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969fb456ff
Add a test that loads an XDP program with a global subprogram using a BPF token from a user namespace, then verifies that both the main program and the subprogram appear in /proc/kallsyms. This exercises the bpf_prog_kallsyms_add() path for subprograms and would have caught the missing aux->token copy in bpf_jit_subprogs(). load_kallsyms_local() filters out kallsyms with zero addresses. For a process with limited capabilities to read kallsym addresses the following sysctl variables have to be set to zero: - /proc/sys/kernel/perf_event_paranoid - /proc/sys/kernel/kptr_restrict Set these variables using sysctl_set() utility function extracted from unpriv_bpf_disabled.c to a separate c/header. Since the test modifies global system state, mark it as serial. Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/r/20260415-subprog-token-fix-v4-2-9bd000e8b068@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
38 lines
805 B
C
38 lines
805 B
C
// SPDX-License-Identifier: GPL-2.0
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#include <stdio.h>
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#include <errno.h>
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#include <string.h>
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#include "sysctl_helpers.h"
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#include "test_progs.h"
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int sysctl_set(const char *sysctl_path, char *old_val, const char *new_val)
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{
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int ret = 0;
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FILE *fp;
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fp = fopen(sysctl_path, "r+");
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if (!fp)
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return -errno;
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if (old_val && fscanf(fp, "%s", old_val) <= 0) {
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ret = -ENOENT;
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} else if (!old_val || strcmp(old_val, new_val) != 0) {
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fseek(fp, 0, SEEK_SET);
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if (fprintf(fp, "%s", new_val) < 0)
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ret = -errno;
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}
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fclose(fp);
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return ret;
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}
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int sysctl_set_or_fail(const char *sysctl_path, char *old_val, const char *new_val)
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{
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int err;
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err = sysctl_set(sysctl_path, old_val, new_val);
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if (err)
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PRINT_FAIL("failed to set %s to %s: %s\n", sysctl_path, new_val, strerror(-err));
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return err;
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}
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