Commit b40a5d72 authored by Sami Tolvanen's avatar Sami Tolvanen Committed by Alexei Starovoitov
Browse files

bpf: crypto: Use the correct destructor kfunc type 



With CONFIG_CFI enabled, the kernel strictly enforces that indirect
function calls use a function pointer type that matches the target
function. I ran into the following type mismatch when running BPF
self-tests:

  CFI failure at bpf_obj_free_fields+0x190/0x238 (target:
    bpf_crypto_ctx_release+0x0/0x94; expected type: 0xa488ebfc)
  Internal error: Oops - CFI: 00000000f2008228 [#1]  SMP
  ...

As bpf_crypto_ctx_release() is also used in BPF programs and using
a void pointer as the argument would make the verifier unhappy, add
a simple stub function with the correct type and register it as the
destructor kfunc instead.

Signed-off-by: default avatarSami Tolvanen <samitolvanen@google.com>
Acked-by: default avatarYonghong Song <yonghong.song@linux.dev>
Tested-by: default avatarViktor Malik <vmalik@redhat.com>
Link: https://lore.kernel.org/r/20260110082548.113748-7-samitolvanen@google.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 5714ca8c

kernel/bpf/crypto.c

+7 −1
Original line number Diff line number Diff line
@@ -261,6 +261,12 @@ __bpf_kfunc void bpf_crypto_ctx_release(struct bpf_crypto_ctx *ctx) 
		call_rcu(&ctx->rcu, crypto_free_cb);

}



__bpf_kfunc void bpf_crypto_ctx_release_dtor(void *ctx)

{

	bpf_crypto_ctx_release(ctx);

}

CFI_NOSEAL(bpf_crypto_ctx_release_dtor);



static int bpf_crypto_crypt(const struct bpf_crypto_ctx *ctx,

			    const struct bpf_dynptr_kern *src,

			    const struct bpf_dynptr_kern *dst,
@@ -368,7 +374,7 @@ static const struct btf_kfunc_id_set crypt_kfunc_set = { 


BTF_ID_LIST(bpf_crypto_dtor_ids)

BTF_ID(struct, bpf_crypto_ctx)

BTF_ID(func, bpf_crypto_ctx_release)

BTF_ID(func, bpf_crypto_ctx_release_dtor)



static int __init crypto_kfunc_init(void)

{