From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-179.mta1.migadu.com (out-179.mta1.migadu.com [95.215.58.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 76C0529406 for ; Mon, 6 Nov 2023 16:39:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="b3+YCjG1" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1699288790; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=oN9A869VZHCBy48m5tePmOYoJKbQb+kLiJFQutRmqPQ=; b=b3+YCjG1D3/OMasxPQ3TVixojodUlNjX2S0fLv8KGgr72FzTRnd4/DDWhL5W428pId3nvv qsbijvUaho/aG5vSGdiy4wlE8Rzzumxyt4eMm9prMiHdh81IUSk9zPUtmvjiahR2CqCNfa V2/qepoxPkiL96qdazO6xow95ByHh54= Date: Mon, 6 Nov 2023 16:39:46 +0000 Precedence: bulk X-Mailing-List: fsverity@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH v12 bpf-next 1/9] bpf: Add __bpf_dynptr_data* for in kernel use Content-Language: en-US To: Song Liu , bpf@vger.kernel.org, fsverity@lists.linux.dev Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@kernel.org, kernel-team@meta.com, ebiggers@kernel.org, tytso@mit.edu, roberto.sassu@huaweicloud.com, kpsingh@kernel.org, vadfed@meta.com References: <20231104001313.3538201-1-song@kernel.org> <20231104001313.3538201-2-song@kernel.org> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Vadim Fedorenko In-Reply-To: <20231104001313.3538201-2-song@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 04/11/2023 00:13, Song Liu wrote: > Different types of bpf dynptr have different internal data storage. > Specifically, SKB and XDP type of dynptr may have non-continuous data. > Therefore, it is not always safe to directly access dynptr->data. > > Add __bpf_dynptr_data and __bpf_dynptr_data_rw to replace direct access to > dynptr->data. > > Update bpf_verify_pkcs7_signature to use __bpf_dynptr_data instead of > dynptr->data. > > Signed-off-by: Song Liu > --- > include/linux/bpf.h | 2 ++ > kernel/bpf/helpers.c | 47 ++++++++++++++++++++++++++++++++++++++++ > kernel/trace/bpf_trace.c | 12 ++++++---- > 3 files changed, 57 insertions(+), 4 deletions(-) > > diff --git a/include/linux/bpf.h b/include/linux/bpf.h > index b4825d3cdb29..eb84caf133df 100644 > --- a/include/linux/bpf.h > +++ b/include/linux/bpf.h > @@ -1222,6 +1222,8 @@ enum bpf_dynptr_type { > > int bpf_dynptr_check_size(u32 size); > u32 __bpf_dynptr_size(const struct bpf_dynptr_kern *ptr); > +const void *__bpf_dynptr_data(const struct bpf_dynptr_kern *ptr, u32 len); > +void *__bpf_dynptr_data_rw(const struct bpf_dynptr_kern *ptr, u32 len); > > #ifdef CONFIG_BPF_JIT > int bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr); > diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c > index e46ac288a108..c569c4c43bde 100644 > --- a/kernel/bpf/helpers.c > +++ b/kernel/bpf/helpers.c > @@ -2611,3 +2611,50 @@ static int __init kfunc_init(void) > } > > late_initcall(kfunc_init); > + > +/* Get a pointer to dynptr data up to len bytes for read only access. If > + * the dynptr doesn't have continuous data up to len bytes, return NULL. > + */ > +const void *__bpf_dynptr_data(const struct bpf_dynptr_kern *ptr, u32 len) > +{ > + enum bpf_dynptr_type type; > + int err; > + > + if (!ptr->data) > + return NULL; > + > + err = bpf_dynptr_check_off_len(ptr, 0, len); > + if (err) > + return NULL; > + type = bpf_dynptr_get_type(ptr); > + > + switch (type) { > + case BPF_DYNPTR_TYPE_LOCAL: > + case BPF_DYNPTR_TYPE_RINGBUF: > + return ptr->data + ptr->offset; > + case BPF_DYNPTR_TYPE_SKB: > + return skb_pointer_if_linear(ptr->data, ptr->offset, len); > + case BPF_DYNPTR_TYPE_XDP: > + { > + void *xdp_ptr = bpf_xdp_pointer(ptr->data, ptr->offset, len); > + > + if (IS_ERR_OR_NULL(xdp_ptr)) > + return NULL; > + return xdp_ptr; > + } > + default: > + WARN_ONCE(true, "unknown dynptr type %d\n", type); > + return NULL; > + } > +} > + > +/* Get a pointer to dynptr data up to len bytes for read write access. If > + * the dynptr doesn't have continuous data up to len bytes, or the dynptr > + * is read only, return NULL. > + */ > +void *__bpf_dynptr_data_rw(const struct bpf_dynptr_kern *ptr, u32 len) > +{ > + if (__bpf_dynptr_is_rdonly(ptr)) > + return NULL; > + return (void *)__bpf_dynptr_data(ptr, len); > +} > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > index df697c74d519..d525a22b8d56 100644 > --- a/kernel/trace/bpf_trace.c > +++ b/kernel/trace/bpf_trace.c > @@ -1378,6 +1378,8 @@ __bpf_kfunc int bpf_verify_pkcs7_signature(struct bpf_dynptr_kern *data_ptr, > struct bpf_dynptr_kern *sig_ptr, > struct bpf_key *trusted_keyring) > { > + const void *data, *sig; > + u32 data_len, sig_len; > int ret; > > if (trusted_keyring->has_ref) { > @@ -1394,10 +1396,12 @@ __bpf_kfunc int bpf_verify_pkcs7_signature(struct bpf_dynptr_kern *data_ptr, > return ret; > } > > - return verify_pkcs7_signature(data_ptr->data, > - __bpf_dynptr_size(data_ptr), > - sig_ptr->data, > - __bpf_dynptr_size(sig_ptr), > + data_len = __bpf_dynptr_size(data_ptr); > + data = __bpf_dynptr_data(data_ptr, data_len); > + sig_len = __bpf_dynptr_size(sig_ptr); > + sig = __bpf_dynptr_data(sig_ptr, sig_len); > + > + return verify_pkcs7_signature(data, data_len, sig, sig_len, > trusted_keyring->key, > VERIFYING_UNSPECIFIED_SIGNATURE, NULL, > NULL); Acked-by: Vadim Fedorenko