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bpf: Mask pseudo pointer values in verifier logs

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print_bpf_insn() masks ldimm64 immediates for pointer-bearing pseudo
sources when pointer leaks are not allowed, but the mask only covers
BPF_PSEUDO_MAP_FD and BPF_PSEUDO_MAP_VALUE.

BPF_PSEUDO_MAP_IDX, BPF_PSEUDO_MAP_IDX_VALUE, and BPF_PSEUDO_BTF_ID can
also be resolved to kernel pointer values before the verifier log prints
the instruction. Include them in the existing pointer classification so
the log prints 0x0 instead of the rewritten address.

Fixes: 4976b718c3 ("bpf: Introduce pseudo_btf_id")
Fixes: 387544bfa2 ("bpf: Introduce fd_idx")
Signed-off-by: Nuoqi Gui <gnq25@mails.tsinghua.edu.cn>
Link: https://lore.kernel.org/r/20260623-f01-13-pseudo-btf-id-cap-bpf-v2-1-a190ebb8f3e2@mails.tsinghua.edu.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
This commit is contained in:
Nuoqi Gui
2026-06-23 18:43:38 +08:00
committed by Alexei Starovoitov
parent fbc10dff78
commit 72a85e9464
1 changed files with 4 additions and 1 deletions
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5
kernel/bpf/disasm.c
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@@ -323,7 +323,10 @@ void print_bpf_insn(const struct bpf_insn_cbs *cbs,
*/
u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
bool is_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD ||
insn->src_reg == BPF_PSEUDO_MAP_VALUE;
insn->src_reg == BPF_PSEUDO_MAP_VALUE ||
insn->src_reg == BPF_PSEUDO_MAP_IDX ||
insn->src_reg == BPF_PSEUDO_MAP_IDX_VALUE ||
insn->src_reg == BPF_PSEUDO_BTF_ID;
char tmp[64];
if (is_ptr && !allow_ptr_leaks)