From 506ada89629ec7059b96ecfb0dc7d33ece0103ca Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Fri, 4 Sep 2026 17:05:56 -0700 Subject: bpf: mark a NULL kfunc argument precise check_kfunc_arg() allows bpf_register_is_null() for nullable arguments w/o marking the underlying scalar register precise. Hence a checkpoint created on such a path would prune against arbitrary scalar value. Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)") Signed-off-by: Eduard Zingerman Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com Signed-off-by: Alexei Starovoitov --- include/asm-generic/error-injection.h | 43 +++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 include/asm-generic/error-injection.h (limited to 'include/asm-generic/error-injection.h') diff --git a/include/asm-generic/error-injection.h b/include/asm-generic/error-injection.h new file mode 100644 index 000000000..b05253f68 --- /dev/null +++ b/include/asm-generic/error-injection.h @@ -0,0 +1,43 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_GENERIC_ERROR_INJECTION_H +#define _ASM_GENERIC_ERROR_INJECTION_H + +#if defined(__KERNEL__) && !defined(__ASSEMBLY__) +enum { + EI_ETYPE_NULL, /* Return NULL if failure */ + EI_ETYPE_ERRNO, /* Return -ERRNO if failure */ + EI_ETYPE_ERRNO_NULL, /* Return -ERRNO or NULL if failure */ + EI_ETYPE_TRUE, /* Return true if failure */ +}; + +struct error_injection_entry { + unsigned long addr; + int etype; +}; + +struct pt_regs; + +#ifdef CONFIG_FUNCTION_ERROR_INJECTION +/* + * Whitelist generating macro. Specify functions which can be error-injectable + * using this macro. If you unsure what is required for the error-injectable + * functions, please read Documentation/fault-injection/fault-injection.rst + * 'Error Injectable Functions' section. + */ +#define ALLOW_ERROR_INJECTION(fname, _etype) \ +static struct error_injection_entry __used \ + __section("_error_injection_whitelist") \ + _eil_addr_##fname = { \ + .addr = (unsigned long)fname, \ + .etype = EI_ETYPE_##_etype, \ + } + +void override_function_with_return(struct pt_regs *regs); +#else +#define ALLOW_ERROR_INJECTION(fname, _etype) + +static inline void override_function_with_return(struct pt_regs *regs) { } +#endif +#endif + +#endif /* _ASM_GENERIC_ERROR_INJECTION_H */ -- cgit v1.3.1