kernel/linux.git/tools/lib, branch v5.10.268

bpf: reject negative CO-RE accessor indices in bpf_core_parse_spec()

2026-08-27T12:27:36+00:00

commit 1c22483a2c4bbf747787f328392ca3e68619c4dc upstream. CO-RE accessor strings are colon-separated indices that describe a path from a root BTF type to a target field, e.g. "0:1:2" walks through nested struct members. bpf_core_parse_spec() parses each component with sscanf("%d"), so negative values like -1 are silently accepted. The subsequent bounds checks (access_idx >= btf_vlen(t)) only guard the upper bound and always pass for negative values because C integer promotion converts the __u16 btf_vlen result to int, making the comparison (int)(-1) >= (int)(N) false for any positive N. When -1 reaches btf_member_bit_offset() it gets cast to u32 0xffffffff, producing an out-of-bounds read far past the members array. A crafted BPF program with a negative CO-RE accessor on any struct that exists in vmlinux BTF (e.g. task_struct) crashes the kernel deterministically during BPF_PROG_LOAD on any system with CONFIG_DEBUG_INFO_BTF=y (default on major distributions). The bug is reachable with CAP_BPF: BUG: unable to handle page fault for address: ffffed11818b6626 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page Oops: Oops: 0000 [#1] SMP KASAN NOPTI CPU: 0 UID: 0 PID: 85 Comm: poc Not tainted 7.0.0-rc6 #18 PREEMPT(full) RIP: 0010:bpf_core_parse_spec (tools/lib/bpf/relo_core.c:354) RAX: 00000000ffffffff Call Trace: bpf_core_calc_relo_insn (tools/lib/bpf/relo_core.c:1321) bpf_core_apply (kernel/bpf/btf.c:9507) check_core_relo (kernel/bpf/verifier.c:19475) bpf_check (kernel/bpf/verifier.c:26031) bpf_prog_load (kernel/bpf/syscall.c:3089) __sys_bpf (kernel/bpf/syscall.c:6228) CO-RE accessor indices are inherently non-negative (struct member index, array element index, or enumerator index), so reject them immediately after parsing. Fixes: ddc7c3042614 ("libbpf: implement BPF CO-RE offset relocation algorithm") Reported-by: Xiang Mei Signed-off-by: Weiming Shi Reviewed-by: Emil Tsalapatis Acked-by: Paul Chaignon Link: https://lore.kernel.org/r/20260404161221.961828-2-bestswngs@gmail.com Signed-off-by: Alexei Starovoitov [Andrey Troshin: backport fixs from tools/lib/bpf/relo_core.c to tools/lib/bpf/libbpf.c] Signed-off-by: Andrey Troshin Signed-off-by: Greg Kroah-Hartman

tools lib api: Fix mount_overload() snprintf truncation and toupper range

2026-07-24T13:49:02+00:00

[ Upstream commit fd1f70776add263f8ef38a87ae593c75303f1dcd ] mount_overload() builds an environment variable name like "PERF_SYSFS_ENVIRONMENT" from fs->name. Two bugs: 1) snprintf() uses name_len as the buffer size instead of sizeof(upper_name). For fs->name = "sysfs" (len=5), the output is truncated to "PERF" (4 chars + null), so getenv() never finds the intended variable. 2) mem_toupper() only uppercases name_len bytes, converting just the "PERF" prefix rather than the full string including the filesystem name portion. Fix by using sizeof(upper_name) for snprintf and strlen(upper_name) for mem_toupper, so the full "PERF_SYSFS_ENVIRONMENT" string is correctly formatted and uppercased. Reported-by: sashiko-bot Fixes: 73ca85ad364769ff ("tools lib api fs: Add FSTYPE__mount() method") Cc: Jiri Olsa Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin

tools lib api: Fix filename__write_int() writing uninitialized stack data

2026-07-24T13:49:02+00:00

[ Upstream commit 438ece06185696e14c63c6113d5e2d34ec0a9680 ] filename__write_int() formats an integer into a 64-byte buffer with sprintf() then passes sizeof(buf) (64) as the write length. This writes all 64 bytes including uninitialized stack data past the formatted string. Most sysfs files reject the oversized write, making the function always return -1. Fix by capturing the sprintf() return value and using it as the write length. Reported-by: sashiko-bot Fixes: 3b00ea938653d136 ("tools lib api fs: Add sysfs__write_int function") Cc: Kan Liang Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin

tools lib api: Fix missing null termination in filename__read_int/ull()

2026-07-24T13:49:02+00:00

[ Upstream commit 52b1f9678499b13b7aeb0186d9c6f486c043283f ] filename__read_int() passes a stack buffer to read() using the full sizeof(line) and then hands it to atoi() without null-terminating. If a sysfs file fills the 64-byte buffer exactly, atoi() reads past the array into uninitialized stack memory. filename__read_ull_base() has the same issue with strtoull(). Fix both by reading sizeof(line) - 1 bytes and explicitly null-terminating after a successful read. Fixes: 3a351127cbc682c3 ("tools lib fs: Adopt filename__read_int from tools/perf/") Reported-by: sashiko-bot Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin

libperf event: Ensure tracing data is multiple of 8 sized

2025-10-29T13:01:08+00:00

[ Upstream commit b39c915a4f365cce6bdc0e538ed95d31823aea8f ] Perf's synthetic-events.c will ensure 8-byte alignment of tracing data, writing it after a perf_record_header_tracing_data event. Add padding to struct perf_record_header_tracing_data to make it 16-byte rather than 12-byte sized. Fixes: 055c67ed39887c55 ("perf tools: Move event synthesizing routines to separate .c file") Reviewed-by: James Clark Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Athira Rajeev Cc: Blake Jones Cc: Chun-Tse Shao Cc: Collin Funk Cc: Howard Chu Cc: Ingo Molnar Cc: Jan Polensky Cc: Jiri Olsa Cc: Kan Liang Cc: Li Huafei Cc: Mark Rutland Cc: Nam Cao Cc: Peter Zijlstra Cc: Steinar H. Gunderson Cc: Thomas Gleixner Link: https://lore.kernel.org/r/20250821163820.1132977-6-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin

libbpf: Fix reuse of DEVMAP

2025-10-29T13:01:03+00:00

[ 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 Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250814180113.1245565-3-yuka@yuka.dev Signed-off-by: Sasha Levin

perf subcmd: avoid crash in exclude_cmds when excludes is empty

2025-10-29T13:01:02+00:00

[ Upstream commit a5edf3550f4260504b7e0ab3d40d13ffe924b773 ] When cross-compiling the perf tool for ARM64, `perf help` may crash with the following assertion failure: help.c:122: exclude_cmds: Assertion `cmds->names[ci] == NULL' failed. This happens when the perf binary is not named exactly "perf" or when multiple "perf-*" binaries exist in the same directory. In such cases, the `excludes` command list can be empty, which leads to the final assertion in exclude_cmds() being triggered. Add a simple guard at the beginning of exclude_cmds() to return early if excludes->cnt is zero, preventing the crash. Signed-off-by: hupu Reported-by: Guilherme Amadio Reviewed-by: Namhyung Kim Link: https://lore.kernel.org/r/20250909094953.106706-1-amadio@gentoo.org Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin

libbpf: Fix null pointer dereference in btf_dump__free on allocation failure

2025-07-17T16:27:41+00:00

[ 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 Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250618011933.11423-1-chenyuan_fl@163.com Signed-off-by: Sasha Levin

libbpf: Use proper errno value in nlattr

2025-06-27T10:04:03+00:00

[ 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 Signed-off-by: Anton Protopopov Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250510182011.2246631-1-a.s.protopopov@gmail.com Signed-off-by: Sasha Levin

libbpf: Fix out-of-bound read

2025-06-04T12:37:03+00:00

[ 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 Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250221210110.3182084-1-nandakumar@nandakumar.co.in Signed-off-by: Sasha Levin