diff options
Diffstat (limited to 'tools/testing/selftests/bpf/progs/sockopt_sk.c')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/sockopt_sk.c | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/sockopt_sk.c b/tools/testing/selftests/bpf/progs/sockopt_sk.c new file mode 100644 index 000000000000..076122c898e9 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/sockopt_sk.c @@ -0,0 +1,111 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <netinet/in.h> +#include <linux/bpf.h> +#include "bpf_helpers.h" + +char _license[] SEC("license") = "GPL"; +__u32 _version SEC("version") = 1; + +#define SOL_CUSTOM 0xdeadbeef + +struct sockopt_sk { + __u8 val; +}; + +struct bpf_map_def SEC("maps") socket_storage_map = { + .type = BPF_MAP_TYPE_SK_STORAGE, + .key_size = sizeof(int), + .value_size = sizeof(struct sockopt_sk), + .map_flags = BPF_F_NO_PREALLOC, +}; +BPF_ANNOTATE_KV_PAIR(socket_storage_map, int, struct sockopt_sk); + +SEC("cgroup/getsockopt") +int _getsockopt(struct bpf_sockopt *ctx) +{ + __u8 *optval_end = ctx->optval_end; + __u8 *optval = ctx->optval; + struct sockopt_sk *storage; + + if (ctx->level == SOL_IP && ctx->optname == IP_TOS) + /* Not interested in SOL_IP:IP_TOS; + * let next BPF program in the cgroup chain or kernel + * handle it. + */ + return 1; + + if (ctx->level == SOL_SOCKET && ctx->optname == SO_SNDBUF) { + /* Not interested in SOL_SOCKET:SO_SNDBUF; + * let next BPF program in the cgroup chain or kernel + * handle it. + */ + return 1; + } + + if (ctx->level != SOL_CUSTOM) + return 0; /* EPERM, deny everything except custom level */ + + if (optval + 1 > optval_end) + return 0; /* EPERM, bounds check */ + + storage = bpf_sk_storage_get(&socket_storage_map, ctx->sk, 0, + BPF_SK_STORAGE_GET_F_CREATE); + if (!storage) + return 0; /* EPERM, couldn't get sk storage */ + + if (!ctx->retval) + return 0; /* EPERM, kernel should not have handled + * SOL_CUSTOM, something is wrong! + */ + ctx->retval = 0; /* Reset system call return value to zero */ + + optval[0] = storage->val; + ctx->optlen = 1; + + return 1; +} + +SEC("cgroup/setsockopt") +int _setsockopt(struct bpf_sockopt *ctx) +{ + __u8 *optval_end = ctx->optval_end; + __u8 *optval = ctx->optval; + struct sockopt_sk *storage; + + if (ctx->level == SOL_IP && ctx->optname == IP_TOS) + /* Not interested in SOL_IP:IP_TOS; + * let next BPF program in the cgroup chain or kernel + * handle it. + */ + return 1; + + if (ctx->level == SOL_SOCKET && ctx->optname == SO_SNDBUF) { + /* Overwrite SO_SNDBUF value */ + + if (optval + sizeof(__u32) > optval_end) + return 0; /* EPERM, bounds check */ + + *(__u32 *)optval = 0x55AA; + ctx->optlen = 4; + + return 1; + } + + if (ctx->level != SOL_CUSTOM) + return 0; /* EPERM, deny everything except custom level */ + + if (optval + 1 > optval_end) + return 0; /* EPERM, bounds check */ + + storage = bpf_sk_storage_get(&socket_storage_map, ctx->sk, 0, + BPF_SK_STORAGE_GET_F_CREATE); + if (!storage) + return 0; /* EPERM, couldn't get sk storage */ + + storage->val = optval[0]; + ctx->optlen = -1; /* BPF has consumed this option, don't call kernel + * setsockopt handler. + */ + + return 1; +} |