From patchwork Fri Nov 3 23:01:56 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 13445229 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 07B8A2374F; Fri, 3 Nov 2023 23:02:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Bdq6Kitk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CE17CC433C7; Fri, 3 Nov 2023 23:02:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1699052555; bh=7pkyYFUeToGDQQO+jroBDuZMyqSZYqXCRpTGY9yXu3k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Bdq6KitkMolPiPoqmE7G56iI77P0fyRqP4SlSDx3jOa/dEFOKbjodex4nwQ85DGxO hpvcPC5ETPE2v8o1wx/bB9dA76zAAm5kEN2c3A04J2UbgsDn7PC1GpKSXtFEJKYjQI 6jUoao9WrdYU57+Y0P1TpudurLhn3z34jqE8soCsIJn/VfHK9iOVKe7gXPsEXG/46u 7HQ5u/VDDL/WU9mRZ0jJOZ5Z0siuRdznEGMpBVUbCG4gWQ5QrzG9XnqCe4q8Fo6V1E ZfpxtyNlNdJC4fHqrMJwqQ3IFENF0XNwRDFNReudjJrQch3DeED3IsXjNbGZxr0wns 8Y7QoEjloJ2wg== From: Song Liu To: 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, Song Liu Subject: [PATCH v11 bpf-next 1/9] bpf: Add __bpf_dynptr_data* for in kernel use Date: Fri, 3 Nov 2023 16:01:56 -0700 Message-Id: <20231103230204.3137000-2-song@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231103230204.3137000-1-song@kernel.org> References: <20231103230204.3137000-1-song@kernel.org> Precedence: bulk X-Mailing-List: fsverity@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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..0c6445427dca 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(data_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);