From 836b2fe544a5e9b5ce116622cb36fba33838c6fd Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Fri, 4 Sep 2026 01:33:23 -0700 Subject: selftests/bpf: Check that JMP32 pointer vs zero jumps are not predicted Add jmp32_ptr_vs_zero_jne: the fall-through of the 32-bit compare, which the verifier used to skip, contains an out of bounds map value access, hence w/o the previous patch the program is accepted. See previous patch for detailed description. Reported-by: Nicholas Carlini Suggested-by: Nicholas Carlini Signed-off-by: Eduard Zingerman Link: https://lore.kernel.org/bpf/20260904083325.2083493-6-eddyz87@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi --- include/asm-generic/fprobe.h | 46 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 include/asm-generic/fprobe.h (limited to 'include/asm-generic/fprobe.h') diff --git a/include/asm-generic/fprobe.h b/include/asm-generic/fprobe.h new file mode 100644 index 000000000..8659a4dc6 --- /dev/null +++ b/include/asm-generic/fprobe.h @@ -0,0 +1,46 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Generic arch dependent fprobe macros. + */ +#ifndef __ASM_GENERIC_FPROBE_H__ +#define __ASM_GENERIC_FPROBE_H__ + +#include + +#ifdef CONFIG_64BIT +/* + * Encoding the size and the address of fprobe into one 64bit entry. + * The 32bit architectures should use 2 entries to store those info. + */ + +#define ARCH_DEFINE_ENCODE_FPROBE_HEADER + +#define FPROBE_HEADER_MSB_SIZE_SHIFT (BITS_PER_LONG - FPROBE_DATA_SIZE_BITS) +#define FPROBE_HEADER_MSB_MASK \ + GENMASK(FPROBE_HEADER_MSB_SIZE_SHIFT - 1, 0) + +/* + * By default, this expects the MSBs in the address of kprobe is 0xf. + * If any arch needs another fixed pattern (e.g. s390 is zero filled), + * override this. + */ +#define FPROBE_HEADER_MSB_PATTERN \ + GENMASK(BITS_PER_LONG - 1, FPROBE_HEADER_MSB_SIZE_SHIFT) + +#define arch_fprobe_header_encodable(fp) \ + (((unsigned long)(fp) & ~FPROBE_HEADER_MSB_MASK) == \ + FPROBE_HEADER_MSB_PATTERN) + +#define arch_encode_fprobe_header(fp, size) \ + (((unsigned long)(fp) & FPROBE_HEADER_MSB_MASK) | \ + ((unsigned long)(size) << FPROBE_HEADER_MSB_SIZE_SHIFT)) + +#define arch_decode_fprobe_header_size(val) \ + ((unsigned long)(val) >> FPROBE_HEADER_MSB_SIZE_SHIFT) + +#define arch_decode_fprobe_header_fp(val) \ + ((struct fprobe *)(((unsigned long)(val) & FPROBE_HEADER_MSB_MASK) | \ + FPROBE_HEADER_MSB_PATTERN)) +#endif /* CONFIG_64BIT */ + +#endif /* __ASM_GENERIC_FPROBE_H__ */ -- cgit v1.3.1