From 7e61560628d17ea6b1d8ee370f6d42694cff8758 Mon Sep 17 00:00:00 2001 From: Ulises Mendez Martinez Date: Fri, 4 Sep 2026 15:07:09 +0000 Subject: objtool: Validate disassembler headers in libopcodes probe commit 3f2de814c059 ("objtool: Fix libopcodes linking with static libraries") tested for libopcodes availability by linking a test snippet with a forward declaration of disassemble_init_for_target(). However, testing symbol linkage with an extern declaration only verifies the presence of the library (.so/.a) and bypasses checking for development headers (binutils-dev). On systems where libopcodes is present without development headers installed, the probe succeeds, enabling BUILD_DISAS. Subsequent compilation of objtool then fails: fatal error: 'bfd.h' file not found 113 | #include Additionally, the probe invokes $(HOSTCC) without $(HOSTCFLAGS), ignoring any sysroot or include flags specified for the host compiler. Fix this by including and directly in the test snippet, passing $(HOSTCFLAGS) so host compiler options are respected, and defining PACKAGE="objtool" to satisfy the configuration check in . Fixes: 3f2de814c059 ("objtool: Fix libopcodes linking with static libraries") Fixes: 436326bc525d ("objtool: fix build failure due to missing libopcodes check") Reported-by: Alice Ryhl Assisted-by: Antigravity:Gemini-Next Signed-off-by: Ulises Mendez Martinez Link: https://patch.msgid.link/20260904150710.2997558-1-umendez@google.com Signed-off-by: Josh Poimboeuf --- samples/bpf/sock_example.c | 111 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 111 insertions(+) create mode 100644 samples/bpf/sock_example.c (limited to 'samples/bpf/sock_example.c') diff --git a/samples/bpf/sock_example.c b/samples/bpf/sock_example.c new file mode 100644 index 000000000..5b66f2401 --- /dev/null +++ b/samples/bpf/sock_example.c @@ -0,0 +1,111 @@ +/* eBPF example program: + * - creates arraymap in kernel with key 4 bytes and value 8 bytes + * + * - loads eBPF program: + * r0 = skb->data[ETH_HLEN + offsetof(struct iphdr, protocol)]; + * *(u32*)(fp - 4) = r0; + * // assuming packet is IPv4, lookup ip->proto in a map + * value = bpf_map_lookup_elem(map_fd, fp - 4); + * if (value) + * (*(u64*)value) += 1; + * + * - attaches this program to loopback interface "lo" raw socket + * + * - every second user space reads map[tcp], map[udp], map[icmp] to see + * how many packets of given protocol were seen on "lo" + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "bpf_insn.h" +#include "sock_example.h" +#include "bpf_util.h" + +char bpf_log_buf[BPF_LOG_BUF_SIZE]; + +static int test_sock(void) +{ + int sock = -1, map_fd, prog_fd, i, key; + long long value = 0, tcp_cnt, udp_cnt, icmp_cnt; + + map_fd = bpf_map_create(BPF_MAP_TYPE_ARRAY, NULL, sizeof(key), sizeof(value), + 256, NULL); + if (map_fd < 0) { + printf("failed to create map '%s'\n", strerror(errno)); + goto cleanup; + } + + struct bpf_insn prog[] = { + BPF_MOV64_REG(BPF_REG_6, BPF_REG_1), + BPF_LD_ABS(BPF_B, ETH_HLEN + offsetof(struct iphdr, protocol) /* R0 = ip->proto */), + BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4), /* *(u32 *)(fp - 4) = r0 */ + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), /* r2 = fp - 4 */ + BPF_LD_MAP_FD(BPF_REG_1, map_fd), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2), + BPF_MOV64_IMM(BPF_REG_1, 1), /* r1 = 1 */ + BPF_ATOMIC_OP(BPF_DW, BPF_ADD, BPF_REG_0, BPF_REG_1, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), /* r0 = 0 */ + BPF_EXIT_INSN(), + }; + size_t insns_cnt = ARRAY_SIZE(prog); + LIBBPF_OPTS(bpf_prog_load_opts, opts, + .log_buf = bpf_log_buf, + .log_size = BPF_LOG_BUF_SIZE, + ); + + prog_fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL", + prog, insns_cnt, &opts); + if (prog_fd < 0) { + printf("failed to load prog '%s'\n", strerror(errno)); + goto cleanup; + } + + sock = open_raw_sock("lo"); + + if (setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, &prog_fd, + sizeof(prog_fd)) < 0) { + printf("setsockopt %s\n", strerror(errno)); + goto cleanup; + } + + for (i = 0; i < 10; i++) { + key = IPPROTO_TCP; + assert(bpf_map_lookup_elem(map_fd, &key, &tcp_cnt) == 0); + + key = IPPROTO_UDP; + assert(bpf_map_lookup_elem(map_fd, &key, &udp_cnt) == 0); + + key = IPPROTO_ICMP; + assert(bpf_map_lookup_elem(map_fd, &key, &icmp_cnt) == 0); + + printf("TCP %lld UDP %lld ICMP %lld packets\n", + tcp_cnt, udp_cnt, icmp_cnt); + sleep(1); + } + +cleanup: + /* maps, programs, raw sockets will auto cleanup on process exit */ + return 0; +} + +int main(void) +{ + FILE *f; + + f = popen("ping -4 -c5 localhost", "r"); + (void)f; + + return test_sock(); +} -- cgit v1.3.1