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2020-11-06bpf: Update verification logic for LSM programsKP Singh1-3/+7
The current logic checks if the name of the BTF type passed in attach_btf_id starts with "bpf_lsm_", this is not sufficient as it also allows attachment to non-LSM hooks like the very function that performs this check, i.e. bpf_lsm_verify_prog. In order to ensure that this verification logic allows attachment to only LSM hooks, the LSM_HOOK definitions in lsm_hook_defs.h are used to generate a BTF_ID set. Upon verification, the attach_btf_id of the program being attached is checked for presence in this set. Fixes: 9e4e01dfd325 ("bpf: lsm: Implement attach, detach and execution") Signed-off-by: KP Singh <kpsingh@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20201105230651.2621917-1-kpsingh@chromium.org
2020-09-25bpf: Change bpf_sk_storage_*() to accept ARG_PTR_TO_BTF_ID_SOCK_COMMONMartin KaFai Lau1-2/+2
This patch changes the bpf_sk_storage_*() to take ARG_PTR_TO_BTF_ID_SOCK_COMMON such that they will work with the pointer returned by the bpf_skc_to_*() helpers also. A micro benchmark has been done on a "cgroup_skb/egress" bpf program which does a bpf_sk_storage_get(). It was driven by netperf doing a 4096 connected UDP_STREAM test with 64bytes packet. The stats from "kernel.bpf_stats_enabled" shows no meaningful difference. The sk_storage_get_btf_proto, sk_storage_delete_btf_proto, btf_sk_storage_get_proto, and btf_sk_storage_delete_proto are no longer needed, so they are removed. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Lorenz Bauer <lmb@cloudflare.com> Link: https://lore.kernel.org/bpf/20200925000402.3856307-1-kafai@fb.com
2020-08-25bpf: Allow local storage to be used from LSM programsKP Singh1-1/+20
Adds support for both bpf_{sk, inode}_storage_{get, delete} to be used in LSM programs. These helpers are not used for tracing programs (currently) as their usage is tied to the life-cycle of the object and should only be used where the owning object won't be freed (when the owning object is passed as an argument to the LSM hook). Thus, they are safer to use in LSM hooks than tracing. Usage of local storage in tracing programs will probably follow a per function based whitelist approach. Since the UAPI helper signature for bpf_sk_storage expect a bpf_sock, it, leads to a compilation warning for LSM programs, it's also updated to accept a void * pointer instead. Signed-off-by: KP Singh <kpsingh@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200825182919.1118197-7-kpsingh@chromium.org
2020-06-01bpf: Use tracing helpers for lsm programsJiri Olsa1-1/+1
Currenty lsm uses bpf_tracing_func_proto helpers which do not include stack trace or perf event output. It's useful to have those for bpftrace lsm support [1]. Using tracing_prog_func_proto helpers for lsm programs. [1] https://github.com/iovisor/bpftrace/pull/1347 Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Cc: KP Singh <kpsingh@google.com> Link: https://lore.kernel.org/bpf/20200531154255.896551-1-jolsa@kernel.org
2020-03-30bpf: lsm: Implement attach, detach and executionKP Singh1-0/+23
JITed BPF programs are dynamically attached to the LSM hooks using BPF trampolines. The trampoline prologue generates code to handle conversion of the signature of the hook to the appropriate BPF context. The allocated trampoline programs are attached to the nop functions initialized as LSM hooks. BPF_PROG_TYPE_LSM programs must have a GPL compatible license and and need CAP_SYS_ADMIN (required for loading eBPF programs). Upon attachment: * A BPF fexit trampoline is used for LSM hooks with a void return type. * A BPF fmod_ret trampoline is used for LSM hooks which return an int. The attached programs can override the return value of the bpf LSM hook to indicate a MAC Policy decision. Signed-off-by: KP Singh <kpsingh@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Brendan Jackman <jackmanb@google.com> Reviewed-by: Florent Revest <revest@google.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: James Morris <jamorris@linux.microsoft.com> Link: https://lore.kernel.org/bpf/20200329004356.27286-5-kpsingh@chromium.org
2020-03-30bpf: lsm: Provide attachment points for BPF LSM programsKP Singh1-0/+14
When CONFIG_BPF_LSM is enabled, nop functions, bpf_lsm_<hook_name>, are generated for each LSM hook. These functions are initialized as LSM hooks in a subsequent patch. Signed-off-by: KP Singh <kpsingh@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Brendan Jackman <jackmanb@google.com> Reviewed-by: Florent Revest <revest@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: James Morris <jamorris@linux.microsoft.com> Link: https://lore.kernel.org/bpf/20200329004356.27286-4-kpsingh@chromium.org
2020-03-30bpf: Introduce BPF_PROG_TYPE_LSMKP Singh1-0/+17
Introduce types and configs for bpf programs that can be attached to LSM hooks. The programs can be enabled by the config option CONFIG_BPF_LSM. Signed-off-by: KP Singh <kpsingh@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Brendan Jackman <jackmanb@google.com> Reviewed-by: Florent Revest <revest@google.com> Reviewed-by: Thomas Garnier <thgarnie@google.com> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: James Morris <jamorris@linux.microsoft.com> Link: https://lore.kernel.org/bpf/20200329004356.27286-2-kpsingh@chromium.org