From patchwork Wed May 8 10:26:42 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Tissoires X-Patchwork-Id: 13658477 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 4D9D981205; Wed, 8 May 2024 10:27:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715164047; cv=none; b=dHEpGDOvhKDKVT4xYZqpgRiywgsliYblr7/i+aSd1zFeUcXpy1utrnqaj2ykJ8wtXaIkEtYT4pAhonMvBj6Wc1dSLxhQDyIrrnxKTVEXYUIla534nS7gBmI/5knM8bvzd/cjhSfOS8XhkhHIGzkGe+1SlIMlwF8UepR5Mo9fKlw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715164047; c=relaxed/simple; bh=gUKFJUJPIS9WSId/kAlnSuXYsqfcoTxB16GBAeCmvtM=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=iBKS7nZbMkrmCtTMRKHWUj5Sr1rhNOylokKVymU7G4886rF7RLBFcjAAT298uf+nf/wD9GgQycWQwso4wIekCKLUJWemmOZOtsZrH/CPQq0iKhDmt2J362JhSjqMuY2rOGXL6WR+X7waHyr00M0HZsFELFthgwh1WwGUVxKYag8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BW/Vy9Ib; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="BW/Vy9Ib" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E2C82C113CC; Wed, 8 May 2024 10:27:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1715164046; bh=gUKFJUJPIS9WSId/kAlnSuXYsqfcoTxB16GBAeCmvtM=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=BW/Vy9IbQHb6Xu1wRBvlOofA1YOU0lJykkWaritCmqUuu82LaZPvVSmzavHJHYAGv KJ5e5cVTv51gGM8WAgzeyss9pf7Y+bKSe/O4h1YJzKVmRdU33YNxSYvrYmaTXaC85M 31PQ0G7uuQp/3CelVX7u/yVbr9ouxiaY/X724DKJM+rO7XjdyJm9nPSedm22ewCyYc KIc3uWMU7INsxwsblwsfFTrRqiKsL02mRHapHByqGH3WACX1NGHTk5znv+yYj4YmcS qf0OEjbCznyTHLkdJQ3cKWEjxWRCEGFzvlBMAqY+9sASq9q/T2p3NJVBtwGHtacuU0 rB9y1qGx0hMKg== From: Benjamin Tissoires Date: Wed, 08 May 2024 12:26:42 +0200 Subject: [PATCH RFC HID 7/7] HID: bpf: prevent infinite recursions with hid_hw_raw_requests hooks Precedence: bulk X-Mailing-List: linux-input@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240508-hid_bpf_async_fun-v1-7-558375a25657@kernel.org> References: <20240508-hid_bpf_async_fun-v1-0-558375a25657@kernel.org> In-Reply-To: <20240508-hid_bpf_async_fun-v1-0-558375a25657@kernel.org> To: Benjamin Tissoires Cc: linux-kernel@vger.kernel.org, linux-input@vger.kernel.org, bpf@vger.kernel.org, Benjamin Tissoires X-Mailer: b4 0.12.4 X-Developer-Signature: v=1; a=ed25519-sha256; t=1715164017; l=6266; i=bentiss@kernel.org; s=20230215; h=from:subject:message-id; bh=gUKFJUJPIS9WSId/kAlnSuXYsqfcoTxB16GBAeCmvtM=; b=0bdx+qfpQLf9Bz1Uqnyq7kMhIlO/zMh96gqCYtYn9gWtjJlHx6wCndVGc6OyN4s5jmDj+RZtN HrqpptNkGzUCZCimmxCtyLvnNQ/y3DJ1PkfkFrenAxEd8/e00SPShD6 X-Developer-Key: i=bentiss@kernel.org; a=ed25519; pk=7D1DyAVh6ajCkuUTudt/chMuXWIJHlv2qCsRkIizvFw= When we attach a sleepable hook to hid_hw_raw_requests, we can (and in many cases should) call ourself hid_bpf_raw_request(), to actaully fetch data from the device itself. However, this means that we might enter an infinite loop between hid_hw_raw_requests trace and hid_bpf_raw_request() call. To prevent that, if a hid_bpf_raw_request() call is emitted, we prevent any sleepable bpf trace to hid_hw_raw_requests(). This way we can always trace/monitor/filter the incoming bpf requests, while preventing those loops to happen. Signed-off-by: Benjamin Tissoires --- drivers/hid/bpf/hid_bpf_dispatch.c | 7 ++++--- drivers/hid/hid-core.c | 6 +++--- drivers/hid/hidraw.c | 4 ++-- include/linux/hid.h | 2 +- include/linux/hid_bpf.h | 6 +++--- 5 files changed, 13 insertions(+), 12 deletions(-) diff --git a/drivers/hid/bpf/hid_bpf_dispatch.c b/drivers/hid/bpf/hid_bpf_dispatch.c index 7aeab3f9f2c7..79cac293ba29 100644 --- a/drivers/hid/bpf/hid_bpf_dispatch.c +++ b/drivers/hid/bpf/hid_bpf_dispatch.c @@ -99,7 +99,7 @@ dispatch_hid_bpf_raw_requests(struct hid_device *hdev, unsigned char reportnum, u8 *buf, u32 *size, enum hid_report_type rtype, enum hid_class_request reqtype, - u64 source) + u64 source, bool from_bpf) { struct hid_bpf_ctx_kern ctx_kern = { .ctx = { @@ -122,7 +122,7 @@ dispatch_hid_bpf_raw_requests(struct hid_device *hdev, // if (!hdev->bpf.device_data) // return buf; - ret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_RAW_REQUEST, &ctx_kern, true); + ret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_RAW_REQUEST, &ctx_kern, !from_bpf); if (ret < 0) return ERR_PTR(ret); @@ -536,7 +536,8 @@ hid_bpf_hw_request(struct hid_bpf_ctx *ctx, __u8 *buf, size_t buf__sz, size, rtype, reqtype, - (__u64)ctx); + (__u64)ctx, + true); /* prevent infinite recursions */ if (ret > 0) memcpy(buf, dma_data, ret); diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index 7d468f6dbefe..d53f465a4ccb 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -2404,7 +2404,7 @@ int __hid_hw_raw_request(struct hid_device *hdev, unsigned char reportnum, __u8 *buf, size_t len, enum hid_report_type rtype, enum hid_class_request reqtype, - __u64 source) + __u64 source, bool from_bpf) { unsigned int max_buffer_size = HID_MAX_BUFFER_SIZE; u32 size = (u32)len; /* max_buffer_size is 16 KB */ @@ -2416,7 +2416,7 @@ int __hid_hw_raw_request(struct hid_device *hdev, return -EINVAL; buf = dispatch_hid_bpf_raw_requests(hdev, reportnum, buf, &size, rtype, - reqtype, source); + reqtype, source, from_bpf); if (IS_ERR(buf)) return PTR_ERR(buf); @@ -2442,7 +2442,7 @@ int hid_hw_raw_request(struct hid_device *hdev, unsigned char reportnum, __u8 *buf, size_t len, enum hid_report_type rtype, enum hid_class_request reqtype) { - return __hid_hw_raw_request(hdev, reportnum, buf, len, rtype, reqtype, 0); + return __hid_hw_raw_request(hdev, reportnum, buf, len, rtype, reqtype, 0, false); } EXPORT_SYMBOL_GPL(hid_hw_raw_request); diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c index 6d2a6d38e42a..4ba3131de614 100644 --- a/drivers/hid/hidraw.c +++ b/drivers/hid/hidraw.c @@ -151,7 +151,7 @@ static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, } ret = __hid_hw_raw_request(dev, buf[0], buf, count, report_type, - HID_REQ_SET_REPORT, (__u64)file); + HID_REQ_SET_REPORT, (__u64)file, false); out_free: kfree(buf); @@ -228,7 +228,7 @@ static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t } ret = __hid_hw_raw_request(dev, report_number, buf, count, report_type, - HID_REQ_GET_REPORT, (__u64)file); + HID_REQ_GET_REPORT, (__u64)file, false); if (ret < 0) goto out_free; diff --git a/include/linux/hid.h b/include/linux/hid.h index dac2804b4562..24d0d7c0bd33 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -1129,7 +1129,7 @@ int __hid_hw_raw_request(struct hid_device *hdev, unsigned char reportnum, __u8 *buf, size_t len, enum hid_report_type rtype, enum hid_class_request reqtype, - __u64 source); + __u64 source, bool from_bpf); int __hid_hw_output_report(struct hid_device *hdev, __u8 *buf, size_t len, __u64 source); int hid_hw_raw_request(struct hid_device *hdev, unsigned char reportnum, __u8 *buf, diff --git a/include/linux/hid_bpf.h b/include/linux/hid_bpf.h index 1cd36bfdd608..6b2ac815572c 100644 --- a/include/linux/hid_bpf.h +++ b/include/linux/hid_bpf.h @@ -105,7 +105,7 @@ struct hid_bpf_ops { unsigned char reportnum, __u8 *buf, size_t len, enum hid_report_type rtype, enum hid_class_request reqtype, - __u64 source); + __u64 source, bool from_bpf); int (*hid_hw_output_report)(struct hid_device *hdev, __u8 *buf, size_t len, __u64 source); int (*hid_input_report)(struct hid_device *hid, enum hid_report_type type, @@ -148,7 +148,7 @@ u8 *dispatch_hid_bpf_raw_requests(struct hid_device *hdev, unsigned char reportnum, __u8 *buf, u32 *size, enum hid_report_type rtype, enum hid_class_request reqtype, - __u64 source); + __u64 source, bool from_bpf); int hid_bpf_connect_device(struct hid_device *hdev); void hid_bpf_disconnect_device(struct hid_device *hdev); void hid_bpf_destroy_device(struct hid_device *hid); @@ -162,7 +162,7 @@ static inline u8 *dispatch_hid_bpf_raw_requests(struct hid_device *hdev, unsigned char reportnum, u8 *buf, u32 *size, enum hid_report_type rtype, enum hid_class_request reqtype, - u64 source) { return buf; } + u64 source, bool from_bpf) { return buf; } static inline int hid_bpf_connect_device(struct hid_device *hdev) { return 0; } static inline void hid_bpf_disconnect_device(struct hid_device *hdev) {} static inline void hid_bpf_destroy_device(struct hid_device *hid) {}