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Thu, 05 Sep 2024 16:06:45 +0100 (CET) From: Roberto Sassu To: zohar@linux.ibm.com, dmitry.kasatkin@gmail.com, eric.snowberg@oracle.com, corbet@lwn.net, akpm@linux-foundation.org, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, shuah@kernel.org, mcoquelin.stm32@gmail.com, alexandre.torgue@foss.st.com Cc: linux-integrity@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kselftest@vger.kernel.org, wufan@linux.microsoft.com, pbrobinson@gmail.com, zbyszek@in.waw.pl, hch@lst.de, mjg59@srcf.ucam.org, pmatilai@redhat.com, jannh@google.com, dhowells@redhat.com, jikos@kernel.org, mkoutny@suse.com, ppavlu@suse.com, petr.vorel@gmail.com, mzerqung@0pointer.de, kgold@linux.ibm.com, Roberto Sassu Subject: [PATCH v5 01/14] lib: Add TLV parser Date: Thu, 5 Sep 2024 17:05:30 +0200 Message-Id: <20240905150543.3766895-2-roberto.sassu@huaweicloud.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240905150543.3766895-1-roberto.sassu@huaweicloud.com> References: <20240905150543.3766895-1-roberto.sassu@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: LxC2BwDXZy_myNlmE0tUAA--.16274S3 X-Coremail-Antispam: 1UD129KBjvAXoW3CF15WF4fur1kWrWkWr4fuFg_yoW8Gw47Co Za9FWUur45Xr17u3W8ZF48Zr1UXry0gr43Aw13GrW3Wa40kF45Kr45tw43G3y3Jws8KFWU t3sxX343Jw4UKr1kn29KB7ZKAUJUUUU5529EdanIXcx71UUUUU7v73VFW2AGmfu7bjvjm3 AaLaJ3UjIYCTnIWjp_UUUO57kC6x804xWl14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK 8VAvwI8IcIk0rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_Jr 4l82xGYIkIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Gr0_Xr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26r4j6F4UM28EF7xvwVC2z280aVCY1x0267AK xVW8Jr0_Cr1UM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7 xfMcIj6xIIjxv20xvE14v26r1Y6r17McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Y z7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1lc7CjxVAaw2 AFwI0_Wrv_ZF1l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAq x4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6r W5MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Gr0_Xr1lIxAIcVC0I7IYx2IY6xkF 7I0E14v26r4UJVWxJr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14 v26r4j6F4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr1j6F4UJbIYCTnIWIevJa73UjIFyTuY vjxUVDDGUUUUU X-CM-SenderInfo: purev21wro2thvvxqx5xdzvxpfor3voofrz/1tbiAQARBGbZE3MK1wABsX From: Roberto Sassu Add a parser of a generic Type-Length-Value (TLV) format: +-----------------+------------------+-----------------+ | data type (u64) | num fields (u64) | total len (u64) | # header +--------------+--+---------+--------+---------+-------+ | field1 (u64) | len1 (u64) | value1 (u8 len1) | +--------------+------------+------------------+ | ... | ... | ... | # data +--------------+------------+------------------+ | fieldN (u64) | lenN (u64) | valueN (u8 lenN) | +--------------+------------+------------------+ [same as above, repeated N times] Each adopter can define its own data types and fields. The TLV parser does not need to be aware of those, but lets the adopter obtain the data and decide how to continue. After parsing each TLV header, call the header callback function with the callback data provided by the adopter. The latter can return 0, to skip processing of the TLV data, 1 to process the TLV data, or a negative value to stop processing the TLV data. After processing a TLV data entry, call the data callback function also with the callback data provided by the adopter. The latter can decide how to interpret the TLV data entry depending on the field ID. Nesting TLVs is also possible, the data callback function can call tlv_parse() to parse the inner structure. Signed-off-by: Roberto Sassu --- MAINTAINERS | 8 ++ include/linux/tlv_parser.h | 48 +++++++ include/uapi/linux/tlv_parser.h | 62 +++++++++ lib/Kconfig | 3 + lib/Makefile | 2 + lib/tlv_parser.c | 221 ++++++++++++++++++++++++++++++++ lib/tlv_parser.h | 17 +++ 7 files changed, 361 insertions(+) create mode 100644 include/linux/tlv_parser.h create mode 100644 include/uapi/linux/tlv_parser.h create mode 100644 lib/tlv_parser.c create mode 100644 lib/tlv_parser.h diff --git a/MAINTAINERS b/MAINTAINERS index 8766f3e5e87e..ba8d5c137bef 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -23055,6 +23055,14 @@ W: http://sourceforge.net/projects/tlan/ F: Documentation/networking/device_drivers/ethernet/ti/tlan.rst F: drivers/net/ethernet/ti/tlan.* +TLV PARSER +M: Roberto Sassu +L: linux-kernel@vger.kernel.org +S: Maintained +F: include/linux/tlv_parser.h +F: include/uapi/linux/tlv_parser.h +F: lib/tlv_parser.* + TMIO/SDHI MMC DRIVER M: Wolfram Sang L: linux-mmc@vger.kernel.org diff --git a/include/linux/tlv_parser.h b/include/linux/tlv_parser.h new file mode 100644 index 000000000000..6d9a655d9ec9 --- /dev/null +++ b/include/linux/tlv_parser.h @@ -0,0 +1,48 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2023-2024 Huawei Technologies Duesseldorf GmbH + * + * Author: Roberto Sassu + * + * Header file of TLV parser. + */ + +#ifndef _LINUX_TLV_PARSER_H +#define _LINUX_TLV_PARSER_H + +#include + +/** + * typedef hdr_callback - Callback after parsing TLV header + * @callback_data: Opaque data to supply to the header callback function + * @data_type: TLV data type + * @num_entries: Number of TLV data entries + * @total_len: Total length of TLV data + * + * This callback is invoked after a TLV header is parsed. + * + * Return: 0 to skip processing, 1 to do processing, a negative value on error. + */ +typedef int (*hdr_callback)(void *callback_data, __u64 data_type, + __u64 num_entries, __u64 total_len); + +/** + * typedef data_callback - Callback after parsing TLV data entry + * @callback_data: Opaque data to supply to the data callback function + * @field: TLV field ID + * @field_data: Data of a TLV data field + * @field_len: Length of @field_data + * + * This callback is invoked after a TLV data entry is parsed. + * + * Return: 0 on success, a negative value on error. + */ +typedef int (*data_callback)(void *callback_data, __u64 field, + const __u8 *field_data, __u64 field_len); + +int tlv_parse(hdr_callback hdr_callback, void *hdr_callback_data, + data_callback data_callback, void *data_callback_data, + const __u8 *data, size_t data_len, const char **data_types, + __u64 num_data_types, const char **fields, __u64 num_fields); + +#endif /* _LINUX_TLV_PARSER_H */ diff --git a/include/uapi/linux/tlv_parser.h b/include/uapi/linux/tlv_parser.h new file mode 100644 index 000000000000..fbd4fc403ac7 --- /dev/null +++ b/include/uapi/linux/tlv_parser.h @@ -0,0 +1,62 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * Copyright (C) 2023-2024 Huawei Technologies Duesseldorf GmbH + * + * Author: Roberto Sassu + * + * Implement the user space interface for the TLV parser. + */ + +#ifndef _UAPI_LINUX_TLV_PARSER_H +#define _UAPI_LINUX_TLV_PARSER_H + +#include + +/* + * TLV format: + * + * +-----------------+------------------+-----------------+ + * | data type (u64) | num fields (u64) | total len (u64) | # header + * +--------------+--+---------+--------+---------+-------+ + * | field1 (u64) | len1 (u64) | value1 (u8 len1) | + * +--------------+------------+------------------+ + * | ... | ... | ... | # data + * +--------------+------------+------------------+ + * | fieldN (u64) | lenN (u64) | valueN (u8 lenN) | + * +--------------+------------+------------------+ + * + * [same as above, repeated N times] + * + */ + +/** + * struct tlv_hdr - Header of TLV format + * @data_type: Type of data to parse + * @num_entries: Number of data entries provided + * @_reserved: Reserved for future use (must be equal to zero) + * @total_len: Total length of the data blob, excluding the header + * + * This structure represents the header of the TLV data format. + */ +struct tlv_hdr { + __u64 data_type; + __u64 num_entries; + __u64 _reserved; + __u64 total_len; +} __attribute__((packed)); + +/** + * struct tlv_data_entry - Data entry of TLV format + * @field: Data field identifier + * @length: Data length + * @data: Data + * + * This structure represents a TLV data entry. + */ +struct tlv_data_entry { + __u64 field; + __u64 length; + __u8 data[]; +} __attribute__((packed)); + +#endif /* _UAPI_LINUX_TLV_PARSER_H */ diff --git a/lib/Kconfig b/lib/Kconfig index b38849af6f13..9141dcfc1704 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -777,3 +777,6 @@ config POLYNOMIAL config FIRMWARE_TABLE bool + +config TLV_PARSER + bool diff --git a/lib/Makefile b/lib/Makefile index 322bb127b4dc..c6c3614c4293 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -392,6 +392,8 @@ obj-$(CONFIG_USERCOPY_KUNIT_TEST) += usercopy_kunit.o obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) += devmem_is_allowed.o obj-$(CONFIG_FIRMWARE_TABLE) += fw_table.o +obj-$(CONFIG_TLV_PARSER) += tlv_parser.o +CFLAGS_tlv_parser.o += -I lib # FORTIFY_SOURCE compile-time behavior tests TEST_FORTIFY_SRCS = $(wildcard $(src)/test_fortify/*-*.c) diff --git a/lib/tlv_parser.c b/lib/tlv_parser.c new file mode 100644 index 000000000000..5d54844ab8d7 --- /dev/null +++ b/lib/tlv_parser.c @@ -0,0 +1,221 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2023-2024 Huawei Technologies Duesseldorf GmbH + * + * Author: Roberto Sassu + * + * Implement the TLV parser. + */ + +#define pr_fmt(fmt) "tlv_parser: "fmt +#include + +/** + * tlv_parse_hdr - Parse TLV header + * @hdr_callback: Callback function to call after parsing header + * @hdr_callback_data: Opaque data to supply to the header callback function + * @data: Data to parse (updated) + * @data_len: Length of @data (updated) + * @parsed_num_entries: Parsed number of data entries (updated) + * @parsed_total_len: Parsed length of TLV data, excluding the header (updated) + * @data_types: Array of data type strings + * @num_data_types: Number of elements of @data_types + * + * Parse the header of the TLV data format, move the data pointer to the TLV + * data part, decrease the data length by the length of the header, and provide + * the number of entries and the total data length extracted from the header. + * + * Before returning, call the header callback to let the callback supplier + * decide whether or not to process the subsequent TLV data. + * + * Return: 1 to process the data entries, 0 to skip, a negative value on error. + */ +static int tlv_parse_hdr(hdr_callback hdr_callback, void *hdr_callback_data, + const __u8 **data, size_t *data_len, + __u64 *parsed_num_entries, __u64 *parsed_total_len, + const char **data_types, __u64 num_data_types) +{ + __u64 parsed_data_type; + struct tlv_hdr *hdr; + + if (*data_len < sizeof(*hdr)) { + pr_debug("Data blob too short, %lu bytes, expected %lu\n", + *data_len, sizeof(*hdr)); + return -EBADMSG; + } + + hdr = (struct tlv_hdr *)*data; + + *data += sizeof(*hdr); + *data_len -= sizeof(*hdr); + + parsed_data_type = __be64_to_cpu(hdr->data_type); + if (parsed_data_type >= num_data_types) { + pr_debug("Invalid data type %llu, max: %llu\n", + parsed_data_type, num_data_types - 1); + return -EBADMSG; + } + + *parsed_num_entries = __be64_to_cpu(hdr->num_entries); + + if (hdr->_reserved != 0) { + pr_debug("_reserved must be zero\n"); + return -EBADMSG; + } + + *parsed_total_len = __be64_to_cpu(hdr->total_len); + if (*parsed_total_len > *data_len) { + pr_debug("Invalid total length %llu, expected: %lu\n", + *parsed_total_len, *data_len); + return -EBADMSG; + } + + pr_debug("Header: type: %s, num entries: %llu, total len: %lld\n", + data_types[parsed_data_type], *parsed_num_entries, + *parsed_total_len); + + return hdr_callback(hdr_callback_data, parsed_data_type, + *parsed_num_entries, *parsed_total_len); +} + +/** + * tlv_parse_data - Parse TLV data + * @data_callback: Callback function to call to parse the data entries + * @data_callback_data: Opaque data to supply to the data callback function + * @num_entries: Number of data entries to parse + * @data: Data to parse + * @data_len: Length of @data + * @fields: Array of field strings + * @num_fields: Number of elements of @fields + * + * Parse the data part of the TLV data format and call the supplied callback + * function for each data entry, passing also the opaque data pointer. + * + * The data callback function decides how to process data depending on the + * field. + * + * Return: 0 on success, a negative value on error. + */ +static int tlv_parse_data(data_callback data_callback, void *data_callback_data, + __u64 num_entries, const __u8 *data, size_t data_len, + const char **fields, __u64 num_fields) +{ + const __u8 *data_ptr = data; + struct tlv_data_entry *entry; + __u64 parsed_field, len, i, max_num_entries; + int ret; + + max_num_entries = data_len / sizeof(*entry); + + /* Possibly lower limit on num_entries loop. */ + if (num_entries > max_num_entries) + return -EBADMSG; + + for (i = 0; i < num_entries; i++) { + if (data_len < sizeof(*entry)) + return -EBADMSG; + + entry = (struct tlv_data_entry *)data_ptr; + data_ptr += sizeof(*entry); + data_len -= sizeof(*entry); + + parsed_field = __be64_to_cpu(entry->field); + if (parsed_field >= num_fields) { + pr_debug("Invalid field %llu, max: %llu\n", + parsed_field, num_fields - 1); + return -EBADMSG; + } + + len = __be64_to_cpu(entry->length); + + if (data_len < len) + return -EBADMSG; + + pr_debug("Data: field: %s, len: %llu\n", fields[parsed_field], + len); + + if (!len) + continue; + + ret = data_callback(data_callback_data, parsed_field, data_ptr, + len); + if (ret < 0) { + pr_debug("Parsing of field %s failed, ret: %d\n", + fields[parsed_field], ret); + return ret; + } + + data_ptr += len; + data_len -= len; + } + + if (data_len) { + pr_debug("Excess data: %lu bytes\n", data_len); + return -EBADMSG; + } + + return 0; +} + +/** + * tlv_parse - Parse data in TLV format + * @hdr_callback: Callback function to call after parsing header + * @hdr_callback_data: Opaque data to supply to the header callback function + * @data_callback: Callback function to call to parse the data entries + * @data_callback_data: Opaque data to supply to the data callback function + * @data: Data to parse + * @data_len: Length of @data + * @data_types: Array of data type strings + * @num_data_types: Number of elements of @data_types + * @fields: Array of field strings + * @num_fields: Number of elements of @fields + * + * Parse data in TLV format and call tlv_parse_data() each time tlv_parse_hdr() + * returns 1. + * + * Return: 0 on success, a negative value on error. + */ +int tlv_parse(hdr_callback hdr_callback, void *hdr_callback_data, + data_callback data_callback, void *data_callback_data, + const __u8 *data, size_t data_len, const char **data_types, + __u64 num_data_types, const char **fields, __u64 num_fields) +{ + __u64 parsed_num_entries, parsed_total_len; + const __u8 *data_ptr = data; + int ret = 0; + + pr_debug("Start parsing data blob, size: %lu\n", data_len); + + while (data_len) { + ret = tlv_parse_hdr(hdr_callback, hdr_callback_data, &data_ptr, + &data_len, &parsed_num_entries, + &parsed_total_len, data_types, + num_data_types); + switch (ret) { + case 0: + /* + * tlv_parse_hdr() already checked that + * parsed_total_len <= data_len. + */ + data_ptr += parsed_total_len; + data_len -= parsed_total_len; + continue; + case 1: + break; + default: + goto out; + } + + ret = tlv_parse_data(data_callback, data_callback_data, + parsed_num_entries, data_ptr, + parsed_total_len, fields, num_fields); + if (ret < 0) + goto out; + + data_ptr += parsed_total_len; + data_len -= parsed_total_len; + } +out: + pr_debug("End of parsing data blob, ret: %d\n", ret); + return ret; +} diff --git a/lib/tlv_parser.h b/lib/tlv_parser.h new file mode 100644 index 000000000000..8fa8127bd13e --- /dev/null +++ b/lib/tlv_parser.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2023-2024 Huawei Technologies Duesseldorf GmbH + * + * Author: Roberto Sassu + * + * Header file of TLV parser. + */ + +#ifndef _LIB_TLV_PARSER_H +#define _LIB_TLV_PARSER_H + +#include +#include +#include + +#endif /* _LIB_TLV_PARSER_H */