[PATCH bpf-next v5 0/3] Introduce kfuncs for memory reads into dynptrs

[Mykyta Yatsenko <mykyta.yatsenko5@gmail.com>]

From: Mykyta Yatsenko <yatsenko@meta.com>

This patch adds new kfuncs that enable reading variable-length
user or kernel data directly into dynptrs.
These kfuncs provide a way to perform dynamically-sized reads
while maintaining memory safety. Unlike existing
`bpf_probe_read_{user|kernel}` APIs, which are limited to constant-sized
reads, these new kfuncs allow for more flexible data access.

v4 -> v5
 * Fix pointers annotations, use __user where necessary, cast where needed

v3 -> v4
 * Added pid filtering in selftests

v2 -> v3
 * Add KF_TRUSTED_ARGS for kfuncs that take pointer to task_struct
 as an argument
 * Remove checks for non-NULL task, where it was not necessary
 * Added comments on constants used in selftests, etc.

v1 -> v2
 * Renaming helper functions to use "user_str" instead of "user_data_str"
 suffix
 
Mykyta Yatsenko (3):
  helpers: make few bpf helpers public
  bpf: implement dynptr copy kfuncs
  selftests/bpf: introduce tests for dynptr copy kfuncs

 include/linux/bpf.h                           |  14 ++
 kernel/bpf/helpers.c                          |  22 +-
 kernel/trace/bpf_trace.c                      | 193 +++++++++++++++
 tools/testing/selftests/bpf/DENYLIST          |   1 +
 .../testing/selftests/bpf/prog_tests/dynptr.c |  13 +
 .../selftests/bpf/progs/dynptr_success.c      | 230 ++++++++++++++++++
 6 files changed, 461 insertions(+), 12 deletions(-)

-- 
2.49.0