[PATCH bpf-next v1 0/4] Allow variable offsets for syscall PTR_TO_CTX

[Kumar Kartikeya Dwivedi <memxor@gmail.com>]

Enable pointer modification with variable offsets accumulated in the
register for PTR_TO_CTX for syscall programs where it won't be
rewritten, and the context is user-supplied and checked against the max
offset. See patches for details. Fixed offset support landed in [0].

By combining this set with [0], examples like the one below should
succeed verification.

  SEC("syscall")
  int prog(void *ctx) {
	int *arr = ctx;
	int i;

	bpf_for(i, 0, 100)
		arr[i] *= i;

	return 0;
  }

  [0]: https://lore.kernel.org/bpf/20260227005725.1247305-1-memxor@gmail.com

Kumar Kartikeya Dwivedi (4):
  bpf: Support variable offsets for syscall PTR_TO_CTX
  selftests/bpf: Adjust syscall ctx variable offset tests
  bpf: Reject modified syscall PTR_TO_CTX for global subprogs
  selftests/bpf: Test modified syscall ctx for global subprog

 kernel/bpf/verifier.c                         |  62 ++-
 .../selftests/bpf/prog_tests/verifier.c       |  34 +-
 .../selftests/bpf/progs/verifier_ctx.c        | 356 +++++++++++++++---
 .../bpf/progs/verifier_global_subprogs.c      |  43 ++-
 .../selftests/bpf/test_kmods/bpf_testmod.c    |   2 +-
 5 files changed, 409 insertions(+), 88 deletions(-)


base-commit: 2364959abecb052d7b798ae51d0626edec8b9288
-- 
2.52.0