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2026-03-04bpftool: Fix truncated netlink dumpsJakub Kicinski1-1/+3
[ Upstream commit 3b39d73cc3379360a33eb583b17f21fe55e1288e ] Netlink requires that the recv buffer used during dumps is at least min(PAGE_SIZE, 8k) (see the man page). Otherwise the messages will get truncated. Make sure bpftool follows this requirement, avoid missing information on systems with large pages. Acked-by: Quentin Monnet <qmo@kernel.org> Fixes: 7084566a236f ("tools/bpftool: Remove libbpf_internal.h usage in bpftool") Signed-off-by: Jakub Kicinski <kuba@kernel.org> Link: https://lore.kernel.org/r/20260217194150.734701-1-kuba@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04libbpf: Fix OOB read in btf_dump_get_bitfield_valueVarun R Mallya1-0/+9
[ Upstream commit 5714ca8cba5ed736f3733663c446cbee63a10a64 ] When dumping bitfield data, btf_dump_get_bitfield_value() reads data based on the underlying type's size (t->size). However, it does not verify that the provided data buffer (data_sz) is large enough to contain these bytes. If btf_dump__dump_type_data() is called with a buffer smaller than the type's size, this leads to an out-of-bounds read. This was confirmed by AddressSanitizer in the linked issue. Fix this by ensuring we do not read past the provided data_sz limit. Fixes: a1d3cc3c5eca ("libbpf: Avoid use of __int128 in typed dump display") Reported-by: Harrison Green <harrisonmichaelgreen@gmail.com> Suggested-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Varun R Mallya <varunrmallya@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20260106233527.163487-1-varunrmallya@gmail.com Closes: https://github.com/libbpf/libbpf/issues/928 Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-07libbpf: Fix powerpc's stack register definition in bpf_tracing.hAndrii Nakryiko1-1/+1
[ Upstream commit 7221b9caf84b3294688228a19273d74ea19a2ee4 ] retsnoop's build on powerpc (ppc64le) architecture ([0]) failed due to wrong definition of PT_REGS_SP() macro. Looking at powerpc's implementation of stack unwinding in perf_callchain_user_64() clearly shows that stack pointer register is gpr[1]. Fix libbpf's definition of __PT_SP_REG for powerpc to fix all this. [0] https://kojipkgs.fedoraproject.org/work/tasks/1544/137921544/build.log Fixes: 138d6153a139 ("samples/bpf: Enable powerpc support") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Naveen N Rao (AMD) <naveen@kernel.org> Link: https://lore.kernel.org/r/20251020203643.989467-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-10-15libbpf: Fix reuse of DEVMAPYureka Lilian1-0/+10
[ Upstream commit 6c6b4146deb12d20f42490d5013f2043df942161 ] Previously, re-using pinned DEVMAP maps would always fail, because get_map_info on a DEVMAP always returns flags with BPF_F_RDONLY_PROG set, but BPF_F_RDONLY_PROG being set on a map during creation is invalid. Thus, ignore the BPF_F_RDONLY_PROG flag in the flags returned from get_map_info when checking for compatibility with an existing DEVMAP. The same problem is handled in a third-party ebpf library: - https://github.com/cilium/ebpf/issues/925 - https://github.com/cilium/ebpf/pull/930 Fixes: 0cdbb4b09a06 ("devmap: Allow map lookups from eBPF") Signed-off-by: Yureka Lilian <yuka@yuka.dev> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250814180113.1245565-3-yuka@yuka.dev Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-06libbpf: Fix null pointer dereference in btf_dump__free on allocation failureYuan Chen1-0/+3
[ Upstream commit aa485e8789d56a4573f7c8d000a182b749eaa64d ] When btf_dump__new() fails to allocate memory for the internal hashmap (btf_dump->type_names), it returns an error code. However, the cleanup function btf_dump__free() does not check if btf_dump->type_names is NULL before attempting to free it. This leads to a null pointer dereference when btf_dump__free() is called on a btf_dump object. Fixes: 351131b51c7a ("libbpf: add btf_dump API for BTF-to-C conversion") Signed-off-by: Yuan Chen <chenyuan@kylinos.cn> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250618011933.11423-1-chenyuan_fl@163.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-27libbpf: Add identical pointer detection to btf_dedup_is_equiv()Alan Maguire1-0/+16
[ Upstream commit 8e64c387c942229c551d0f23de4d9993d3a2acb6 ] Recently as a side-effect of commit ac053946f5c4 ("compiler.h: introduce TYPEOF_UNQUAL() macro") issues were observed in deduplication between modules and kernel BTF such that a large number of kernel types were not deduplicated so were found in module BTF (task_struct, bpf_prog etc). The root cause appeared to be a failure to dedup struct types, specifically those with members that were pointers with __percpu annotations. The issue in dedup is at the point that we are deduplicating structures, we have not yet deduplicated reference types like pointers. If multiple copies of a pointer point at the same (deduplicated) integer as in this case, we do not see them as identical. Special handling already exists to deal with structures and arrays, so add pointer handling here too. Reported-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250429161042.2069678-1-alan.maguire@oracle.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-27libbpf: Use proper errno value in nlattrAnton Protopopov1-8/+7
[ Upstream commit fd5fd538a1f4b34cee6823ba0ddda2f7a55aca96 ] Return value of the validate_nla() function can be propagated all the way up to users of libbpf API. In case of error this libbpf version of validate_nla returns -1 which will be seen as -EPERM from user's point of view. Instead, return a more reasonable -EINVAL. Fixes: bbf48c18ee0c ("libbpf: add error reporting in XDP") Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250510182011.2246631-1-a.s.protopopov@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-27bpf: Fix uninitialized values in BPF_{CORE,PROBE}_READAnton Protopopov1-0/+6
[ Upstream commit 41d4ce6df3f4945341ec509a840cc002a413b6cc ] With the latest LLVM bpf selftests build will fail with the following error message: progs/profiler.inc.h:710:31: error: default initialization of an object of type 'typeof ((parent_task)->real_cred->uid.val)' (aka 'const unsigned int') leaves the object uninitialized and is incompatible with C++ [-Werror,-Wdefault-const-init-unsafe] 710 | proc_exec_data->parent_uid = BPF_CORE_READ(parent_task, real_cred, uid.val); | ^ tools/testing/selftests/bpf/tools/include/bpf/bpf_core_read.h:520:35: note: expanded from macro 'BPF_CORE_READ' 520 | ___type((src), a, ##__VA_ARGS__) __r; \ | ^ This happens because BPF_CORE_READ (and other macro) declare the variable __r using the ___type macro which can inherit const modifier from intermediate types. Fix this by using __typeof_unqual__, when supported. (And when it is not supported, the problem shouldn't appear, as older compilers haven't complained.) Fixes: 792001f4f7aa ("libbpf: Add user-space variants of BPF_CORE_READ() family of macros") Fixes: a4b09a9ef945 ("libbpf: Add non-CO-RE variants of BPF_CORE_READ() macro family") Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250502193031.3522715-1-a.s.protopopov@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-27libbpf: Use proper errno value in linkerAnton Protopopov1-2/+2
[ Upstream commit 358b1c0f56ebb6996fcec7dcdcf6bae5dcbc8b6c ] Return values of the linker_append_sec_data() and the linker_append_elf_relos() functions are propagated all the way up to users of libbpf API. In some error cases these functions return -1 which will be seen as -EPERM from user's point of view. Instead, return a more reasonable -EINVAL. Fixes: faf6ed321cf6 ("libbpf: Add BPF static linker APIs") Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250430120820.2262053-1-a.s.protopopov@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-27libbpf: Fix buffer overflow in bpf_object__init_progViktor Malik1-1/+1
[ Upstream commit ee684de5c1b0ac01821320826baec7da93f3615b ] As shown in [1], it is possible to corrupt a BPF ELF file such that arbitrary BPF instructions are loaded by libbpf. This can be done by setting a symbol (BPF program) section offset to a large (unsigned) number such that <section start + symbol offset> overflows and points before the section data in the memory. Consider the situation below where: - prog_start = sec_start + symbol_offset <-- size_t overflow here - prog_end = prog_start + prog_size prog_start sec_start prog_end sec_end | | | | v v v v .....................|################################|............ The report in [1] also provides a corrupted BPF ELF which can be used as a reproducer: $ readelf -S crash Section Headers: [Nr] Name Type Address Offset Size EntSize Flags Link Info Align ... [ 2] uretprobe.mu[...] PROGBITS 0000000000000000 00000040 0000000000000068 0000000000000000 AX 0 0 8 $ readelf -s crash Symbol table '.symtab' contains 8 entries: Num: Value Size Type Bind Vis Ndx Name ... 6: ffffffffffffffb8 104 FUNC GLOBAL DEFAULT 2 handle_tp Here, the handle_tp prog has section offset ffffffffffffffb8, i.e. will point before the actual memory where section 2 is allocated. This is also reported by AddressSanitizer: ================================================================= ==1232==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7c7302fe0000 at pc 0x7fc3046e4b77 bp 0x7ffe64677cd0 sp 0x7ffe64677490 READ of size 104 at 0x7c7302fe0000 thread T0 #0 0x7fc3046e4b76 in memcpy (/lib64/libasan.so.8+0xe4b76) #1 0x00000040df3e in bpf_object__init_prog /src/libbpf/src/libbpf.c:856 #2 0x00000040df3e in bpf_object__add_programs /src/libbpf/src/libbpf.c:928 #3 0x00000040df3e in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3930 #4 0x00000040df3e in bpf_object_open /src/libbpf/src/libbpf.c:8067 #5 0x00000040f176 in bpf_object__open_file /src/libbpf/src/libbpf.c:8090 #6 0x000000400c16 in main /poc/poc.c:8 #7 0x7fc3043d25b4 in __libc_start_call_main (/lib64/libc.so.6+0x35b4) #8 0x7fc3043d2667 in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x3667) #9 0x000000400b34 in _start (/poc/poc+0x400b34) 0x7c7302fe0000 is located 64 bytes before 104-byte region [0x7c7302fe0040,0x7c7302fe00a8) allocated by thread T0 here: #0 0x7fc3046e716b in malloc (/lib64/libasan.so.8+0xe716b) #1 0x7fc3045ee600 in __libelf_set_rawdata_wrlock (/lib64/libelf.so.1+0xb600) #2 0x7fc3045ef018 in __elf_getdata_rdlock (/lib64/libelf.so.1+0xc018) #3 0x00000040642f in elf_sec_data /src/libbpf/src/libbpf.c:3740 The problem here is that currently, libbpf only checks that the program end is within the section bounds. There used to be a check `while (sec_off < sec_sz)` in bpf_object__add_programs, however, it was removed by commit 6245947c1b3c ("libbpf: Allow gaps in BPF program sections to support overriden weak functions"). Add a check for detecting the overflow of `sec_off + prog_sz` to bpf_object__init_prog to fix this issue. [1] https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md Fixes: 6245947c1b3c ("libbpf: Allow gaps in BPF program sections to support overriden weak functions") Reported-by: lmarch2 <2524158037@qq.com> Signed-off-by: Viktor Malik <vmalik@redhat.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Shung-Hsi Yu <shung-hsi.yu@suse.com> Link: https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md Link: https://lore.kernel.org/bpf/20250415155014.397603-1-vmalik@redhat.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-04libbpf: Fix out-of-bound readNandakumar Edamana1-1/+1
[ Upstream commit 236d3910117e9f97ebf75e511d8bcc950f1a4e5f ] In `set_kcfg_value_str`, an untrusted string is accessed with the assumption that it will be at least two characters long due to the presence of checks for opening and closing quotes. But the check for the closing quote (value[len - 1] != '"') misses the fact that it could be checking the opening quote itself in case of an invalid input that consists of just the opening quote. This commit adds an explicit check to make sure the string is at least two characters long. Signed-off-by: Nandakumar Edamana <nandakumar@nandakumar.co.in> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250221210110.3182084-1-nandakumar@nandakumar.co.in Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10libbpf: Fix hypothetical STT_SECTION extern NULL deref caseAndrii Nakryiko1-1/+1
[ Upstream commit e0525cd72b5979d8089fe524a071ea93fd011dc9 ] Fix theoretical NULL dereference in linker when resolving *extern* STT_SECTION symbol against not-yet-existing ELF section. Not sure if it's possible in practice for valid ELF object files (this would require embedded assembly manipulations, at which point BTF will be missing), but fix the s/dst_sym/dst_sec/ typo guarding this condition anyways. Fixes: faf6ed321cf6 ("libbpf: Add BPF static linker APIs") Fixes: a46349227cd8 ("libbpf: Add linker extern resolution support for functions and global variables") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20250220002821.834400-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-21libbpf: Fix segfault due to libelf functions not setting errnoQuentin Monnet1-14/+8
[ Upstream commit e10500b69c3f3378f3dcfc8c2fe4cdb74fc844f5 ] Libelf functions do not set errno on failure. Instead, it relies on its internal _elf_errno value, that can be retrieved via elf_errno (or the corresponding message via elf_errmsg()). From "man libelf": If a libelf function encounters an error it will set an internal error code that can be retrieved with elf_errno. Each thread maintains its own separate error code. The meaning of each error code can be determined with elf_errmsg, which returns a string describing the error. As a consequence, libbpf should not return -errno when a function from libelf fails, because an empty value will not be interpreted as an error and won't prevent the program to stop. This is visible in bpf_linker__add_file(), for example, where we call a succession of functions that rely on libelf: err = err ?: linker_load_obj_file(linker, filename, opts, &obj); err = err ?: linker_append_sec_data(linker, &obj); err = err ?: linker_append_elf_syms(linker, &obj); err = err ?: linker_append_elf_relos(linker, &obj); err = err ?: linker_append_btf(linker, &obj); err = err ?: linker_append_btf_ext(linker, &obj); If the object file that we try to process is not, in fact, a correct object file, linker_load_obj_file() may fail with errno not being set, and return 0. In this case we attempt to run linker_append_elf_sysms() and may segfault. This can happen (and was discovered) with bpftool: $ bpftool gen object output.o sample_ret0.bpf.c libbpf: failed to get ELF header for sample_ret0.bpf.c: invalid `Elf' handle zsh: segmentation fault (core dumped) bpftool gen object output.o sample_ret0.bpf.c Fix the issue by returning a non-null error code (-EINVAL) when libelf functions fail. Fixes: faf6ed321cf6 ("libbpf: Add BPF static linker APIs") Signed-off-by: Quentin Monnet <qmo@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20241205135942.65262-1-qmo@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-21libbpf: don't adjust USDT semaphore address if .stapsdt.base addr is missingAndrii Nakryiko1-1/+1
[ Upstream commit 98ebe5ef6f5c4517ba92fb3e56f95827ebea83fd ] USDT ELF note optionally can record an offset of .stapsdt.base, which is used to make adjustments to USDT target attach address. Currently, libbpf will do this address adjustment unconditionally if it finds .stapsdt.base ELF section in target binary. But there is a corner case where .stapsdt.base ELF section is present, but specific USDT note doesn't reference it. In such case, libbpf will basically just add base address and end up with absolutely incorrect USDT target address. This adjustment has to be done only if both .stapsdt.sema section is present and USDT note is recording a reference to it. Fixes: 74cc6311cec9 ("libbpf: Add USDT notes parsing and resolution logic") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20241121224558.796110-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-14libbpf: never interpret subprogs in .text as entry programsAndrii Nakryiko1-1/+1
[ Upstream commit db089c9158c1d535a36dfc010e5db37fccea2561 ] Libbpf pre-1.0 had a legacy logic of allowing singular non-annotated (i.e., not having explicit SEC() annotation) function to be treated as sole entry BPF program (unless there were other explicit entry programs). This behavior was dropped during libbpf 1.0 transition period (unless LIBBPF_STRICT_SEC_NAME flag was unset in libbpf_mode). When 1.0 was released and all the legacy behavior was removed, the bug slipped through leaving this legacy behavior around. Fix this for good, as it actually causes very confusing behavior if BPF object file only has subprograms, but no entry programs. Fixes: bd054102a8c7 ("libbpf: enforce strict libbpf 1.0 behaviors") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20241010211731.4121837-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-14libbpf: fix sym_is_subprog() logic for weak global subprogsAndrii Nakryiko1-1/+1
[ Upstream commit 4073213488be542f563eb4b2457ab4cbcfc2b738 ] sym_is_subprog() is incorrectly rejecting relocations against *weak* global subprogs. Fix that by realizing that STB_WEAK is also a global function. While it seems like verifier doesn't support taking an address of non-static subprog right now, it's still best to fix support for it on libbpf side, otherwise users will get a very confusing error during BPF skeleton generation or static linking due to misinterpreted relocation: libbpf: prog 'handle_tp': bad map relo against 'foo' in section '.text' Error: failed to open BPF object file: Relocation failed It's clearly not a map relocation, but is treated and reported as such without this fix. Fixes: 53eddb5e04ac ("libbpf: Support subprog address relocation") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20241009011554.880168-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-14libbpf: Fix output .symtab byte-order during linkingTony Ambardar1-0/+2
[ Upstream commit f896b4a5399e97af0b451fcf04754ed316935674 ] Object linking output data uses the default ELF_T_BYTE type for '.symtab' section data, which disables any libelf-based translation. Explicitly set the ELF_T_SYM type for output to restore libelf's byte-order conversion, noting that input '.symtab' data is already correctly translated. Fixes: faf6ed321cf6 ("libbpf: Add BPF static linker APIs") Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/87868bfeccf3f51aec61260073f8778e9077050a.1726475448.git.tony.ambardar@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-09-12libbpf: Add NULL checks to bpf_object__{prev_map,next_map}Andreas Ziegler1-2/+2
[ Upstream commit cedc12c5b57f7efa6dbebfb2b140e8675f5a2616 ] In the current state, an erroneous call to bpf_object__find_map_by_name(NULL, ...) leads to a segmentation fault through the following call chain: bpf_object__find_map_by_name(obj = NULL, ...) -> bpf_object__for_each_map(pos, obj = NULL) -> bpf_object__next_map((obj = NULL), NULL) -> return (obj = NULL)->maps While calling bpf_object__find_map_by_name with obj = NULL is obviously incorrect, this should not lead to a segmentation fault but rather be handled gracefully. As __bpf_map__iter already handles this situation correctly, we can delegate the check for the regular case there and only add a check in case the prev or next parameter is NULL. Signed-off-by: Andreas Ziegler <ziegler.andreas@siemens.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20240703083436.505124-1-ziegler.andreas@siemens.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-03libbpf: Fix no-args func prototype BTF dumping syntaxAndrii Nakryiko1-3/+5
[ Upstream commit 189f1a976e426011e6a5588f1d3ceedf71fe2965 ] For all these years libbpf's BTF dumper has been emitting not strictly valid syntax for function prototypes that have no input arguments. Instead of `int (*blah)()` we should emit `int (*blah)(void)`. This is not normally a problem, but it manifests when we get kfuncs in vmlinux.h that have no input arguments. Due to compiler internal specifics, we get no BTF information for such kfuncs, if they are not declared with proper `(void)`. The fix is trivial. We also need to adjust a few ancient tests that happily assumed `()` is correct. Fixes: 351131b51c7a ("libbpf: add btf_dump API for BTF-to-C conversion") Reported-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://lore.kernel.org/bpf/20240712224442.282823-1-andrii@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-03libbpf: Checking the btf_type kind when fixing variable offsetsDonglin Peng1-2/+9
[ Upstream commit cc5083d1f3881624ad2de1f3cbb3a07e152cb254 ] I encountered an issue when building the test_progs from the repository [1]: $ pwd /work/Qemu/x86_64/linux-6.10-rc2/tools/testing/selftests/bpf/ $ make test_progs V=1 [...] ./tools/sbin/bpftool gen object ./ip_check_defrag.bpf.linked2.o ./ip_check_defrag.bpf.linked1.o libbpf: failed to find symbol for variable 'bpf_dynptr_slice' in section '.ksyms' Error: failed to link './ip_check_defrag.bpf.linked1.o': No such file or directory (2) [...] Upon investigation, I discovered that the btf_types referenced in the '.ksyms' section had a kind of BTF_KIND_FUNC instead of BTF_KIND_VAR: $ bpftool btf dump file ./ip_check_defrag.bpf.linked1.o [...] [2] DATASEC '.ksyms' size=0 vlen=2 type_id=16 offset=0 size=0 (FUNC 'bpf_dynptr_from_skb') type_id=17 offset=0 size=0 (FUNC 'bpf_dynptr_slice') [...] [16] FUNC 'bpf_dynptr_from_skb' type_id=82 linkage=extern [17] FUNC 'bpf_dynptr_slice' type_id=85 linkage=extern [...] For a detailed analysis, please refer to [2]. We can add a kind checking to fix the issue. [1] https://github.com/eddyz87/bpf/tree/binsort-btf-dedup [2] https://lore.kernel.org/all/0c0ef20c-c05e-4db9-bad7-2cbc0d6dfae7@oracle.com/ Fixes: 8fd27bf69b86 ("libbpf: Add BPF static linker BTF and BTF.ext support") Signed-off-by: Donglin Peng <dolinux.peng@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20240619122355.426405-1-dolinux.peng@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-11bpf: Avoid uninitialized value in BPF_CORE_READ_BITFIELDJose E. Marchesi1-0/+1
[ Upstream commit 009367099eb61a4fc2af44d4eb06b6b4de7de6db ] [Changes from V1: - Use a default branch in the switch statement to initialize `val'.] GCC warns that `val' may be used uninitialized in the BPF_CRE_READ_BITFIELD macro, defined in bpf_core_read.h as: [...] unsigned long long val; \ [...] \ switch (__CORE_RELO(s, field, BYTE_SIZE)) { \ case 1: val = *(const unsigned char *)p; break; \ case 2: val = *(const unsigned short *)p; break; \ case 4: val = *(const unsigned int *)p; break; \ case 8: val = *(const unsigned long long *)p; break; \ } \ [...] val; \ } \ This patch adds a default entry in the switch statement that sets `val' to zero in order to avoid the warning, and random values to be used in case __builtin_preserve_field_info returns unexpected values for BPF_FIELD_BYTE_SIZE. Tested in bpf-next master. No regressions. Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240508101313.16662-1-jose.marchesi@oracle.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-12libbpf: Fix error message in attach_kprobe_multiJiri Olsa1-1/+1
[ Upstream commit 7c13ef16e87ac2e44d16c0468b1191bceb06f95c ] We just failed to retrieve pattern, so we need to print spec instead. Fixes: ddc6b04989eb ("libbpf: Add bpf_program__attach_kprobe_multi_opts function") Reported-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240502075541.1425761-2-jolsa@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-27libbpf: Add missing LIBBPF_API annotation to libbpf_set_memlock_rlim APIAndrii Nakryiko1-1/+1
[ Upstream commit 93ee1eb85e28d1e35bb059c1f5965d65d5fc83c2 ] 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 Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-27libbpf: Fix faccessat() usage on AndroidAndrii Nakryiko1-0/+14
[ Upstream commit ad57654053805bf9a62602aaec74cc78edb6f235 ] 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 Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-27libbpf: Apply map_set_def_max_entries() for inner_maps on creationAndrey Grafin1-0/+4
[ Upstream commit f04deb90e516e8e48bf8693397529bc942a9e80b ] This patch allows to auto create BPF_MAP_TYPE_ARRAY_OF_MAPS and BPF_MAP_TYPE_HASH_OF_MAPS with values of BPF_MAP_TYPE_PERF_EVENT_ARRAY by bpf_object__load(). Previous behaviour created a zero filled btf_map_def for inner maps and tried to use it for a map creation but the linux kernel forbids to create a BPF_MAP_TYPE_PERF_EVENT_ARRAY map with max_entries=0. Fixes: 646f02ffdd49 ("libbpf: Add BTF-defined map-in-map support") Signed-off-by: Andrey Grafin <conquistador@yandex-team.ru> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yonghong.song@linux.dev> Acked-by: Hou Tao <houtao1@huawei.com> Link: https://lore.kernel.org/bpf/20240117130619.9403-1-conquistador@yandex-team.ru Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-02-05libbpf: Fix NULL pointer dereference in bpf_object__collect_prog_relosMingyi Zhang1-0/+2
[ Upstream commit fc3a5534e2a8855427403113cbeb54af5837bbe0 ] An issue occurred while reading an ELF file in libbpf.c during fuzzing: Program received signal SIGSEGV, Segmentation fault. 0x0000000000958e97 in bpf_object.collect_prog_relos () at libbpf.c:4206 4206 in libbpf.c (gdb) bt #0 0x0000000000958e97 in bpf_object.collect_prog_relos () at libbpf.c:4206 #1 0x000000000094f9d6 in bpf_object.collect_relos () at libbpf.c:6706 #2 0x000000000092bef3 in bpf_object_open () at libbpf.c:7437 #3 0x000000000092c046 in bpf_object.open_mem () at libbpf.c:7497 #4 0x0000000000924afa in LLVMFuzzerTestOneInput () at fuzz/bpf-object-fuzzer.c:16 #5 0x000000000060be11 in testblitz_engine::fuzzer::Fuzzer::run_one () #6 0x000000000087ad92 in tracing::span::Span::in_scope () #7 0x00000000006078aa in testblitz_engine::fuzzer::util::walkdir () #8 0x00000000005f3217 in testblitz_engine::entrypoint::main::{{closure}} () #9 0x00000000005f2601 in main () (gdb) scn_data was null at this code(tools/lib/bpf/src/libbpf.c): if (rel->r_offset % BPF_INSN_SZ || rel->r_offset >= scn_data->d_size) { The scn_data is derived from the code above: scn = elf_sec_by_idx(obj, sec_idx); scn_data = elf_sec_data(obj, scn); relo_sec_name = elf_sec_str(obj, shdr->sh_name); sec_name = elf_sec_name(obj, scn); if (!relo_sec_name || !sec_name)// don't check whether scn_data is NULL return -EINVAL; In certain special scenarios, such as reading a malformed ELF file, it is possible that scn_data may be a null pointer Signed-off-by: Mingyi Zhang <zhangmingyi5@huawei.com> Signed-off-by: Xin Liu <liuxin350@huawei.com> Signed-off-by: Changye Wu <wuchangye@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20231221033947.154564-1-liuxin350@huawei.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-09-23libbpf: Free btf_vmlinux when closing bpf_objectHao Luo1-0/+1
[ Upstream commit 29d67fdebc42af6466d1909c60fdd1ef4f3e5240 ] I hit a memory leak when testing bpf_program__set_attach_target(). Basically, set_attach_target() may allocate btf_vmlinux, for example, when setting attach target for bpf_iter programs. But btf_vmlinux is freed only in bpf_object_load(), which means if we only open bpf object but not load it, setting attach target may leak btf_vmlinux. So let's free btf_vmlinux in bpf_object__close() anyway. Signed-off-by: Hao Luo <haoluo@google.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230822193840.1509809-1-haoluo@google.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-09-13libbpf: Fix realloc API handling in zero-sized edge casesAndrii Nakryiko2-4/+16
[ Upstream commit 8a0260dbf6553c969248b6530cafadac46562f47 ] realloc() and reallocarray() can either return NULL or a special non-NULL pointer, if their size argument is zero. This requires a bit more care to handle NULL-as-valid-result situation differently from NULL-as-error case. This has caused real issues before ([0]), and just recently bit again in production when performing bpf_program__attach_usdt(). This patch fixes 4 places that do or potentially could suffer from this mishandling of NULL, including the reported USDT-related one. There are many other places where realloc()/reallocarray() is used and NULL is always treated as an error value, but all those have guarantees that their size is always non-zero, so those spot don't need any extra handling. [0] d08ab82f59d5 ("libbpf: Fix double-free when linker processes empty sections") Fixes: 999783c8bbda ("libbpf: Wire up spec management and other arch-independent USDT logic") Fixes: b63b3c490eee ("libbpf: Add bpf_program__set_insns function") Fixes: 697f104db8a6 ("libbpf: Support custom SEC() handlers") Fixes: b12688267280 ("libbpf: Change the order of data and text relocations.") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230711024150.1566433-1-andrii@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19libbpf: fix offsetof() and container_of() to work with CO-REAndrii Nakryiko1-5/+10
[ Upstream commit bdeeed3498c7871c17465bb4f11d1bc67f9098af ] It seems like __builtin_offset() doesn't preserve CO-RE field relocations properly. So if offsetof() macro is defined through __builtin_offset(), CO-RE-enabled BPF code using container_of() will be subtly and silently broken. To avoid this problem, redefine offsetof() and container_of() in the form that works with CO-RE relocations more reliably. Fixes: 5fbc220862fc ("tools/libpf: Add offsetof/container_of macro in bpf_helpers.h") Reported-by: Lennart Poettering <lennart@poettering.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20230509065502.2306180-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19libbpf: btf_dump_type_data_check_overflow needs to consider ↵Martin KaFai Lau1-3/+19
BTF_MEMBER_BITFIELD_SIZE [ Upstream commit c39028b333f3a3a765c5c0b9726b8e38aedf0ba1 ] The btf_dump/struct_data selftest is failing with: [...] test_btf_dump_struct_data:FAIL:unexpected return value dumping fs_context unexpected unexpected return value dumping fs_context: actual -7 != expected 264 [...] The reason is in btf_dump_type_data_check_overflow(). It does not use BTF_MEMBER_BITFIELD_SIZE from the struct's member (btf_member). Instead, it is using the enum size which is 4. It had been working till the recent commit 4e04143c869c ("fs_context: drop the unused lsm_flags member") removed an integer member which also removed the 4 bytes padding at the end of the fs_context. Missing this 4 bytes padding exposed this bug. In particular, when btf_dump_type_data_check_overflow() reaches the member 'phase', -E2BIG is returned. The fix is to pass bit_sz to btf_dump_type_data_check_overflow(). In btf_dump_type_data_check_overflow(), it does a different size check when bit_sz is not zero. The current fs_context: [3600] ENUM 'fs_context_purpose' encoding=UNSIGNED size=4 vlen=3 'FS_CONTEXT_FOR_MOUNT' val=0 'FS_CONTEXT_FOR_SUBMOUNT' val=1 'FS_CONTEXT_FOR_RECONFIGURE' val=2 [3601] ENUM 'fs_context_phase' encoding=UNSIGNED size=4 vlen=7 'FS_CONTEXT_CREATE_PARAMS' val=0 'FS_CONTEXT_CREATING' val=1 'FS_CONTEXT_AWAITING_MOUNT' val=2 'FS_CONTEXT_AWAITING_RECONF' val=3 'FS_CONTEXT_RECONF_PARAMS' val=4 'FS_CONTEXT_RECONFIGURING' val=5 'FS_CONTEXT_FAILED' val=6 [3602] STRUCT 'fs_context' size=264 vlen=21 'ops' type_id=3603 bits_offset=0 'uapi_mutex' type_id=235 bits_offset=64 'fs_type' type_id=872 bits_offset=1216 'fs_private' type_id=21 bits_offset=1280 'sget_key' type_id=21 bits_offset=1344 'root' type_id=781 bits_offset=1408 'user_ns' type_id=251 bits_offset=1472 'net_ns' type_id=984 bits_offset=1536 'cred' type_id=1785 bits_offset=1600 'log' type_id=3621 bits_offset=1664 'source' type_id=42 bits_offset=1792 'security' type_id=21 bits_offset=1856 's_fs_info' type_id=21 bits_offset=1920 'sb_flags' type_id=20 bits_offset=1984 'sb_flags_mask' type_id=20 bits_offset=2016 's_iflags' type_id=20 bits_offset=2048 'purpose' type_id=3600 bits_offset=2080 bitfield_size=8 'phase' type_id=3601 bits_offset=2088 bitfield_size=8 'need_free' type_id=67 bits_offset=2096 bitfield_size=1 'global' type_id=67 bits_offset=2097 bitfield_size=1 'oldapi' type_id=67 bits_offset=2098 bitfield_size=1 Fixes: 920d16af9b42 ("libbpf: BTF dumper support for typed data") Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20230428013638.1581263-1-martin.lau@linux.dev Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-05-11libbpf: Fix ld_imm64 copy logic for ksym in light skeleton.Alexei Starovoitov1-4/+6
[ Upstream commit a506d6ce1dd184051037dc9d26c3eb187c9fe625 ] Unlike normal libbpf the light skeleton 'loader' program is doing btf_find_by_name_kind() call at run-time to find ksym in the kernel and populate its {btf_id, btf_obj_fd} pair in ld_imm64 insn. To avoid doing the search multiple times for the same ksym it remembers the first patched ld_imm64 insn and copies {btf_id, btf_obj_fd} from it into subsequent ld_imm64 insn. Fix a bug in copying logic, since it may incorrectly clear BPF_PSEUDO_BTF_ID flag. Also replace always true if (btf_obj_fd >= 0) check with unconditional JMP_JA to clarify the code. Fixes: d995816b77eb ("libbpf: Avoid reload of imm for weak, unresolved, repeating ksym") Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230319203014.55866-1-alexei.starovoitov@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-20libbpf: Fix single-line struct definition output in btf_dumpAndrii Nakryiko1-2/+5
[ Upstream commit 872aec4b5f635d94111d48ec3c57fbe078d64e7d ] btf_dump APIs emit unnecessary tabs when emitting struct/union definition that fits on the single line. Before this patch we'd get: struct blah {<tab>}; This patch fixes this and makes sure that we get more natural: struct blah {}; Fixes: 44a726c3f23c ("bpftool: Print newline before '}' for struct with padding only fields") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20221212211505.558851-2-andrii@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-13bpftool: Print newline before '}' for struct with padding only fieldsEduard Zingerman1-1/+5
[ Upstream commit 44a726c3f23cf762ef4ce3c1709aefbcbe97f62c ] 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 Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-06libbpf: Fix btf_dump's packed struct determinationAndrii Nakryiko1-27/+6
[ Upstream commit 4fb877aaa179dcdb1676d55216482febaada457e ] Fix bug in btf_dump's logic of determining if a given struct type is packed or not. The notion of "natural alignment" is not needed and is even harmful in this case, so drop it altogether. The biggest difference in btf_is_struct_packed() compared to its original implementation is that we don't really use btf__align_of() to determine overall alignment of a struct type (because it could be 1 for both packed and non-packed struct, depending on specifci field definitions), and just use field's actual alignment to calculate whether any field is requiring packing or struct's size overall necessitates packing. Add two simple test cases that demonstrate the difference this change would make. Fixes: ea2ce1ba99aa ("libbpf: Fix BTF-to-C converter's padding logic") Reported-by: Eduard Zingerman <eddyz87@gmail.com> 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/20221215183605.4149488-1-andrii@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-06libbpf: Fix BTF-to-C converter's padding logicAndrii Nakryiko1-46/+123
[ Upstream commit ea2ce1ba99aa6a60c8d8a706e3abadf3de372163 ] Turns out that btf_dump API doesn't handle a bunch of tricky corner cases, as reported by Per, and further discovered using his testing Python script ([0]). This patch revamps btf_dump's padding logic significantly, making it more correct and also avoiding unnecessary explicit padding, where compiler would pad naturally. This overall topic turned out to be very tricky and subtle, there are lots of subtle corner cases. The comments in the code tries to give some clues, but comments themselves are supposed to be paired with good understanding of C alignment and padding rules. Plus some experimentation to figure out subtle things like whether `long :0;` means that struct is now forced to be long-aligned (no, it's not, turns out). Anyways, Per's script, while not completely correct in some known situations, doesn't show any obvious cases where this logic breaks, so this is a nice improvement over the previous state of this logic. Some selftests had to be adjusted to accommodate better use of natural alignment rules, eliminating some unnecessary padding, or changing it to `type: 0;` alignment markers. Note also that for when we are in between bitfields, we emit explicit bit size, while otherwise we use `: 0`, this feels much more natural in practice. Next patch will add few more test cases, found through randomized Per's script. [0] https://lore.kernel.org/bpf/85f83c333f5355c8ac026f835b18d15060725fcb.camel@ericsson.com/ Reported-by: Per Sundström XP <per.xp.sundstrom@ericsson.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20221212211505.558851-6-andrii@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-10libbpf: Fix alen calculation in libbpf_nla_dump_errormsg()Ilya Leoshkevich1-1/+1
[ Upstream commit 17bcd27a08a21397698edf143084d7c87ce17946 ] The code assumes that everything that comes after nlmsgerr are nlattrs. When calculating their size, it does not account for the initial nlmsghdr. This may lead to accessing uninitialized memory. Fixes: bbf48c18ee0c ("libbpf: add error reporting in XDP") Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230210001210.395194-8-iii@linux.ibm.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-10libbpf: Fix invalid return address register in s390Daniel T. Lee1-1/+1
[ Upstream commit 7244eb669397f309c3d014264823cdc9cb3f8e6b ] There is currently an invalid register mapping in the s390 return address register. As the manual[1] states, the return address can be found at r14. In bpf_tracing.h, the s390 registers were named gprs(general purpose registers). This commit fixes the problem by correcting the mistyped mapping. [1]: https://uclibc.org/docs/psABI-s390x.pdf#page=14 Fixes: 3cc31d794097 ("libbpf: Normalize PT_REGS_xxx() macro definitions") Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20221224071527.2292-7-danieltimlee@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-10libbpf: Fix btf__align_of() by taking into account field offsetsAndrii Nakryiko1-0/+13
[ Upstream commit 25a4481b4136af7794e1df2d6c90ed2f354d60ce ] btf__align_of() is supposed to be return alignment requirement of a requested BTF type. For STRUCT/UNION it doesn't always return correct value, because it calculates alignment only based on field types. But for packed structs this is not enough, we need to also check field offsets and struct size. If field offset isn't aligned according to field type's natural alignment, then struct must be packed. Similarly, if struct size is not a multiple of struct's natural alignment, then struct must be packed as well. This patch fixes this issue precisely by additionally checking these conditions. Fixes: 3d208f4ca111 ("libbpf: Expose btf__align_of() API") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20221212211505.558851-5-andrii@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31libbpf: Avoid enum forward-declarations in public API in C++ modeAndrii Nakryiko1-0/+7
[ Upstream commit b42693415b86f608049cf1b4870adc1dc65e58b0 ] C++ enum forward declarations are fundamentally not compatible with pure C enum definitions, and so libbpf's use of `enum bpf_stats_type;` forward declaration in libbpf/bpf.h public API header is causing C++ compilation issues. More details can be found in [0], but it comes down to C++ supporting enum forward declaration only with explicitly specified backing type: enum bpf_stats_type: int; In C (and I believe it's a GCC extension also), such forward declaration is simply: enum bpf_stats_type; Further, in Linux UAPI this enum is defined in pure C way: enum bpf_stats_type { BPF_STATS_RUN_TIME = 0; } And even though in both cases backing type is int, which can be confirmed by looking at DWARF information, for C++ compiler actual enum definition and forward declaration are incompatible. To eliminate this problem, for C++ mode define input argument as int, which makes enum unnecessary in libbpf public header. This solves the issue and as demonstrated by next patch doesn't cause any unwanted compiler warnings, at least with default warnings setting. [0] https://stackoverflow.com/questions/42766839/c11-enum-forward-causes-underlying-type-mismatch [1] Closes: https://github.com/libbpf/libbpf/issues/249 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20221130200013.2997831-1-andrii@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31libbpf: Btf dedup identical struct test needs check for nested structs/arraysAlan Maguire1-3/+5
[ Upstream commit f3c51fe02c55bd944662714e5b91b96dc271ad9f ] When examining module BTF, it is common to see core kernel structures such as sk_buff, net_device duplicated in the module. After adding debug messaging to BTF it turned out that much of the problem was down to the identical struct test failing during deduplication; sometimes the compiler adds identical structs. However it turns out sometimes that type ids of identical struct members can also differ, even when the containing structs are still identical. To take an example, for struct sk_buff, debug messaging revealed that the identical struct matching was failing for the anon struct "headers"; specifically for the first field: __u8 __pkt_type_offset[0]; /* 128 0 */ Looking at the code in BTF deduplication, we have code that guards against the possibility of identical struct definitions, down to type ids, and identical array definitions. However in this case we have a struct which is being defined twice but does not have identical type ids since each duplicate struct has separate type ids for the above array member. A similar problem (though not observed) could occur for struct-in-struct. The solution is to make the "identical struct" test check members not just for matching ids, but to also check if they in turn are identical structs or arrays. The results of doing this are quite dramatic (for some modules at least); I see the number of type ids drop from around 10000 to just over 1000 in one module for example. For testing use latest pahole or apply [1], otherwise dedups can fail for the reasons described there. Also fix return type of btf_dedup_identical_arrays() as suggested by Andrii to match boolean return type used elsewhere. Fixes: efdd3eb8015e ("libbpf: Accommodate DWARF/compiler bug with duplicated structs") Signed-off-by: Alan Maguire <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 Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31libbpf: Fix null-pointer dereference in find_prog_by_sec_insn()Shung-Hsi Yu1-0/+3
[ Upstream commit d0d382f95a9270dcf803539d6781d6bd67e3f5b2 ] When there are no program sections, obj->programs is left unallocated, and find_prog_by_sec_insn()'s search lands on &obj->programs[0] == NULL, and will cause null-pointer dereference in the following access to prog->sec_idx. Guard the search with obj->nr_programs similar to what's being done in __bpf_program__iter() to prevent null-pointer access from happening. Fixes: db2b8b06423c ("libbpf: Support CO-RE relocations for multi-prog sections") Signed-off-by: Shung-Hsi Yu <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 Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31libbpf: Deal with section with no data gracefullyShung-Hsi Yu1-1/+5
[ Upstream commit 35a855509e6ee3442477c8ebc6827b5b5d32a7b5 ] 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: cb1e5e961991 ("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 Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31libbpf: Use elf_getshdrnum() instead of e_shnumShung-Hsi Yu1-4/+9
[ Upstream commit 51deedc9b8680953437dfe359e5268120de10e30 ] 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: 0d6988e16a12 ("libbpf: Fix section counting logic") Fixes: 25bbbd7a444b ("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 Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31libbpf: Fix memory leak in parse_usdt_arg()Xu Kuohai1-7/+4
[ Upstream commit 0dc9254e03704c75f2ebc9cbef2ce4de83fba603 ] In the arm64 version of parse_usdt_arg(), when sscanf returns 2, reg_name is allocated but not freed. Fix it. Fixes: 0f8619929c57 ("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 Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31libbpf: Fix use-after-free in btf_dump_name_dupsXu Kuohai1-3/+26
[ Upstream commit 93c660ca40b5d2f7c1b1626e955a8e9fa30e0749 ] ASAN reports an use-after-free in btf_dump_name_dups: ERROR: AddressSanitizer: heap-use-after-free on address 0xffff927006db at pc 0xaaaab5dfb618 bp 0xffffdd89b890 sp 0xffffdd89b928 READ of size 2 at 0xffff927006db thread T0 #0 0xaaaab5dfb614 in __interceptor_strcmp.part.0 (test_progs+0x21b614) #1 0xaaaab635f144 in str_equal_fn tools/lib/bpf/btf_dump.c:127 #2 0xaaaab635e3e0 in hashmap_find_entry tools/lib/bpf/hashmap.c:143 #3 0xaaaab635e72c in hashmap__find tools/lib/bpf/hashmap.c:212 #4 0xaaaab6362258 in btf_dump_name_dups tools/lib/bpf/btf_dump.c:1525 #5 0xaaaab636240c in btf_dump_resolve_name tools/lib/bpf/btf_dump.c:1552 #6 0xaaaab6362598 in btf_dump_type_name tools/lib/bpf/btf_dump.c:1567 #7 0xaaaab6360b48 in btf_dump_emit_struct_def tools/lib/bpf/btf_dump.c:912 #8 0xaaaab6360630 in btf_dump_emit_type tools/lib/bpf/btf_dump.c:798 #9 0xaaaab635f720 in btf_dump__dump_type tools/lib/bpf/btf_dump.c:282 #10 0xaaaab608523c in test_btf_dump_incremental tools/testing/selftests/bpf/prog_tests/btf_dump.c:236 #11 0xaaaab6097530 in test_btf_dump tools/testing/selftests/bpf/prog_tests/btf_dump.c:875 #12 0xaaaab6314ed0 in run_one_test tools/testing/selftests/bpf/test_progs.c:1062 #13 0xaaaab631a0a8 in main tools/testing/selftests/bpf/test_progs.c:1697 #14 0xffff9676d214 in __libc_start_main ../csu/libc-start.c:308 #15 0xaaaab5d65990 (test_progs+0x185990) 0xffff927006db is located 11 bytes inside of 16-byte region [0xffff927006d0,0xffff927006e0) freed by thread T0 here: #0 0xaaaab5e2c7c4 in realloc (test_progs+0x24c7c4) #1 0xaaaab634f4a0 in libbpf_reallocarray tools/lib/bpf/libbpf_internal.h:191 #2 0xaaaab634f840 in libbpf_add_mem tools/lib/bpf/btf.c:163 #3 0xaaaab636643c in strset_add_str_mem tools/lib/bpf/strset.c:106 #4 0xaaaab6366560 in strset__add_str tools/lib/bpf/strset.c:157 #5 0xaaaab6352d70 in btf__add_str tools/lib/bpf/btf.c:1519 #6 0xaaaab6353e10 in btf__add_field tools/lib/bpf/btf.c:2032 #7 0xaaaab6084fcc in test_btf_dump_incremental tools/testing/selftests/bpf/prog_tests/btf_dump.c:232 #8 0xaaaab6097530 in test_btf_dump tools/testing/selftests/bpf/prog_tests/btf_dump.c:875 #9 0xaaaab6314ed0 in run_one_test tools/testing/selftests/bpf/test_progs.c:1062 #10 0xaaaab631a0a8 in main tools/testing/selftests/bpf/test_progs.c:1697 #11 0xffff9676d214 in __libc_start_main ../csu/libc-start.c:308 #12 0xaaaab5d65990 (test_progs+0x185990) previously allocated by thread T0 here: #0 0xaaaab5e2c7c4 in realloc (test_progs+0x24c7c4) #1 0xaaaab634f4a0 in libbpf_reallocarray tools/lib/bpf/libbpf_internal.h:191 #2 0xaaaab634f840 in libbpf_add_mem tools/lib/bpf/btf.c:163 #3 0xaaaab636643c in strset_add_str_mem tools/lib/bpf/strset.c:106 #4 0xaaaab6366560 in strset__add_str tools/lib/bpf/strset.c:157 #5 0xaaaab6352d70 in btf__add_str tools/lib/bpf/btf.c:1519 #6 0xaaaab6353ff0 in btf_add_enum_common tools/lib/bpf/btf.c:2070 #7 0xaaaab6354080 in btf__add_enum tools/lib/bpf/btf.c:2102 #8 0xaaaab6082f50 in test_btf_dump_incremental tools/testing/selftests/bpf/prog_tests/btf_dump.c:162 #9 0xaaaab6097530 in test_btf_dump tools/testing/selftests/bpf/prog_tests/btf_dump.c:875 #10 0xaaaab6314ed0 in run_one_test tools/testing/selftests/bpf/test_progs.c:1062 #11 0xaaaab631a0a8 in main tools/testing/selftests/bpf/test_progs.c:1697 #12 0xffff9676d214 in __libc_start_main ../csu/libc-start.c:308 #13 0xaaaab5d65990 (test_progs+0x185990) The reason is that the key stored in hash table name_map is a string address, and the string memory is allocated by realloc() function, when the memory is resized by realloc() later, the old memory may be freed, so the address stored in name_map references to a freed memory, causing use-after-free. Fix it by storing duplicated string address in name_map. Fixes: 919d2b1dbb07 ("libbpf: Allow modification of BTF and add btf__add_str API") Signed-off-by: Xu Kuohai <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 Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-21libbpf: Fix uninitialized warning in btf_dump_dump_type_dataDavid Michael1-1/+1
commit dfd0afbf151d85411b371e841f62b81ee5d1ca54 upstream. GCC 11.3.0 fails to compile btf_dump.c due to the following error, which seems to originate in btf_dump_struct_data where the returned value would be uninitialized if btf_vlen returns zero. btf_dump.c: In function ‘btf_dump_dump_type_data’: btf_dump.c:2363:12: error: ‘err’ may be used uninitialized in this function [-Werror=maybe-uninitialized] 2363 | if (err < 0) | ^ Fixes: 920d16af9b42 ("libbpf: BTF dumper support for typed data") Signed-off-by: David Michael <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 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-11-18libbpf: Check the validity of size in user_ring_buffer__reserve()Hou Tao1-0/+4
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
2022-11-18libbpf: Handle size overflow for user ringbuf mmapHou Tao1-2/+8
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: b66ccae01f1d ("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
2022-11-18libbpf: Handle size overflow for ringbuf mmapHou Tao1-4/+8
The maximum size of ringbuf is 2GB on x86-64 host, so 2 * max_entries will overflow u32 when mapping producer page and data pages. Only casting max_entries to size_t is not enough, because for 32-bits application on 64-bits kernel the size of read-only mmap region also could overflow size_t. So fixing it by casting the size of read-only mmap region into a __u64 and checking whether or not there will be overflow during mmap. Fixes: bf99c936f947 ("libbpf: Add BPF ring buffer support") Signed-off-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20221116072351.1168938-3-houtao@huaweicloud.com
2022-11-18libbpf: Use page size as max_entries when probing ring buffer mapHou Tao1-1/+1
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
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