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
37ad2bb11e
commitee861486e3upstream. Usage of ld_{abs,ind} instructions got extended into subprogs some time ago via commit09b28d76ea("bpf: Add abnormal return checks."). These are only allowed in subprograms when the latter are BTF annotated and have scalar return types. The code generator in bpf_gen_ld_abs() has an abnormal exit path (r0=0 + exit) from legacy cBPF times. While the enforcement is on scalar return types, the verifier must also simulate the path of abnormal exit if the packet data load via ld_{abs,ind} failed. This is currently not the case. Fix it by having the verifier simulate both success and failure paths, and extend it in similar ways as we do for tail calls. The success path (r0=unknown, continue to next insn) is pushed onto stack for later validation and the r0=0 and return to the caller is done on the fall-through side. Fixes:09b28d76ea("bpf: Add abnormal return checks.") Reported-by: STAR Labs SG <info@starlabs.sg> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/r/20260408191242.526279-2-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov <ast@kernel.org> [ Dropped visit_abnormal_return_insn changes: depends on 7.0 symbols frome40f5a6bf8("bpf: correct stack liveness for tail calls"); Hunk1: adapted IS_ERR/PTR_ERR to !branch/-EFAULT to match push_stack() NULL-on-failure convention. ] Signed-off-by: Philo Lu <lulie@linux.alibaba.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 Restructured Text 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.