Commit 2a02759ef5f8 ("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@xxxxxxxxxxxxx>
---
kernel/bpf/core.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 673f5d40a93e..76452326fd8e 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -1309,11 +1309,12 @@ bool bpf_opcode_in_insntable(u8 code)
}
#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);
return -EFAULT;
}
+
/**
* __bpf_prog_run - run eBPF program on a given context
* @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers
@@ -1569,9 +1570,9 @@ static u64 __no_fgcse ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u6
LDST(W, u32)
LDST(DW, u64)
#undef LDST
-#define LDX_PROBE(SIZEOP, SIZE) \
- LDX_PROBE_MEM_##SIZEOP: \
- bpf_probe_read(&DST, SIZE, (const void *)(long) SRC); \
+#define LDX_PROBE(SIZEOP, SIZE) \
+ LDX_PROBE_MEM_##SIZEOP: \
+ bpf_probe_read_kernel(&DST, SIZE, (const void *)(long) SRC); \
CONT;
LDX_PROBE(B, 1)
LDX_PROBE(H, 2)
--
2.21.0
