[PATCH bpf-next] bpf, arm32: Reject BPF_PSEUDO_CALL in the JIT

[bot+bpf-ci at kernel.org]

> Fixes: 1c2a088a6626 ("bpf: x64: add JIT support for multi-function programs")

Is this the correct Fixes tag? That commit only modified x64 JIT code
and BPF core infrastructure for BPF-to-BPF calls - it never touched
arch/arm/net/bpf_jit_32.c.

The actual bug was introduced by commit 39c13c204bb1 ("arm: eBPF JIT
compiler") from August 2017, which added the ARM32 eBPF JIT with
BPF_CALL handling but failed to reject BPF_PSEUDO_CALL. The code has
been incorrectly computing function addresses as 'func = __bpf_call_base
+ imm' for BPF_PSEUDO_CALL since the ARM32 JIT was first introduced.

Suggested: Fixes: 39c13c204bb1 ("arm: eBPF JIT compiler")

> diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
> index deeb8f292454..91fef10e88bc 100644
> --- a/arch/arm/net/bpf_jit_32.c
> +++ b/arch/arm/net/bpf_jit_32.c
> @@ -2047,6 +2047,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
>  	/* function call */
>  	case BPF_JMP | BPF_CALL:
>  	{
> +		if (insn->src_reg == BPF_PSEUDO_CALL)
> +			goto notyet;
>  		const s8 *r0 = bpf2a32[BPF_REG_0];
>  		const s8 *r1 = bpf2a32[BPF_REG_1];
>  		const s8 *r2 = bpf2a32[BPF_REG_2];


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