,link}_get_info_by_fd() call into bpf_obj_get_info_by_fd() where the bpf(2) BPF_OBJ_GET_INFO_BY_FD command is used. This specific command is effectively backed by restrictions enforced by the bpf_check_uarg_tail_zero() helper. This function ensures that if the size of the supplied bpf_{prog,map,btf,link}_info structs are larger than what the kernel can handle, trailing bits are zeroed. This can be a problem when compiling against UAPI headers that don't necessarily match the sizes of the same underlying types known to the kernel. Signed-off-by: Matt Bobrowski <mattbobrowski@google.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/bpf/ZcyEb8x4VbhieWsL@google.com
* | libbpf: Add support to GCC in CORE macro definitionsCupertino Miranda2024-02-131-7/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Due to internal differences between LLVM and GCC the current implementation for the CO-RE macros does not fit GCC parser, as it will optimize those expressions even before those would be accessible by the BPF backend. As examples, the following would be optimized out with the original definitions: - As enums are converted to their integer representation during parsing, the IR would not know how to distinguish an integer constant from an actual enum value. - Types need to be kept as temporary variables, as the existing type casts of the 0 address (as expanded for LLVM), are optimized away by the GCC C parser, never really reaching GCCs IR. Although, the macros appear to add extra complexity, the expanded code is removed from the compilation flow very early in the compilation process, not really affecting the quality of the generated assembly. Signed-off-by: Cupertino Miranda <cupertino.miranda@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240213173543.1397708-1-cupertino.miranda@oracle.com
* | libbpf: Use OPTS_SET() macro in bpf_xdp_query()Toke Høiland-Jørgensen2024-02-061-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the feature_flags and xdp_zc_max_segs fields were added to the libbpf bpf_xdp_query_opts, the code writing them did not use the OPTS_SET() macro. This causes libbpf to write to those fields unconditionally, which means that programs compiled against an older version of libbpf (with a smaller size of the bpf_xdp_query_opts struct) will have its stack corrupted by libbpf writing out of bounds. The patch adding the feature_flags field has an early bail out if the feature_flags field is not part of the opts struct (via the OPTS_HAS) macro, but the patch adding xdp_zc_max_segs does not. For consistency, this fix just changes the assignments to both fields to use the OPTS_SET() macro. Fixes: 13ce2daa259a ("xsk: add new netlink attribute dedicated for ZC max frags") Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240206125922.1992815-1-toke@redhat.com
* | libbpf: fix return value for PERF_EVENT __arg_ctx type fix up checkAndrii Nakryiko2024-02-051-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If PERF_EVENT program has __arg_ctx argument with matching architecture-specific pt_regs/user_pt_regs/user_regs_struct pointer type, libbpf should still perform type rewrite for old kernels, but not emit the warning. Fix copy/paste from kernel code where 0 is meant to signify "no error" condition. For libbpf we need to return "true" to proceed with type rewrite (which for PERF_EVENT program will be a canonical `struct bpf_perf_event_data *` type). Fixes: 9eea8fafe33e ("libbpf: fix __arg_ctx type enforcement for perf_event programs") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20240206002243.1439450-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* | libbpf: Add missed btf_ext__raw_data() APIAndrii Nakryiko2024-02-013-3/+7
| | | | | | | | | | | | | | | | | | | | | | | | Another API that was declared in libbpf.map but actual implementation was missing. btf_ext__get_raw_data() was intended as a discouraged alias to consistently-named btf_ext__raw_data(), so make this an actuality. Fixes: 20eccf29e297 ("libbpf: hide and discourage inconsistently named getters") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20240201172027.604869-5-andrii@kernel.org
* | libbpf: Add btf__new_split() API that was declared but not implementedAndrii Nakryiko2024-02-012-1/+7
| | | | | | | | | | | | | | | | | | | | | | | | Seems like original commit adding split BTF support intended to add btf__new_split() API, and even declared it in libbpf.map, but never added (trivial) implementation. Fix this. Fixes: ba451366bf44 ("libbpf: Implement basic split BTF support") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20240201172027.604869-4-andrii@kernel.org
* | libbpf: Add missing LIBBPF_API annotation to libbpf_set_memlock_rlim APIAndrii Nakryiko2024-02-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | LIBBPF_API annotation seems missing on libbpf_set_memlock_rlim API, so add it to make this API callable from libbpf's shared library version. Fixes: e542f2c4cd16 ("libbpf: Auto-bump RLIMIT_MEMLOCK if kernel needs it for BPF") Fixes: ab9a5a05dc48 ("libbpf: fix up few libbpf.map problems") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20240201172027.604869-3-andrii@kernel.org
* | libbpf: Call memfd_create() syscall directlyAndrii Nakryiko2024-02-011-1/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some versions of Android do not implement memfd_create() wrapper in their libc implementation, leading to build failures ([0]). On the other hand, memfd_create() is available as a syscall on quite old kernels (3.17+, while bpf() syscall itself is available since 3.18+), so it is ok to assume that syscall availability and call into it with syscall() helper to avoid Android-specific workarounds. Validated in libbpf-bootstrap's CI ([1]). [0] https://github.com/libbpf/libbpf-bootstrap/actions/runs/7701003207/job/20986080319#step:5:83 [1] https://github.com/libbpf/libbpf-bootstrap/actions/runs/7715988887/job/21031767212?pr=253 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20240201172027.604869-2-andrii@kernel.org
* | libbpf: Remove unnecessary null check in kernel_supports()Eduard Zingerman2024-02-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After recent changes, Coverity complained about inconsistent null checks in kernel_supports() function: kernel_supports(const struct bpf_object *obj, ...) [...] // var_compare_op: Comparing obj to null implies that obj might be null if (obj && obj->gen_loader) return true; // var_deref_op: Dereferencing null pointer obj if (obj->token_fd) return feat_supported(obj->feat_cache, feat_id); [...] - The original null check was introduced by commit [0], which introduced a call `kernel_supports(NULL, ...)` in function bump_rlimit_memlock(); - This call was refactored to use `feat_supported(NULL, ...)` in commit [1]. Looking at all places where kernel_supports() is called: - There is either `obj->...` access before the call; - Or `obj` comes from `prog->obj` expression, where `prog` comes from enumeration of programs in `obj`; - Or `obj` comes from `prog->obj`, where `prog` is a parameter to one of the API functions: - bpf_program__attach_kprobe_opts; - bpf_program__attach_kprobe; - bpf_program__attach_ksyscall. Assuming correct API usage, it appears that `obj` can never be null when passed to kernel_supports(). Silence the Coverity warning by removing redundant null check. [0] e542f2c4cd16 ("libbpf: Auto-bump RLIMIT_MEMLOCK if kernel needs it for BPF") [1] d6dd1d49367a ("libbpf: Further decouple feature checking logic from bpf_object") Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20240131212615.20112-1-eddyz87@gmail.com
* | libbpf: add bpf_core_cast() macroAndrii Nakryiko2024-01-301-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add bpf_core_cast() macro that wraps bpf_rdonly_cast() kfunc. It's more ergonomic than kfunc, as it automatically extracts btf_id with bpf_core_type_id_kernel(), and works with type names. It also casts result to (T *) pointer. See the definition of the macro, it's self-explanatory. libbpf declares bpf_rdonly_cast() extern as __weak __ksym and should be safe to not conflict with other possible declarations in user code. But we do have a conflict with current BPF selftests that declare their externs with first argument as `void *obj`, while libbpf opts into more permissive `const void *obj`. This causes conflict, so we fix up BPF selftests uses in the same patch. Acked-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20240130212023.183765-2-andrii@kernel.org Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
* | libbpf: add __arg_trusted and __arg_nullable tag macrosAndrii Nakryiko2024-01-301-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add __arg_trusted to annotate global func args that accept trusted PTR_TO_BTF_ID arguments. Also add __arg_nullable to combine with __arg_trusted (and maybe other tags in the future) to force global subprog itself (i.e., callee) to do NULL checks, as opposed to default non-NULL semantics (and thus caller's responsibility to ensure non-NULL values). Acked-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20240130000648.2144827-4-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* | libbpf: Add some details for BTF parsing failuresIan Rogers2024-01-291-4/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As CONFIG_DEBUG_INFO_BTF is default off the existing "failed to find valid kernel BTF" message makes diagnosing the kernel build issue somewhat cryptic. Add a little more detail with the hope of helping users. Before: ``` libbpf: failed to find valid kernel BTF libbpf: Error loading vmlinux BTF: -3 ``` After not accessible: ``` libbpf: kernel BTF is missing at '/sys/kernel/btf/vmlinux', was CONFIG_DEBUG_INFO_BTF enabled? libbpf: failed to find valid kernel BTF libbpf: Error loading vmlinux BTF: -3 ``` After not readable: ``` libbpf: failed to read kernel BTF from (/sys/kernel/btf/vmlinux): -1 ``` Closes: https://lore.kernel.org/bpf/CAP-5=fU+DN_+Y=Y4gtELUsJxKNDDCOvJzPHvjUVaUoeFAzNnig@mail.gmail.com/ Signed-off-by: Ian Rogers <irogers@google.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240125231840.1647951-1-irogers@google.com
* | libbpf: fix __arg_ctx type enforcement for perf_event programsAndrii Nakryiko2024-01-291-1/+20
| | | | | | | | | | | | | | | | | | | | Adjust PERF_EVENT type enforcement around __arg_ctx to match exactly what kernel is doing. Fixes: 76ec90a996e3 ("libbpf: warn on unexpected __arg_ctx type when rewriting BTF") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20240125205510.3642094-3-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* | libbpf: integrate __arg_ctx feature detector into kernel_supports()Andrii Nakryiko2024-01-293-64/+61
| | | | | | | | | | | | | | | | | | Now that feature detection code is in bpf-next tree, integrate __arg_ctx kernel-side support into kernel_supports() framework. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20240125205510.3642094-2-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* | libbpf: Fix faccessat() usage on AndroidAndrii Nakryiko2024-01-291-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Android implementation of libc errors out with -EINVAL in faccessat() if passed AT_EACCESS ([0]), this leads to ridiculous issue with libbpf refusing to load /sys/kernel/btf/vmlinux on Androids ([1]). Fix by detecting Android and redefining AT_EACCESS to 0, it's equivalent on Android. [0] https://android.googlesource.com/platform/bionic/+/refs/heads/android13-release/libc/bionic/faccessat.cpp#50 [1] https://github.com/libbpf/libbpf-bootstrap/issues/250#issuecomment-1911324250 Fixes: 6a4ab8869d0b ("libbpf: Fix the case of running as non-root with capabilities") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/bpf/20240126220944.2497665-1-andrii@kernel.org
* | libbpf: Support BPF token path setting through LIBBPF_BPF_TOKEN_PATH envvarAndrii Nakryiko2024-01-242-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | To allow external admin authority to override default BPF FS location (/sys/fs/bpf) for implicit BPF token creation, teach libbpf to recognize LIBBPF_BPF_TOKEN_PATH envvar. If it is specified and user application didn't explicitly specify bpf_token_path option, it will be treated exactly like bpf_token_path option, overriding default /sys/fs/bpf location and making BPF token mandatory. Suggested-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20240124022127.2379740-29-andrii@kernel.org
* | libbpf: Wire up BPF token support at BPF object levelAndrii Nakryiko2024-01-244-11/+131
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add BPF token support to BPF object-level functionality. BPF token is supported by BPF object logic either as an explicitly provided BPF token from outside (through BPF FS path), or implicitly (unless prevented through bpf_object_open_opts). Implicit mode is assumed to be the most common one for user namespaced unprivileged workloads. The assumption is that privileged container manager sets up default BPF FS mount point at /sys/fs/bpf with BPF token delegation options (delegate_{cmds,maps,progs,attachs} mount options). BPF object during loading will attempt to create BPF token from /sys/fs/bpf location, and pass it for all relevant operations (currently, map creation, BTF load, and program load). In this implicit mode, if BPF token creation fails due to whatever reason (BPF FS is not mounted, or kernel doesn't support BPF token, etc), this is not considered an error. BPF object loading sequence will proceed with no BPF token. In explicit BPF token mode, user provides explicitly custom BPF FS mount point path. In such case, BPF object will attempt to create BPF token from provided BPF FS location. If BPF token creation fails, that is considered a critical error and BPF object load fails with an error. Libbpf provides a way to disable implicit BPF token creation, if it causes any troubles (BPF token is designed to be completely optional and shouldn't cause any problems even if provided, but in the world of BPF LSM, custom security logic can be installed that might change outcome depending on the presence of BPF token). To disable libbpf's default BPF token creation behavior user should provide either invalid BPF token FD (negative), or empty bpf_token_path option. BPF token presence can influence libbpf's feature probing, so if BPF object has associated BPF token, feature probing is instructed to use BPF object-specific feature detection cache and token FD. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20240124022127.2379740-26-andrii@kernel.org
* | libbpf: Wire up token_fd into feature probing logicAndrii Nakryiko2024-01-245-47/+97
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adjust feature probing callbacks to take into account optional token_fd. In unprivileged contexts, some feature detectors would fail to detect kernel support just because BPF program, BPF map, or BTF object can't be loaded due to privileged nature of those operations. So when BPF object is loaded with BPF token, this token should be used for feature probing. This patch is setting support for this scenario, but we don't yet pass non-zero token FD. This will be added in the next patch. We also switched BPF cookie detector from using kprobe program to tracepoint one, as tracepoint is somewhat less dangerous BPF program type and has higher likelihood of being allowed through BPF token in the future. This change has no effect on detection behavior. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20240124022127.2379740-25-andrii@kernel.org
* | libbpf: Move feature detection code into its own fileAndrii Nakryiko2024-01-246-466/+481
| | | | | | | | | | | | | | | | | | | | It's quite a lot of well isolated code, so it seems like a good candidate to move it out of libbpf.c to reduce its size. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20240124022127.2379740-24-andrii@kernel.org
* | libbpf: Further decouple feature checking logic from bpf_objectAndrii Nakryiko2024-01-243-11/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | Add feat_supported() helper that accepts feature cache instead of bpf_object. This allows low-level code in bpf.c to not know or care about higher-level concept of bpf_object, yet it will be able to utilize custom feature checking in cases where BPF token might influence the outcome. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20240124022127.2379740-23-andrii@kernel.org
* | libbpf: Split feature detectors definitions from cached resultsAndrii Nakryiko2024-01-241-6/+12
| | | | | | | | | | | | | | | | | | | | | | | | Split a list of supported feature detectors with their corresponding callbacks from actual cached supported/missing values. This will allow to have more flexible per-token or per-object feature detectors in subsequent refactorings. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20240124022127.2379740-22-andrii@kernel.org
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-25 05:08:09 +0000