65 lines
1.4 KiB
C
65 lines
1.4 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
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#include "vmlinux.h"
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#include <errno.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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#include "bpf_kfuncs.h"
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char _license[] SEC("license") = "GPL";
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__u32 monitored_pid;
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__u32 found_xattr_from_file;
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__u32 found_xattr_from_dentry;
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static const char expected_value[] = "hello";
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char value1[32];
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char value2[32];
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SEC("lsm.s/file_open")
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int BPF_PROG(test_file_open, struct file *f)
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{
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struct bpf_dynptr value_ptr;
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__u32 pid;
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int ret;
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pid = bpf_get_current_pid_tgid() >> 32;
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if (pid != monitored_pid)
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return 0;
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bpf_dynptr_from_mem(value1, sizeof(value1), 0, &value_ptr);
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ret = bpf_get_file_xattr(f, "user.kfuncs", &value_ptr);
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if (ret != sizeof(expected_value))
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return 0;
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if (bpf_strncmp(value1, ret, expected_value))
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return 0;
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found_xattr_from_file = 1;
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return 0;
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}
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SEC("lsm.s/inode_getxattr")
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int BPF_PROG(test_inode_getxattr, struct dentry *dentry, char *name)
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{
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struct bpf_dynptr value_ptr;
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__u32 pid;
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int ret;
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pid = bpf_get_current_pid_tgid() >> 32;
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if (pid != monitored_pid)
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return 0;
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bpf_dynptr_from_mem(value2, sizeof(value2), 0, &value_ptr);
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ret = bpf_get_dentry_xattr(dentry, "user.kfuncs", &value_ptr);
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if (ret != sizeof(expected_value))
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return 0;
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if (bpf_strncmp(value2, ret, expected_value))
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return 0;
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found_xattr_from_dentry = 1;
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/* return non-zero to fail getxattr from user space */
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return -EINVAL;
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}
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