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f8b19aeca1
Add selftest cases that validate bpftool's expected behavior when accessing maps protected from modification via security_bpf_map. The test includes a BPF program attached to security_bpf_map with two maps: - A protected map that only allows read-only access - An unprotected map that allows full access The test script attaches the BPF program to security_bpf_map and verifies that for the bpftool map command: - Read access works on both maps - Write access fails on the protected map - Write access succeeds on the unprotected map - These behaviors remain consistent when the maps are pinned Signed-off-by: Slava Imameev <slava.imameev@crowdstrike.com> Reviewed-by: Quentin Monnet <qmo@kernel.org> Link: https://lore.kernel.org/r/20250620151812.13952-2-slava.imameev@crowdstrike.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
69 lines
1.4 KiB
C
69 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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#include "vmlinux.h"
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#include <bpf/bpf_tracing.h>
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#include <bpf/bpf_helpers.h>
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char _license[] SEC("license") = "GPL";
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#define EPERM 1 /* Operation not permitted */
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/* From include/linux/mm.h. */
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#define FMODE_WRITE 0x2
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struct map;
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__type(key, __u32);
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__type(value, __u32);
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__uint(max_entries, 1);
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} prot_status_map SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__type(key, __u32);
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__type(value, __u32);
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__uint(max_entries, 3);
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} prot_map SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__type(key, __u32);
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__type(value, __u32);
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__uint(max_entries, 3);
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} not_prot_map SEC(".maps");
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SEC("fmod_ret/security_bpf_map")
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int BPF_PROG(fmod_bpf_map, struct bpf_map *map, int fmode)
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{
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__u32 key = 0;
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__u32 *status_ptr = bpf_map_lookup_elem(&prot_status_map, &key);
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if (!status_ptr || !*status_ptr)
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return 0;
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if (map == &prot_map) {
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/* Allow read-only access */
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if (fmode & FMODE_WRITE)
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return -EPERM;
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}
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return 0;
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}
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/*
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* This program keeps references to maps. This is needed to prevent
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* optimizing them out.
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*/
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SEC("fentry/bpf_fentry_test1")
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int BPF_PROG(fentry_dummy1, int a)
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{
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__u32 key = 0;
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__u32 val1 = a;
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__u32 val2 = a + 1;
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bpf_map_update_elem(&prot_map, &key, &val1, BPF_ANY);
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bpf_map_update_elem(¬_prot_map, &key, &val2, BPF_ANY);
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return 0;
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}
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