Make the verifier sanitize LDX insns in jited BPF programs. Saved
all the scratch regs to the extended stack first, skip backing up
of R0 if it is the dst_reg, then save checking addr to R1. Finally
the checking funcs are inserted, and regs are restored then.
Signed-off-by: Hao Sun <sunhao.th@xxxxxxxxx>
---
kernel/bpf/verifier.c | 60 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 60 insertions(+)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 7a31fceee370..b3b6855a9756 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -15345,6 +15345,18 @@ BPF_ASAN_STORE(16);
BPF_ASAN_STORE(32);
BPF_ASAN_STORE(64);
+#define BPF_ASAN_LOAD(n) \
+ notrace u64 bpf_asan_load##n(u##n *addr); \
+ notrace u64 bpf_asan_load##n(u##n *addr) \
+ { \
+ return *addr; \
+ }
+
+BPF_ASAN_LOAD(8);
+BPF_ASAN_LOAD(16);
+BPF_ASAN_LOAD(32);
+BPF_ASAN_LOAD(64);
+
#endif
/* Do various post-verification rewrites in a single program pass.
@@ -15567,6 +15579,54 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
insn = new_prog->insnsi + i + delta;
continue;
}
+
+ /* Sanitize LDX operation*/
+ if (BPF_CLASS(insn->code) == BPF_LDX) {
+ struct bpf_insn sanitize_fn;
+ struct bpf_insn *patch = &insn_buf[0];
+
+ if (in_patch_use_ax || insn->src_reg == BPF_REG_10)
+ continue;
+
+ switch (BPF_SIZE(insn->code)) {
+ case BPF_B:
+ sanitize_fn = BPF_EMIT_CALL(bpf_asan_load8);
+ break;
+ case BPF_H:
+ sanitize_fn = BPF_EMIT_CALL(bpf_asan_load16);
+ break;
+ case BPF_W:
+ sanitize_fn = BPF_EMIT_CALL(bpf_asan_load32);
+ break;
+ case BPF_DW:
+ sanitize_fn = BPF_EMIT_CALL(bpf_asan_load64);
+ break;
+ }
+
+ BACKUP_SCRATCH_REGS;
+ /* Skip R0, if it is dst but not src */
+ if (insn->dst_reg != BPF_REG_0 || insn->src_reg == BPF_REG_0)
+ *patch++ = BPF_MOV64_REG(BPF_REG_AX, BPF_REG_0);
+ if (insn->src_reg != BPF_REG_1)
+ *patch++ = BPF_MOV64_REG(BPF_REG_1, insn->src_reg);
+ if (insn->off != 0)
+ *patch++ = BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, insn->off);
+ *patch++ = sanitize_fn;
+ RESTORE_SCRATCH_REGS;
+ if (insn->dst_reg != BPF_REG_0 || insn->src_reg == BPF_REG_0)
+ *patch++ = BPF_MOV64_REG(BPF_REG_0, BPF_REG_AX);
+ *patch++ = *insn;
+ cnt = patch - insn_buf;
+
+ new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+ env->prog = prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ continue;
+ }
#endif
if (insn->code != (BPF_JMP | BPF_CALL))
--
2.38.1
