| 1 | // SPDX-License-Identifier: GPL-2.0 |
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| 2 | /* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */ |
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| 3 | |
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| 4 | #include "vmlinux.h" |
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| 5 | |
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| 6 | #include <string.h> |
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| 7 | #include <bpf/bpf_helpers.h> |
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| 8 | #include <bpf/bpf_core_read.h> |
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| 9 | #include "bpf_kfuncs.h" |
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| 10 | |
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| 11 | __u8 SERVUN_REWRITE_ADDRESS[] = "\0bpf_cgroup_unix_test_rewrite" ; |
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| 12 | |
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| 13 | SEC("cgroup/sendmsg_unix" ) |
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| 14 | int sendmsg_unix_prog(struct bpf_sock_addr *ctx) |
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| 15 | { |
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| 16 | struct bpf_sock_addr_kern *sa_kern = bpf_cast_to_kern_ctx(ctx); |
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| 17 | struct sockaddr_un *sa_kern_unaddr; |
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| 18 | __u32 unaddrlen = offsetof(struct sockaddr_un, sun_path) + |
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| 19 | sizeof(SERVUN_REWRITE_ADDRESS) - 1; |
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| 20 | int ret; |
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| 21 | |
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| 22 | /* Rewrite destination. */ |
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| 23 | ret = bpf_sock_addr_set_sun_path(sa_kern, SERVUN_REWRITE_ADDRESS, |
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| 24 | sizeof(SERVUN_REWRITE_ADDRESS) - 1); |
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| 25 | if (ret) |
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| 26 | return 0; |
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| 27 | |
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| 28 | if (sa_kern->uaddrlen != unaddrlen) |
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| 29 | return 0; |
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| 30 | |
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| 31 | sa_kern_unaddr = bpf_core_cast(sa_kern->uaddr, struct sockaddr_un); |
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| 32 | if (memcmp(sa_kern_unaddr->sun_path, SERVUN_REWRITE_ADDRESS, |
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| 33 | sizeof(SERVUN_REWRITE_ADDRESS) - 1) != 0) |
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| 34 | return 0; |
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| 35 | |
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| 36 | return 1; |
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| 37 | } |
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| 38 | |
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| 39 | char _license[] SEC("license" ) = "GPL" ; |
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| 40 | |
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