Bpftool helpers fix#11384
Closed
theihor wants to merge 6 commits intokernel-patches:bpf-next_basefrom
Closed
Conversation
When a register undergoes a BPF_END (byte swap) operation, its scalar value is mutated in-place. If this register previously shared a scalar ID with another register (e.g., after an `r1 = r0` assignment), this tie must be broken. Currently, the verifier misses resetting `dst_reg->id` to 0 for BPF_END. Consequently, if a conditional jump checks the swapped register, the verifier incorrectly propagates the learned bounds to the linked register, leading to false confidence in the linked register's value and potentially allowing out-of-bounds memory accesses. Fix this by explicitly resetting `dst_reg->id` to 0 in the BPF_END case to break the scalar tie, similar to how BPF_NEG handles it via `__mark_reg_known`. Fixes: 9d21199 ("bpf: Add bitwise tracking for BPF_END") Closes: https://lore.kernel.org/bpf/AMBPR06MB108683CFEB1CB8D9E02FC95ECF17EA@AMBPR06MB10868.eurprd06.prod.outlook.com/ Link: https://lore.kernel.org/bpf/4be25f7442a52244d0dd1abb47bc6750e57984c9.camel@gmail.com/ Reported-by: Guillaume Laporte <glapt.pro@outlook.com> Co-developed-by: Tianci Cao <ziye@zju.edu.cn> Signed-off-by: Tianci Cao <ziye@zju.edu.cn> Co-developed-by: Shenghao Yuan <shenghaoyuan0928@163.com> Signed-off-by: Shenghao Yuan <shenghaoyuan0928@163.com> Signed-off-by: Yazhou Tang <tangyazhou518@outlook.com> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/r/20260304083228.142016-2-tangyazhou@zju.edu.cn Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add a test case to ensure that BPF_END operations correctly break register's scalar ID ties. The test creates a scenario where r1 is a copy of r0, r0 undergoes a byte swap, and then r0 is checked against a constant. - Without the fix in the verifier, the bounds learned from r0 are incorrectly propagated to r1, making the verifier believe r1 is bounded and wrongly allowing subsequent pointer arithmetic. - With the fix, r1 remains an unbounded scalar, and the verifier correctly rejects the arithmetic operation between the frame pointer and the unbounded register. Co-developed-by: Tianci Cao <ziye@zju.edu.cn> Signed-off-by: Tianci Cao <ziye@zju.edu.cn> Co-developed-by: Shenghao Yuan <shenghaoyuan0928@163.com> Signed-off-by: Shenghao Yuan <shenghaoyuan0928@163.com> Signed-off-by: Yazhou Tang <tangyazhou518@outlook.com> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/r/20260304083228.142016-3-tangyazhou@zju.edu.cn Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Yazhou Tang says: ==================== bpf: Reset register ID for BPF_END value tracking This patchset fixes a register's scalar ID issue for BPF_END operations reported by Guillaume Laporte. Please see commit log of 1/2 for more details. Changes v1 => v2: 1. Reset register ID inside scalar_byte_swap() conditionally. (Eduard) v1: https://lore.kernel.org/bpf/20260303093956.395076-1-tangyazhou@zju.edu.cn/ ==================== Link: https://patch.msgid.link/20260304083228.142016-1-tangyazhou@zju.edu.cn Signed-off-by: Alexei Starovoitov <ast@kernel.org>
BPF_ST | BPF_PROBE_MEM32 immediate stores are not handled by bpf_jit_blind_insn(), allowing user-controlled 32-bit immediates to survive unblinded into JIT-compiled native code when bpf_jit_harden >= 1. The root cause is that convert_ctx_accesses() rewrites BPF_ST|BPF_MEM to BPF_ST|BPF_PROBE_MEM32 for arena pointer stores during verification, before bpf_jit_blind_constants() runs during JIT compilation. The blinding switch only matches BPF_ST|BPF_MEM (mode 0x60), not BPF_ST|BPF_PROBE_MEM32 (mode 0xa0). The instruction falls through unblinded. Add BPF_ST|BPF_PROBE_MEM32 cases to bpf_jit_blind_insn() alongside the existing BPF_ST|BPF_MEM cases. The blinding transformation is identical: load the blinded immediate into BPF_REG_AX via mov+xor, then convert the immediate store to a register store (BPF_STX). The rewritten STX instruction must preserve the BPF_PROBE_MEM32 mode so the architecture JIT emits the correct arena addressing (R12-based on x86-64). Cannot use the BPF_STX_MEM() macro here because it hardcodes BPF_MEM mode; construct the instruction directly instead. Fixes: 6082b6c ("bpf: Recognize addr_space_cast instruction in the verifier.") Reviewed-by: Puranjay Mohan <puranjay@kernel.org> Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com> Signed-off-by: Sachin Kumar <xcyfun@protonmail.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/r/Y6IT5VvNRchPBLI5D7JZHBzZrU9rb0ycRJPJzJSXGj7kJlX8RJwZFSM2YZjcDxoQKABkxt1T8Os2gi23PYyFuQe6KkZGWVyfz8K5afdy9ak=@protonmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
For commit b0dcdcb ("resolve_btfids: Fix linker flags detection"), I suggested setting HOSTPKG_CONFIG to $PKG_CONFIG when compiling resolve_btfids, but I forgot the quotes around that variable. As a result, when running vmtest.sh with static linking, it fails as follows: $ LDLIBS=-static PKG_CONFIG='pkg-config --static' ./vmtest.sh [...] make: unrecognized option '--static' Usage: make [options] [target] ... [...] This worked when I tested it because HOSTPKG_CONFIG didn't have a default value in the resolve_btfids Makefile, but once it does, the quotes aren't preserved and it fails on the next make call. Fixes: b0dcdcb ("resolve_btfids: Fix linker flags detection") Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com> Acked-by: Mykyta Yatsenko <yatsenko@meta.com> Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev> Link: https://lore.kernel.org/r/abADBwn_ykblpABE@mail.gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
theihor
force-pushed
the
bpftool-helpers-fix
branch
from
8b6db30 to
ecacb16
Compare
kernel-patches-daemon-bpf
Bot
force-pushed
the
bpf-next_base
branch
6 times, most recently
from
1e267ee to
52ba927
Compare
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
No description provided.