--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+
+#include <limits.h>
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include <regex.h>
+#include <test_progs.h>
+
+#include "bpf/btf.h"
+#include "bpf_util.h"
+#include "linux/filter.h"
+#include "disasm.h"
+
+#define MAX_PROG_TEXT_SZ (32 * 1024)
+
+/* The code in this file serves the sole purpose of executing test cases
+ * specified in the test_cases array. Each test case specifies a program
+ * type, context field offset, and disassembly patterns that correspond
+ * to read and write instructions generated by
+ * verifier.c:convert_ctx_access() for accessing that field.
+ *
+ * For each test case, up to three programs are created:
+ * - One that uses BPF_LDX_MEM to read the context field.
+ * - One that uses BPF_STX_MEM to write to the context field.
+ * - One that uses BPF_ST_MEM to write to the context field.
+ *
+ * The disassembly of each program is then compared with the pattern
+ * specified in the test case.
+ */
+struct test_case {
+ char *name;
+ enum bpf_prog_type prog_type;
+ enum bpf_attach_type expected_attach_type;
+ int field_offset;
+ int field_sz;
+ /* Program generated for BPF_ST_MEM uses value 42 by default,
+ * this field allows to specify custom value.
+ */
+ struct {
+ bool use;
+ int value;
+ } st_value;
+ /* Pattern for BPF_LDX_MEM(field_sz, dst, ctx, field_offset) */
+ char *read;
+ /* Pattern for BPF_STX_MEM(field_sz, ctx, src, field_offset) and
+ * BPF_ST_MEM (field_sz, ctx, src, field_offset)
+ */
+ char *write;
+ /* Pattern for BPF_ST_MEM(field_sz, ctx, src, field_offset),
+ * takes priority over `write`.
+ */
+ char *write_st;
+ /* Pattern for BPF_STX_MEM (field_sz, ctx, src, field_offset),
+ * takes priority over `write`.
+ */
+ char *write_stx;
+};
+
+#define N(_prog_type, type, field, name_extra...) \
+ .name = #_prog_type "." #field name_extra, \
+ .prog_type = BPF_PROG_TYPE_##_prog_type, \
+ .field_offset = offsetof(type, field), \
+ .field_sz = sizeof(typeof(((type *)NULL)->field))
+
+static struct test_case test_cases[] = {
+/* Sign extension on s390 changes the pattern */
+#if defined(__x86_64__) || defined(__aarch64__)
+ {
+ N(SCHED_CLS, struct __sk_buff, tstamp),
+ .read = "r11 = *(u8 *)($ctx + sk_buff::__pkt_vlan_present_offset);"
+ "w11 &= 160;"
+ "if w11 != 0xa0 goto pc+2;"
+ "$dst = 0;"
+ "goto pc+1;"
+ "$dst = *(u64 *)($ctx + sk_buff::tstamp);",
+ .write = "r11 = *(u8 *)($ctx + sk_buff::__pkt_vlan_present_offset);"
+ "if w11 & 0x80 goto pc+1;"
+ "goto pc+2;"
+ "w11 &= -33;"
+ "*(u8 *)($ctx + sk_buff::__pkt_vlan_present_offset) = r11;"
+ "*(u64 *)($ctx + sk_buff::tstamp) = $src;",
+ },
+#endif
+ {
+ N(SCHED_CLS, struct __sk_buff, priority),
+ .read = "$dst = *(u32 *)($ctx + sk_buff::priority);",
+ .write = "*(u32 *)($ctx + sk_buff::priority) = $src;",
+ },
+ {
+ N(SCHED_CLS, struct __sk_buff, mark),
+ .read = "$dst = *(u32 *)($ctx + sk_buff::mark);",
+ .write = "*(u32 *)($ctx + sk_buff::mark) = $src;",
+ },
+ {
+ N(SCHED_CLS, struct __sk_buff, cb[0]),
+ .read = "$dst = *(u32 *)($ctx + $(sk_buff::cb + qdisc_skb_cb::data));",
+ .write = "*(u32 *)($ctx + $(sk_buff::cb + qdisc_skb_cb::data)) = $src;",
+ },
+ {
+ N(SCHED_CLS, struct __sk_buff, tc_classid),
+ .read = "$dst = *(u16 *)($ctx + $(sk_buff::cb + qdisc_skb_cb::tc_classid));",
+ .write = "*(u16 *)($ctx + $(sk_buff::cb + qdisc_skb_cb::tc_classid)) = $src;",
+ },
+ {
+ N(SCHED_CLS, struct __sk_buff, tc_index),
+ .read = "$dst = *(u16 *)($ctx + sk_buff::tc_index);",
+ .write = "*(u16 *)($ctx + sk_buff::tc_index) = $src;",
+ },
+ {
+ N(SCHED_CLS, struct __sk_buff, queue_mapping),
+ .read = "$dst = *(u16 *)($ctx + sk_buff::queue_mapping);",
+ .write_stx = "if $src >= 0xffff goto pc+1;"
+ "*(u16 *)($ctx + sk_buff::queue_mapping) = $src;",
+ .write_st = "*(u16 *)($ctx + sk_buff::queue_mapping) = $src;",
+ },
+ {
+ /* This is a corner case in filter.c:bpf_convert_ctx_access() */
+ N(SCHED_CLS, struct __sk_buff, queue_mapping, ".ushrt_max"),
+ .st_value = { true, USHRT_MAX },
+ .write_st = "goto pc+0;",
+ },
+ {
+ N(CGROUP_SOCK, struct bpf_sock, bound_dev_if),
+ .read = "$dst = *(u32 *)($ctx + sock_common::skc_bound_dev_if);",
+ .write = "*(u32 *)($ctx + sock_common::skc_bound_dev_if) = $src;",
+ },
+ {
+ N(CGROUP_SOCK, struct bpf_sock, mark),
+ .read = "$dst = *(u32 *)($ctx + sock::sk_mark);",
+ .write = "*(u32 *)($ctx + sock::sk_mark) = $src;",
+ },
+ {
+ N(CGROUP_SOCK, struct bpf_sock, priority),
+ .read = "$dst = *(u32 *)($ctx + sock::sk_priority);",
+ .write = "*(u32 *)($ctx + sock::sk_priority) = $src;",
+ },
+ {
+ N(SOCK_OPS, struct bpf_sock_ops, replylong[0]),
+ .read = "$dst = *(u32 *)($ctx + bpf_sock_ops_kern::replylong);",
+ .write = "*(u32 *)($ctx + bpf_sock_ops_kern::replylong) = $src;",
+ },
+ {
+ N(CGROUP_SYSCTL, struct bpf_sysctl, file_pos),
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+ .read = "$dst = *(u64 *)($ctx + bpf_sysctl_kern::ppos);"
+ "$dst = *(u32 *)($dst +0);",
+ .write = "*(u64 *)($ctx + bpf_sysctl_kern::tmp_reg) = r9;"
+ "r9 = *(u64 *)($ctx + bpf_sysctl_kern::ppos);"
+ "*(u32 *)(r9 +0) = $src;"
+ "r9 = *(u64 *)($ctx + bpf_sysctl_kern::tmp_reg);",
+#else
+ .read = "$dst = *(u64 *)($ctx + bpf_sysctl_kern::ppos);"
+ "$dst = *(u32 *)($dst +4);",
+ .write = "*(u64 *)($ctx + bpf_sysctl_kern::tmp_reg) = r9;"
+ "r9 = *(u64 *)($ctx + bpf_sysctl_kern::ppos);"
+ "*(u32 *)(r9 +4) = $src;"
+ "r9 = *(u64 *)($ctx + bpf_sysctl_kern::tmp_reg);",
+#endif
+ },
+ {
+ N(CGROUP_SOCKOPT, struct bpf_sockopt, sk),
+ .read = "$dst = *(u64 *)($ctx + bpf_sockopt_kern::sk);",
+ .expected_attach_type = BPF_CGROUP_GETSOCKOPT,
+ },
+ {
+ N(CGROUP_SOCKOPT, struct bpf_sockopt, level),
+ .read = "$dst = *(u32 *)($ctx + bpf_sockopt_kern::level);",
+ .write = "*(u32 *)($ctx + bpf_sockopt_kern::level) = $src;",
+ .expected_attach_type = BPF_CGROUP_SETSOCKOPT,
+ },
+ {
+ N(CGROUP_SOCKOPT, struct bpf_sockopt, optname),
+ .read = "$dst = *(u32 *)($ctx + bpf_sockopt_kern::optname);",
+ .write = "*(u32 *)($ctx + bpf_sockopt_kern::optname) = $src;",
+ .expected_attach_type = BPF_CGROUP_SETSOCKOPT,
+ },
+ {
+ N(CGROUP_SOCKOPT, struct bpf_sockopt, optlen),
+ .read = "$dst = *(u32 *)($ctx + bpf_sockopt_kern::optlen);",
+ .write = "*(u32 *)($ctx + bpf_sockopt_kern::optlen) = $src;",
+ .expected_attach_type = BPF_CGROUP_SETSOCKOPT,
+ },
+ {
+ N(CGROUP_SOCKOPT, struct bpf_sockopt, retval),
+ .read = "$dst = *(u64 *)($ctx + bpf_sockopt_kern::current_task);"
+ "$dst = *(u64 *)($dst + task_struct::bpf_ctx);"
+ "$dst = *(u32 *)($dst + bpf_cg_run_ctx::retval);",
+ .write = "*(u64 *)($ctx + bpf_sockopt_kern::tmp_reg) = r9;"
+ "r9 = *(u64 *)($ctx + bpf_sockopt_kern::current_task);"
+ "r9 = *(u64 *)(r9 + task_struct::bpf_ctx);"
+ "*(u32 *)(r9 + bpf_cg_run_ctx::retval) = $src;"
+ "r9 = *(u64 *)($ctx + bpf_sockopt_kern::tmp_reg);",
+ .expected_attach_type = BPF_CGROUP_GETSOCKOPT,
+ },
+ {
+ N(CGROUP_SOCKOPT, struct bpf_sockopt, optval),
+ .read = "$dst = *(u64 *)($ctx + bpf_sockopt_kern::optval);",
+ .expected_attach_type = BPF_CGROUP_GETSOCKOPT,
+ },
+ {
+ N(CGROUP_SOCKOPT, struct bpf_sockopt, optval_end),
+ .read = "$dst = *(u64 *)($ctx + bpf_sockopt_kern::optval_end);",
+ .expected_attach_type = BPF_CGROUP_GETSOCKOPT,
+ },
+};
+
+#undef N
+
+static regex_t *ident_regex;
+static regex_t *field_regex;
+
+static char *skip_space(char *str)
+{
+ while (*str && isspace(*str))
+ ++str;
+ return str;
+}
+
+static char *skip_space_and_semi(char *str)
+{
+ while (*str && (isspace(*str) || *str == ';'))
+ ++str;
+ return str;
+}
+
+static char *match_str(char *str, char *prefix)
+{
+ while (*str && *prefix && *str == *prefix) {
+ ++str;
+ ++prefix;
+ }
+ if (*prefix)
+ return NULL;
+ return str;
+}
+
+static char *match_number(char *str, int num)
+{
+ char *next;
+ int snum = strtol(str, &next, 10);
+
+ if (next - str == 0 || num != snum)
+ return NULL;
+
+ return next;
+}
+
+static int find_field_offset_aux(struct btf *btf, int btf_id, char *field_name, int off)
+{
+ const struct btf_type *type = btf__type_by_id(btf, btf_id);
+ const struct btf_member *m;
+ __u16 mnum;
+ int i;
+
+ if (!type) {
+ PRINT_FAIL("Can't find btf_type for id %d\n", btf_id);
+ return -1;
+ }
+
+ if (!btf_is_struct(type) && !btf_is_union(type)) {
+ PRINT_FAIL("BTF id %d is not struct or union\n", btf_id);
+ return -1;
+ }
+
+ m = btf_members(type);
+ mnum = btf_vlen(type);
+
+ for (i = 0; i < mnum; ++i, ++m) {
+ const char *mname = btf__name_by_offset(btf, m->name_off);
+
+ if (strcmp(mname, "") == 0) {
+ int msize = find_field_offset_aux(btf, m->type, field_name,
+ off + m->offset);
+ if (msize >= 0)
+ return msize;
+ }
+
+ if (strcmp(mname, field_name))
+ continue;
+
+ return (off + m->offset) / 8;
+ }
+
+ return -1;
+}
+
+static int find_field_offset(struct btf *btf, char *pattern, regmatch_t *matches)
+{
+ int type_sz = matches[1].rm_eo - matches[1].rm_so;
+ int field_sz = matches[2].rm_eo - matches[2].rm_so;
+ char *type = pattern + matches[1].rm_so;
+ char *field = pattern + matches[2].rm_so;
+ char field_str[128] = {};
+ char type_str[128] = {};
+ int btf_id, field_offset;
+
+ if (type_sz >= sizeof(type_str)) {
+ PRINT_FAIL("Malformed pattern: type ident is too long: %d\n", type_sz);
+ return -1;
+ }
+
+ if (field_sz >= sizeof(field_str)) {
+ PRINT_FAIL("Malformed pattern: field ident is too long: %d\n", field_sz);
+ return -1;
+ }
+
+ strncpy(type_str, type, type_sz);
+ strncpy(field_str, field, field_sz);
+ btf_id = btf__find_by_name(btf, type_str);
+ if (btf_id < 0) {
+ PRINT_FAIL("No BTF info for type %s\n", type_str);
+ return -1;
+ }
+
+ field_offset = find_field_offset_aux(btf, btf_id, field_str, 0);
+ if (field_offset < 0) {
+ PRINT_FAIL("No BTF info for field %s::%s\n", type_str, field_str);
+ return -1;
+ }
+
+ return field_offset;
+}
+
+static regex_t *compile_regex(char *pat)
+{
+ regex_t *re;
+ int err;
+
+ re = malloc(sizeof(regex_t));
+ if (!re) {
+ PRINT_FAIL("Can't alloc regex\n");
+ return NULL;
+ }
+
+ err = regcomp(re, pat, REG_EXTENDED);
+ if (err) {
+ char errbuf[512];
+
+ regerror(err, re, errbuf, sizeof(errbuf));
+ PRINT_FAIL("Can't compile regex: %s\n", errbuf);
+ free(re);
+ return NULL;
+ }
+
+ return re;
+}
+
+static void free_regex(regex_t *re)
+{
+ if (!re)
+ return;
+
+ regfree(re);
+ free(re);
+}
+
+static u32 max_line_len(char *str)
+{
+ u32 max_line = 0;
+ char *next = str;
+
+ while (next) {
+ next = strchr(str, '\n');
+ if (next) {
+ max_line = max_t(u32, max_line, (next - str));
+ str = next + 1;
+ } else {
+ max_line = max_t(u32, max_line, strlen(str));
+ }
+ }
+
+ return min(max_line, 60u);
+}
+
+/* Print strings `pattern_origin` and `text_origin` side by side,
+ * assume `pattern_pos` and `text_pos` designate location within
+ * corresponding origin string where match diverges.
+ * The output should look like:
+ *
+ * Can't match disassembly(left) with pattern(right):
+ * r2 = *(u64 *)(r1 +0) ; $dst = *(u64 *)($ctx + bpf_sockopt_kern::sk1)
+ * ^ ^
+ * r0 = 0 ;
+ * exit ;
+ */
+static void print_match_error(FILE *out,
+ char *pattern_origin, char *text_origin,
+ char *pattern_pos, char *text_pos)
+{
+ char *pattern = pattern_origin;
+ char *text = text_origin;
+ int middle = max_line_len(text) + 2;
+
+ fprintf(out, "Can't match disassembly(left) with pattern(right):\n");
+ while (*pattern || *text) {
+ int column = 0;
+ int mark1 = -1;
+ int mark2 = -1;
+
+ /* Print one line from text */
+ while (*text && *text != '\n') {
+ if (text == text_pos)
+ mark1 = column;
+ fputc(*text, out);
+ ++text;
+ ++column;
+ }
+ if (text == text_pos)
+ mark1 = column;
+
+ /* Pad to the middle */
+ while (column < middle) {
+ fputc(' ', out);
+ ++column;
+ }
+ fputs("; ", out);
+ column += 3;
+
+ /* Print one line from pattern, pattern lines are terminated by ';' */
+ while (*pattern && *pattern != ';') {
+ if (pattern == pattern_pos)
+ mark2 = column;
+ fputc(*pattern, out);
+ ++pattern;
+ ++column;
+ }
+ if (pattern == pattern_pos)
+ mark2 = column;
+
+ fputc('\n', out);
+ if (*pattern)
+ ++pattern;
+ if (*text)
+ ++text;
+
+ /* If pattern and text diverge at this line, print an
+ * additional line with '^' marks, highlighting
+ * positions where match fails.
+ */
+ if (mark1 > 0 || mark2 > 0) {
+ for (column = 0; column <= max(mark1, mark2); ++column) {
+ if (column == mark1 || column == mark2)
+ fputc('^', out);
+ else
+ fputc(' ', out);
+ }
+ fputc('\n', out);
+ }
+ }
+}
+
+/* Test if `text` matches `pattern`. Pattern consists of the following elements:
+ *
+ * - Field offset references:
+ *
+ * <type>::<field>
+ *
+ * When such reference is encountered BTF is used to compute numerical
+ * value for the offset of <field> in <type>. The `text` is expected to
+ * contain matching numerical value.
+ *
+ * - Field groups:
+ *
+ * $(<type>::<field> [+ <type>::<field>]*)
+ *
+ * Allows to specify an offset that is a sum of multiple field offsets.
+ * The `text` is expected to contain matching numerical value.
+ *
+ * - Variable references, e.g. `$src`, `$dst`, `$ctx`.
+ * These are substitutions specified in `reg_map` array.
+ * If a substring of pattern is equal to `reg_map[i][0]` the `text` is
+ * expected to contain `reg_map[i][1]` in the matching position.
+ *
+ * - Whitespace is ignored, ';' counts as whitespace for `pattern`.
+ *
+ * - Any other characters, `pattern` and `text` should match one-to-one.
+ *
+ * Example of a pattern:
+ *
+ * __________ fields group ________________
+ * ' '
+ * *(u16 *)($ctx + $(sk_buff::cb + qdisc_skb_cb::tc_classid)) = $src;
+ * ^^^^ '______________________'
+ * variable reference field offset reference
+ */
+static bool match_pattern(struct btf *btf, char *pattern, char *text, char *reg_map[][2])
+{
+ char *pattern_origin = pattern;
+ char *text_origin = text;
+ regmatch_t matches[3];
+
+_continue:
+ while (*pattern) {
+ if (!*text)
+ goto err;
+
+ /* Skip whitespace */
+ if (isspace(*pattern) || *pattern == ';') {
+ if (!isspace(*text) && text != text_origin && isalnum(text[-1]))
+ goto err;
+ pattern = skip_space_and_semi(pattern);
+ text = skip_space(text);
+ continue;
+ }
+
+ /* Check for variable references */
+ for (int i = 0; reg_map[i][0]; ++i) {
+ char *pattern_next, *text_next;
+
+ pattern_next = match_str(pattern, reg_map[i][0]);
+ if (!pattern_next)
+ continue;
+
+ text_next = match_str(text, reg_map[i][1]);
+ if (!text_next)
+ goto err;
+
+ pattern = pattern_next;
+ text = text_next;
+ goto _continue;
+ }
+
+ /* Match field group:
+ * $(sk_buff::cb + qdisc_skb_cb::tc_classid)
+ */
+ if (strncmp(pattern, "$(", 2) == 0) {
+ char *group_start = pattern, *text_next;
+ int acc_offset = 0;
+
+ pattern += 2;
+
+ for (;;) {
+ int field_offset;
+
+ pattern = skip_space(pattern);
+ if (!*pattern) {
+ PRINT_FAIL("Unexpected end of pattern\n");
+ goto err;
+ }
+
+ if (*pattern == ')') {
+ ++pattern;
+ break;
+ }
+
+ if (*pattern == '+') {
+ ++pattern;
+ continue;
+ }
+
+ printf("pattern: %s\n", pattern);
+ if (regexec(field_regex, pattern, 3, matches, 0) != 0) {
+ PRINT_FAIL("Field reference expected\n");
+ goto err;
+ }
+
+ field_offset = find_field_offset(btf, pattern, matches);
+ if (field_offset < 0)
+ goto err;
+
+ pattern += matches[0].rm_eo;
+ acc_offset += field_offset;
+ }
+
+ text_next = match_number(text, acc_offset);
+ if (!text_next) {
+ PRINT_FAIL("No match for group offset %.*s (%d)\n",
+ (int)(pattern - group_start),
+ group_start,
+ acc_offset);
+ goto err;
+ }
+ text = text_next;
+ }
+
+ /* Match field reference:
+ * sk_buff::cb
+ */
+ if (regexec(field_regex, pattern, 3, matches, 0) == 0) {
+ int field_offset;
+ char *text_next;
+
+ field_offset = find_field_offset(btf, pattern, matches);
+ if (field_offset < 0)
+ goto err;
+
+ text_next = match_number(text, field_offset);
+ if (!text_next) {
+ PRINT_FAIL("No match for field offset %.*s (%d)\n",
+ (int)matches[0].rm_eo, pattern, field_offset);
+ goto err;
+ }
+
+ pattern += matches[0].rm_eo;
+ text = text_next;
+ continue;
+ }
+
+ /* If pattern points to identifier not followed by '::'
+ * skip the identifier to avoid n^2 application of the
+ * field reference rule.
+ */
+ if (regexec(ident_regex, pattern, 1, matches, 0) == 0) {
+ if (strncmp(pattern, text, matches[0].rm_eo) != 0)
+ goto err;
+
+ pattern += matches[0].rm_eo;
+ text += matches[0].rm_eo;
+ continue;
+ }
+
+ /* Match literally */
+ if (*pattern != *text)
+ goto err;
+
+ ++pattern;
+ ++text;
+ }
+
+ return true;
+
+err:
+ test__fail();
+ print_match_error(stdout, pattern_origin, text_origin, pattern, text);
+ return false;
+}
+
+/* Request BPF program instructions after all rewrites are applied,
+ * e.g. verifier.c:convert_ctx_access() is done.
+ */
+static int get_xlated_program(int fd_prog, struct bpf_insn **buf, __u32 *cnt)
+{
+ struct bpf_prog_info info = {};
+ __u32 info_len = sizeof(info);
+ __u32 xlated_prog_len;
+ __u32 buf_element_size = sizeof(struct bpf_insn);
+
+ if (bpf_prog_get_info_by_fd(fd_prog, &info, &info_len)) {
+ perror("bpf_prog_get_info_by_fd failed");
+ return -1;
+ }
+
+ xlated_prog_len = info.xlated_prog_len;
+ if (xlated_prog_len % buf_element_size) {
+ printf("Program length %d is not multiple of %d\n",
+ xlated_prog_len, buf_element_size);
+ return -1;
+ }
+
+ *cnt = xlated_prog_len / buf_element_size;
+ *buf = calloc(*cnt, buf_element_size);
+ if (!buf) {
+ perror("can't allocate xlated program buffer");
+ return -ENOMEM;
+ }
+
+ bzero(&info, sizeof(info));
+ info.xlated_prog_len = xlated_prog_len;
+ info.xlated_prog_insns = (__u64)(unsigned long)*buf;
+ if (bpf_prog_get_info_by_fd(fd_prog, &info, &info_len)) {
+ perror("second bpf_prog_get_info_by_fd failed");
+ goto out_free_buf;
+ }
+
+ return 0;
+
+out_free_buf:
+ free(*buf);
+ return -1;
+}
+
+static void print_insn(void *private_data, const char *fmt, ...)
+{
+ va_list args;
+
+ va_start(args, fmt);
+ vfprintf((FILE *)private_data, fmt, args);
+ va_end(args);
+}
+
+/* Disassemble instructions to a stream */
+static void print_xlated(FILE *out, struct bpf_insn *insn, __u32 len)
+{
+ const struct bpf_insn_cbs cbs = {
+ .cb_print = print_insn,
+ .cb_call = NULL,
+ .cb_imm = NULL,
+ .private_data = out,
+ };
+ bool double_insn = false;
+ int i;
+
+ for (i = 0; i < len; i++) {
+ if (double_insn) {
+ double_insn = false;
+ continue;
+ }
+
+ double_insn = insn[i].code == (BPF_LD | BPF_IMM | BPF_DW);
+ print_bpf_insn(&cbs, insn + i, true);
+ }
+}
+
+/* We share code with kernel BPF disassembler, it adds '(FF) ' prefix
+ * for each instruction (FF stands for instruction `code` byte).
+ * This function removes the prefix inplace for each line in `str`.
+ */
+static void remove_insn_prefix(char *str, int size)
+{
+ const int prefix_size = 5;
+
+ int write_pos = 0, read_pos = prefix_size;
+ int len = strlen(str);
+ char c;
+
+ size = min(size, len);
+
+ while (read_pos < size) {
+ c = str[read_pos++];
+ if (c == 0)
+ break;
+ str[write_pos++] = c;
+ if (c == '\n')
+ read_pos += prefix_size;
+ }
+ str[write_pos] = 0;
+}
+
+struct prog_info {
+ char *prog_kind;
+ enum bpf_prog_type prog_type;
+ enum bpf_attach_type expected_attach_type;
+ struct bpf_insn *prog;
+ u32 prog_len;
+};
+
+static void match_program(struct btf *btf,
+ struct prog_info *pinfo,
+ char *pattern,
+ char *reg_map[][2],
+ bool skip_first_insn)
+{
+ struct bpf_insn *buf = NULL;
+ int err = 0, prog_fd = 0;
+ FILE *prog_out = NULL;
+ char *text = NULL;
+ __u32 cnt = 0;
+
+ text = calloc(MAX_PROG_TEXT_SZ, 1);
+ if (!text) {
+ PRINT_FAIL("Can't allocate %d bytes\n", MAX_PROG_TEXT_SZ);
+ goto out;
+ }
+
+ // TODO: log level
+ LIBBPF_OPTS(bpf_prog_load_opts, opts);
+ opts.log_buf = text;
+ opts.log_size = MAX_PROG_TEXT_SZ;
+ opts.log_level = 1 | 2 | 4;
+ opts.expected_attach_type = pinfo->expected_attach_type;
+
+ prog_fd = bpf_prog_load(pinfo->prog_type, NULL, "GPL",
+ pinfo->prog, pinfo->prog_len, &opts);
+ if (prog_fd < 0) {
+ PRINT_FAIL("Can't load program, errno %d (%s), verifier log:\n%s\n",
+ errno, strerror(errno), text);
+ goto out;
+ }
+
+ memset(text, 0, MAX_PROG_TEXT_SZ);
+
+ err = get_xlated_program(prog_fd, &buf, &cnt);
+ if (err) {
+ PRINT_FAIL("Can't load back BPF program\n");
+ goto out;
+ }
+
+ prog_out = fmemopen(text, MAX_PROG_TEXT_SZ - 1, "w");
+ if (!prog_out) {
+ PRINT_FAIL("Can't open memory stream\n");
+ goto out;
+ }
+ if (skip_first_insn)
+ print_xlated(prog_out, buf + 1, cnt - 1);
+ else
+ print_xlated(prog_out, buf, cnt);
+ fclose(prog_out);
+ remove_insn_prefix(text, MAX_PROG_TEXT_SZ);
+
+ ASSERT_TRUE(match_pattern(btf, pattern, text, reg_map),
+ pinfo->prog_kind);
+
+out:
+ if (prog_fd)
+ close(prog_fd);
+ free(buf);
+ free(text);
+}
+
+static void run_one_testcase(struct btf *btf, struct test_case *test)
+{
+ struct prog_info pinfo = {};
+ int bpf_sz;
+
+ if (!test__start_subtest(test->name))
+ return;
+
+ switch (test->field_sz) {
+ case 8:
+ bpf_sz = BPF_DW;
+ break;
+ case 4:
+ bpf_sz = BPF_W;
+ break;
+ case 2:
+ bpf_sz = BPF_H;
+ break;
+ case 1:
+ bpf_sz = BPF_B;
+ break;
+ default:
+ PRINT_FAIL("Unexpected field size: %d, want 8,4,2 or 1\n", test->field_sz);
+ return;
+ }
+
+ pinfo.prog_type = test->prog_type;
+ pinfo.expected_attach_type = test->expected_attach_type;
+
+ if (test->read) {
+ struct bpf_insn ldx_prog[] = {
+ BPF_LDX_MEM(bpf_sz, BPF_REG_2, BPF_REG_1, test->field_offset),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ };
+ char *reg_map[][2] = {
+ { "$ctx", "r1" },
+ { "$dst", "r2" },
+ {}
+ };
+
+ pinfo.prog_kind = "LDX";
+ pinfo.prog = ldx_prog;
+ pinfo.prog_len = ARRAY_SIZE(ldx_prog);
+ match_program(btf, &pinfo, test->read, reg_map, false);
+ }
+
+ if (test->write || test->write_st || test->write_stx) {
+ struct bpf_insn stx_prog[] = {
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_STX_MEM(bpf_sz, BPF_REG_1, BPF_REG_2, test->field_offset),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ };
+ char *stx_reg_map[][2] = {
+ { "$ctx", "r1" },
+ { "$src", "r2" },
+ {}
+ };
+ struct bpf_insn st_prog[] = {
+ BPF_ST_MEM(bpf_sz, BPF_REG_1, test->field_offset,
+ test->st_value.use ? test->st_value.value : 42),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ };
+ char *st_reg_map[][2] = {
+ { "$ctx", "r1" },
+ { "$src", "42" },
+ {}
+ };
+
+ if (test->write || test->write_stx) {
+ char *pattern = test->write_stx ? test->write_stx : test->write;
+
+ pinfo.prog_kind = "STX";
+ pinfo.prog = stx_prog;
+ pinfo.prog_len = ARRAY_SIZE(stx_prog);
+ match_program(btf, &pinfo, pattern, stx_reg_map, true);
+ }
+
+ if (test->write || test->write_st) {
+ char *pattern = test->write_st ? test->write_st : test->write;
+
+ pinfo.prog_kind = "ST";
+ pinfo.prog = st_prog;
+ pinfo.prog_len = ARRAY_SIZE(st_prog);
+ match_program(btf, &pinfo, pattern, st_reg_map, false);
+ }
+ }
+
+ test__end_subtest();
+}
+
+void test_ctx_rewrite(void)
+{
+ struct btf *btf;
+ int i;
+
+ field_regex = compile_regex("^([[:alpha:]_][[:alnum:]_]+)::([[:alpha:]_][[:alnum:]_]+)");
+ ident_regex = compile_regex("^[[:alpha:]_][[:alnum:]_]+");
+ if (!field_regex || !ident_regex)
+ return;
+
+ btf = btf__load_vmlinux_btf();
+ if (!btf) {
+ PRINT_FAIL("Can't load vmlinux BTF, errno %d (%s)\n", errno, strerror(errno));
+ goto out;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(test_cases); ++i)
+ run_one_testcase(btf, &test_cases[i]);
+
+out:
+ btf__free(btf);
+ free_regex(field_regex);
+ free_regex(ident_regex);
+}
projects / users / hch / configfs.git / commitdiff