Merge branch 'bpf-fix-verifier-crash-on-bpf_neg-with-pointer-register'

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Brahmajit Das says:

====================
bpf: Fix verifier crash on BPF_NEG with pointer register

This patch fixes a crash in the BPF verifier triggered when the BPF_NEG
operation is applied to a pointer-typed register. The verifier now
checks that the destination register is not a pointer before performing
the operation.

Tested with syzkaller reproducer and new BPF sefltest.
Closes: https://syzkaller.appspot.com/bug?extid=d36d5ae81e1b0a53ef58

Changes v4:
Cleaning up, instead of using __is_pointer_value it's further
simplified by checking if regs[insn->dst_reg].type of SCALAR_VALUE
Link:

Changes in v3:
using __is_pointer_value to check if register if of pointer type
Link: https://lore.kernel.org/all/20251001095613.267475-1-listout@listout.xyz/

Changes in v2:
Checking if reg->map_ptr is NULL in bpf/log.c but with cleaner approach
(wrong approach)
Link: https://lore.kernel.org/all/20250923174738.1713751-1-listout@listout.xyz/

Changes in v1:
Checking if reg->map_ptr is NULL in bpf/log.c (wrong approach)
Link: https://lore.kernel.org/all/20250923164144.1573636-1-listout@listout.xyz/
====================

Link: https://patch.msgid.link/20251001191739.2323644-1-listout@listout.xyz
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

...

This commit is contained in:

Alexei Starovoitov 2025-10-01 13:53:20 -07:00

parent 0c342bfc99 8709c16852

commit a1aca22d26

2 changed files with 20 additions and 1 deletions

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3

kernel/bpf/verifier.c

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18

tools/testing/selftests/bpf/progs/verifier_value_illegal_alu.c

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