| Message ID | 20240712080127.136608-1-shung-hsi.yu@suse.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Use overflow.h helpers to check for overflows | expand |
Hello: This series was applied to bpf/bpf-next.git (master) by Alexei Starovoitov <ast@kernel.org>: On Fri, 12 Jul 2024 16:01:23 +0800 you wrote: > This patch set refactors kernel/bpf/verifier.c to use type-agnostic, generic > overflow-check helpers defined in include/linux/overflow.h to check for addition > and subtraction overflow, and drop the signed_*_overflows() helpers we currently > have in kernel/bpf/verifier.c; with a fix for overflow check in adjust_jmp_off() > in patch 1. > > There should be no functional change in how the verifier works and the main > motivation is to make future refactoring[1] easier. > > [...] Here is the summary with links: - [bpf-next,v3,1/3] bpf: fix overflow check in adjust_jmp_off() https://git.kernel.org/bpf/bpf-next/c/4a04b4f0de59 - [bpf-next,v3,2/3] bpf: use check_add_overflow() to check for addition overflows https://git.kernel.org/bpf/bpf-next/c/28a4411076b2 - [bpf-next,v3,3/3] bpf: use check_sub_overflow() to check for subtraction overflows https://git.kernel.org/bpf/bpf-next/c/deac5871eb07 You are awesome, thank you!
This patch set refactors kernel/bpf/verifier.c to use type-agnostic, generic overflow-check helpers defined in include/linux/overflow.h to check for addition and subtraction overflow, and drop the signed_*_overflows() helpers we currently have in kernel/bpf/verifier.c; with a fix for overflow check in adjust_jmp_off() in patch 1. There should be no functional change in how the verifier works and the main motivation is to make future refactoring[1] easier. While check_mul_overflow() also exists and could potentially replace what we have in scalar*_min_max_mul(), it does not help with refactoring and would either change how the verifier works (e.g. lifting restriction on umax<=U32_MAX and u32_max<=U16_MAX) or make the code slightly harder to read, so it is left for future endeavour. Changes from v2 <https://lore.kernel.org/r/20240701055907.82481-1-shung-hsi.yu@suse.com> - add fix for 5337ac4c9b80 ("bpf: Fix the corner case with may_goto and jump to the 1st insn.") to correct the overflow check for general jump instructions - adapt to changes in commit 5337ac4c9b80 ("bpf: Fix the corner case with may_goto and jump to the 1st insn.") - refactor in adjust_jmp_off() as well and remove signed_add16_overflow() Changes from v1 <https://lore.kernel.org/r/20240623070324.12634-1-shung-hsi.yu@suse.com>: - use pointers to values in dst_reg directly as the sum/diff pointer and remove the else branch (Jiri) - change local variables to be dst_reg pointers instead of src_reg values - include comparison of generated assembly before & after the change (Alexei) 1: https://github.com/kernel-patches/bpf/pull/7205/commits Shung-Hsi Yu (3): bpf: fix overflow check in adjust_jmp_off() bpf: use check_add_overflow() to check for addition overflows bpf: use check_sub_overflow() to check for subtraction overflows kernel/bpf/verifier.c | 171 ++++++++++++------------------------------ 1 file changed, 48 insertions(+), 123 deletions(-)