From 33a154a96e71a34a1bcca9f40da343dbbf7b38b4 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Thu, 1 Oct 2026 14:52:55 +0000 Subject: selftests/bpf: Test packet range of pointers sharing an id Add tests where two packet pointers share an id and tightening one pointer's umax from its var_off would put it less than their constant distance from the other's umax: with an index & 0x38 capped at 50, the base pointer keeps umax 50, so the pointer 8 bytes further on must keep umax 58, even though its known bits allow at most 56. These refused a valid program or accepted an out-of-bounds access before the fix: - check the advanced copy, load through the base: valid, was refused; - check the base, load the byte at base + 1 through a copy advanced by 8: was accepted; - check base + 4, load 4 bytes at base + 2 through base + 8: reads two bytes past the checked range, was accepted; - the same as the second with data_meta pointers checked against data: was accepted. These pass with and without the fix and cover nearby paths: - subtract an unknown scalar from a checked pointer and load below it (the range is kept across a new id); - reach a load through two paths whose checks cover 8 and 7 bytes after the loaded pointer; the second path must not be pruned by the first; - spill a copy of a pointer, check the pointer, fill the copy and load one byte past the checked range: the load is refused, and the copy has the range of the check. Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20261001145255.855630-2-alexei.starovoitov@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi --- include/asm-generic/flat.h | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 include/asm-generic/flat.h (limited to 'include/asm-generic/flat.h') diff --git a/include/asm-generic/flat.h b/include/asm-generic/flat.h new file mode 100644 index 000000000..1928a3596 --- /dev/null +++ b/include/asm-generic/flat.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_GENERIC_FLAT_H +#define _ASM_GENERIC_FLAT_H + +#include + +static inline int flat_get_addr_from_rp(u32 __user *rp, u32 relval, u32 flags, + u32 *addr) +{ +#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS + return copy_from_user(addr, rp, 4) ? -EFAULT : 0; +#else + return get_user(*addr, rp); +#endif +} + +static inline int flat_put_addr_at_rp(u32 __user *rp, u32 addr, u32 rel) +{ +#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS + return copy_to_user(rp, &addr, 4) ? -EFAULT : 0; +#else + return put_user(addr, rp); +#endif +} + +#endif /* _ASM_GENERIC_FLAT_H */ -- cgit v1.3.1