0ba971511d
Add enforcement of expected types for context arguments tagged with arg:ctx (__arg_ctx) tag. First, any program type will accept generic `void *` context type when combined with __arg_ctx tag. Besides accepting "canonical" struct names and `void *`, for a bunch of program types for which program context is actually a named struct, we allows a bunch of pragmatic exceptions to match real-world and expected usage: - for both kprobes and perf_event we allow `bpf_user_pt_regs_t *` as canonical context argument type, where `bpf_user_pt_regs_t` is a *typedef*, not a struct; - for kprobes, we also always accept `struct pt_regs *`, as that's what actually is passed as a context to any kprobe program; - for perf_event, we resolve typedefs (unless it's `bpf_user_pt_regs_t`) down to actual struct type and accept `struct pt_regs *`, or `struct user_pt_regs *`, or `struct user_regs_struct *`, depending on the actual struct type kernel architecture points `bpf_user_pt_regs_t` typedef to; otherwise, canonical `struct bpf_perf_event_data *` is expected; - for raw_tp/raw_tp.w programs, `u64/long *` are accepted, as that's what's expected with BPF_PROG() usage; otherwise, canonical `struct bpf_raw_tracepoint_args *` is expected; - tp_btf supports both `struct bpf_raw_tracepoint_args *` and `u64 *` formats, both are coded as expections as tp_btf is actually a TRACING program type, which has no canonical context type; - iterator programs accept `struct bpf_iter__xxx *` structs, currently with no further iterator-type specific enforcement; - fentry/fexit/fmod_ret/lsm/struct_ops all accept `u64 *`; - classic tracepoint programs, as well as syscall and freplace programs allow any user-provided type. In all other cases kernel will enforce exact match of struct name to expected canonical type. And if user-provided type doesn't match that expectation, verifier will emit helpful message with expected type name. Note a bit unnatural way the check is done after processing all the arguments. This is done to avoid conflict between bpf and bpf-next trees. Once trees converge, a small follow up patch will place a simple btf_validate_prog_ctx_type() check into a proper ARG_PTR_TO_CTX branch (which bpf-next tree patch refactored already), removing duplicated arg:ctx detection logic. Suggested-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20240118033143.3384355-4-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> |
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.. | ||
preload | ||
arraymap.c | ||
bloom_filter.c | ||
bpf_cgrp_storage.c | ||
bpf_inode_storage.c | ||
bpf_iter.c | ||
bpf_local_storage.c | ||
bpf_lru_list.c | ||
bpf_lru_list.h | ||
bpf_lsm.c | ||
bpf_struct_ops_types.h | ||
bpf_struct_ops.c | ||
bpf_task_storage.c | ||
btf.c | ||
cgroup_iter.c | ||
cgroup.c | ||
core.c | ||
cpumap.c | ||
cpumask.c | ||
devmap.c | ||
disasm.c | ||
disasm.h | ||
dispatcher.c | ||
hashtab.c | ||
helpers.c | ||
inode.c | ||
Kconfig | ||
link_iter.c | ||
local_storage.c | ||
log.c | ||
lpm_trie.c | ||
Makefile | ||
map_in_map.c | ||
map_in_map.h | ||
map_iter.c | ||
memalloc.c | ||
mmap_unlock_work.h | ||
mprog.c | ||
net_namespace.c | ||
offload.c | ||
percpu_freelist.c | ||
percpu_freelist.h | ||
prog_iter.c | ||
queue_stack_maps.c | ||
reuseport_array.c | ||
ringbuf.c | ||
stackmap.c | ||
syscall.c | ||
sysfs_btf.c | ||
task_iter.c | ||
tcx.c | ||
tnum.c | ||
trampoline.c | ||
verifier.c |