bpf: Switch BPF probe insns to bpf_probe_read_kernel (6e07a634) · Commits · 戴 / test

Commit ("bpf: Add support for BTF pointers to interpreter") explicitly states that the pointer to BTF object is a pointer to a kernel object or NULL. Therefore we should also switch to using the strict kernel probe helper which is restricted to kernel addresses only when architectures have non-overlapping address spaces. Signed-off-by:

Daniel Borkmann <daniel@iogearbox.net> Signed-off-by:

Alexei Starovoitov <ast@kernel.org> Acked-by:

Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/d2b90827837685424a4b8008dfe0460558abfada.1572649915.git.daniel@iogearbox.net

kernel/bpf/core.c

+5 −4

Original line number	Original line	Diff line number	Diff line
	@@ -1306,11 +1306,12 @@ bool bpf_opcode_in_insntable(u8 code)
	}		}

	#ifndef CONFIG_BPF_JIT_ALWAYS_ON		#ifndef CONFIG_BPF_JIT_ALWAYS_ON
	u64 __weak bpf_probe_read(void * dst, u32 size, const void * unsafe_ptr)		u64 __weak bpf_probe_read_kernel(void dst, u32 size, const void unsafe_ptr)
	{		{
	memset(dst, 0, size);		memset(dst, 0, size);
	return -EFAULT;		return -EFAULT;
	}		}

	/**		/**
	* __bpf_prog_run - run eBPF program on a given context		* __bpf_prog_run - run eBPF program on a given context
	* @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers		* @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers
	@@ -1568,7 +1569,7 @@ out:
	#undef LDST		#undef LDST
	#define LDX_PROBE(SIZEOP, SIZE) \		#define LDX_PROBE(SIZEOP, SIZE) \
	LDX_PROBE_MEM_##SIZEOP: \		LDX_PROBE_MEM_##SIZEOP: \
	bpf_probe_read(&DST, SIZE, (const void *)(long) SRC); \		bpf_probe_read_kernel(&DST, SIZE, (const void *)(long) SRC); \
	CONT;		CONT;
	LDX_PROBE(B, 1)		LDX_PROBE(B, 1)
	LDX_PROBE(H, 2)		LDX_PROBE(H, 2)

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