mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2026-09-22 09:34:56 +02:00
Daniel Borkmann
d75376fbc8
commit1b327732c8upstream. When a non-{add,sub} alu op such as xor is performed on a scalar register that previously had a BPF_ADD_CONST delta, the else path in adjust_reg_min_max_vals() only clears dst_reg->id but leaves dst_reg->delta unchanged. This stale delta can propagate via assign_scalar_id_before_mov() when the register is later used in a mov. It gets a fresh id but keeps the stale delta from the old (now-cleared) BPF_ADD_CONST. This stale delta can later propagate leading to a verifier-vs- runtime value mismatch. The clear_id label already correctly clears both delta and id. Make the else path consistent by also zeroing the delta when id is cleared. More generally, this introduces a helper clear_scalar_id() which internally takes care of zeroing. There are various other locations in the verifier where only the id is cleared. By using the helper we catch all current and future locations. Fixes:98d7ca374b("bpf: Track delta between "linked" registers.") Reported-by: STAR Labs SG <info@starlabs.sg> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/r/20260407192421.508817-2-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov <ast@kernel.org> [shung-hsi.yu: `delta` field was called `off` before commit3d91c618ac("bpf: rename bpf_reg_state->off to bpf_reg_state->delta"), and clear_singular_ids() does not exists before commitb2a0aa3a87("bpf: Clear singular ids for scalars in is_state_visited()")] Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.