Andrey Ignatov 5e43f899b0 bpf: Check attach type at prog load time ... == The problem == There are use-cases when a program of some type can be attached to multiple attach points and those attach points must have different permissions to access context or to call helpers. E.g. context structure may have fields for both IPv4 and IPv6 but it doesn't make sense to read from / write to IPv6 field when attach point is somewhere in IPv4 stack. Same applies to BPF-helpers: it may make sense to call some helper from some attach point, but not from other for same prog type. == The solution == Introduce `expected_attach_type` field in in `struct bpf_attr` for `BPF_PROG_LOAD` command. If scenario described in "The problem" section is the case for some prog type, the field will be checked twice: 1) At load time prog type is checked to see if attach type for it must be known to validate program permissions correctly. Prog will be rejected with EINVAL if it's the case and `expected_attach_type` is not specified or has invalid value. 2) At attach time `attach_type` is compared with `expected_attach_type`, if prog type requires to have one, and, if they differ, attach will be rejected with EINVAL. The `expected_attach_type` is now available as part of `struct bpf_prog` in both `bpf_verifier_ops->is_valid_access()` and `bpf_verifier_ops->get_func_proto()` () and can be used to check context accesses and calls to helpers correspondingly. Initially the idea was discussed by Alexei Starovoitov <ast@fb.com> and Daniel Borkmann <daniel@iogearbox.net> here: https://marc.info/?l=linux-netdev&m=152107378717201&w=2 Signed-off-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>		2018-03-31 02:14:44 +02:00
..
arraymap.c	bpf: add schedule points in percpu arrays management	2018-02-22 21:27:06 +01:00
bpf_lru_list.c	bpf: lru: Lower the PERCPU_NR_SCANS from 16 to 4	2017-04-17 13:55:52 -04:00
bpf_lru_list.h	bpf: Only set node->ref = 1 if it has not been set	2017-09-01 09:57:39 -07:00
cgroup.c	bpf: Check attach type at prog load time	2018-03-31 02:14:44 +02:00
core.c	bpf: fix bpf_prog_array_copy_to_user warning from perf event prog query	2018-02-14 08:59:37 -08:00
cpumap.c	bpf: cpumap: use GFP_KERNEL instead of GFP_ATOMIC in __cpu_map_entry_alloc()	2018-02-14 15:34:27 +01:00
devmap.c	bpf: add helper for copying attrs to struct bpf_map	2018-01-14 23:36:29 +01:00
disasm.c	bpf: Remove struct bpf_verifier_env argument from print_bpf_insn	2018-03-23 17:38:57 +01:00
disasm.h	bpf: Remove struct bpf_verifier_env argument from print_bpf_insn	2018-03-23 17:38:57 +01:00
hashtab.c	bpf: add helper for copying attrs to struct bpf_map	2018-01-14 23:36:29 +01:00
helpers.c	bpf: rename ARG_PTR_TO_STACK	2017-01-09 16:56:27 -05:00
inode.c	bpf: comment why dots in filenames under BPF virtual FS are not allowed	2018-03-09 10:30:30 +01:00
lpm_trie.c	bpf: fix rcu lockdep warning for lpm_trie map_free callback	2018-02-22 21:29:12 +01:00
Makefile	bpf: only build sockmap with CONFIG_INET	2018-01-04 19:01:14 +01:00
map_in_map.c	bpf: Add syscall lookup support for fd array and htab	2017-06-29 13:13:25 -04:00
map_in_map.h	bpf: Add syscall lookup support for fd array and htab	2017-06-29 13:13:25 -04:00
offload.c	bpf: offload: report device information about offloaded maps	2018-01-18 22:54:25 +01:00
percpu_freelist.c	bpf: fix lockdep splat	2017-11-15 19:46:32 +09:00
percpu_freelist.h	bpf: introduce percpu_freelist	2016-03-08 15:28:31 -05:00
sockmap.c	bpf: sockmap: initialize sg table entries properly	2018-03-30 22:50:15 +02:00
stackmap.c	bpf: extend stackmap to save binary_build_id+offset instead of address	2018-03-15 01:09:28 +01:00
syscall.c	bpf: Check attach type at prog load time	2018-03-31 02:14:44 +02:00
tnum.c	bpf/verifier: track signed and unsigned min/max values	2017-08-08 17:51:34 -07:00
verifier.c	bpf: Check attach type at prog load time	2018-03-31 02:14:44 +02:00