From: David Howells dhowells@redhat.com
hulk inclusion category: feature feature: digest-lists
---------------------------
Provide a simple parser that extracts the packets from a PGP packet blob and passes the desirous ones to the given processor function:
struct pgp_parse_context { u64 types_of_interest; int (*process_packet)(struct pgp_parse_context *context, enum pgp_packet_tag type, u8 headerlen, const u8 *data, size_t datalen); };
int pgp_parse_packets(const u8 *data, size_t datalen, struct pgp_parse_context *ctx);
This is configured on with CONFIG_PGP_LIBRARY.
Changelog
v0: - fix style issues (Roberto Sassu) - declare pgp_to_public_key_algo (Roberto Sassu)
Signed-off-by: David Howells dhowells@redhat.com Co-developed-by: Roberto Sassu roberto.sassu@huawei.com Signed-off-by: Roberto Sassu roberto.sassu@huawei.com --- crypto/asymmetric_keys/Kconfig | 6 + crypto/asymmetric_keys/Makefile | 5 + crypto/asymmetric_keys/pgp_library.c | 281 +++++++++++++++++++++++++++ crypto/asymmetric_keys/pgp_parser.h | 23 +++ include/linux/pgplib.h | 48 +++++ 5 files changed, 363 insertions(+) create mode 100644 crypto/asymmetric_keys/pgp_library.c create mode 100644 crypto/asymmetric_keys/pgp_parser.h create mode 100644 include/linux/pgplib.h
diff --git a/crypto/asymmetric_keys/Kconfig b/crypto/asymmetric_keys/Kconfig index d8a73d94bb30..37b3bb7d59f0 100644 --- a/crypto/asymmetric_keys/Kconfig +++ b/crypto/asymmetric_keys/Kconfig @@ -65,4 +65,10 @@ config SIGNED_PE_FILE_VERIFICATION This option provides support for verifying the signature(s) on a signed PE binary.
+config PGP_LIBRARY + tristate "PGP parsing library" + help + This option enables a library that provides a number of simple + utility functions for parsing PGP (RFC 4880) packet-based messages. + endif # ASYMMETRIC_KEY_TYPE diff --git a/crypto/asymmetric_keys/Makefile b/crypto/asymmetric_keys/Makefile index d4b2e1b2dc65..966b67409ec3 100644 --- a/crypto/asymmetric_keys/Makefile +++ b/crypto/asymmetric_keys/Makefile @@ -61,3 +61,8 @@ verify_signed_pefile-y := \
$(obj)/mscode_parser.o: $(obj)/mscode.asn1.h $(obj)/mscode.asn1.h $(obj)/mscode.asn1.o: $(obj)/mscode.asn1.c $(obj)/mscode.asn1.h + +# +# PGP handling +# +obj-$(CONFIG_PGP_LIBRARY) += pgp_library.o diff --git a/crypto/asymmetric_keys/pgp_library.c b/crypto/asymmetric_keys/pgp_library.c new file mode 100644 index 000000000000..e2a1dda707f0 --- /dev/null +++ b/crypto/asymmetric_keys/pgp_library.c @@ -0,0 +1,281 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* PGP packet parser (RFC 4880) + * + * Copyright (C) 2011 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define pr_fmt(fmt) "PGPL: "fmt +#include <linux/pgplib.h> +#include <linux/errno.h> +#include <linux/kernel.h> +#include <linux/module.h> + +MODULE_LICENSE("GPL"); + +const char *const pgp_hash_algorithms[PGP_HASH__LAST] = { + [PGP_HASH_MD5] = "md5", + [PGP_HASH_SHA1] = "sha1", + [PGP_HASH_RIPE_MD_160] = "rmd160", + [PGP_HASH_SHA256] = "sha256", + [PGP_HASH_SHA384] = "sha384", + [PGP_HASH_SHA512] = "sha512", + [PGP_HASH_SHA224] = "sha224", +}; +EXPORT_SYMBOL_GPL(pgp_hash_algorithms); + +const char *pgp_to_public_key_algo[PGP_PUBKEY__LAST] = { + [PGP_PUBKEY_RSA_ENC_OR_SIG] = "rsa", + [PGP_PUBKEY_RSA_ENC_ONLY] = "rsa", + [PGP_PUBKEY_RSA_SIG_ONLY] = "rsa", + [PGP_PUBKEY_ELGAMAL] = NULL, + [PGP_PUBKEY_DSA] = NULL, +}; +EXPORT_SYMBOL_GPL(pgp_to_public_key_algo); + +/** + * pgp_parse_packet_header - Parse a PGP packet header + * @_data: Start of the PGP packet (updated to PGP packet data) + * @_datalen: Amount of data remaining in buffer (decreased) + * @_type: Where the packet type will be returned + * @_headerlen: Where the header length will be returned + * + * Parse a set of PGP packet header [RFC 4880: 4.2]. + * + * Returns packet data size on success; non-zero on error. If successful, + * *_data and *_datalen will have been updated and *_headerlen will be set to + * hold the length of the packet header. + */ +static ssize_t pgp_parse_packet_header(const u8 **_data, size_t *_datalen, + enum pgp_packet_tag *_type, + u8 *_headerlen) +{ + enum pgp_packet_tag type; + const u8 *data = *_data; + size_t size, datalen = *_datalen; + + pr_devel("-->%s(,%zu,,)\n", __func__, datalen); + + if (datalen < 2) + goto short_packet; + + pr_devel("pkthdr %02x, %02x\n", data[0], data[1]); + + type = *data++; + datalen--; + if (!(type & 0x80)) { + pr_debug("Packet type does not have MSB set\n"); + return -EBADMSG; + } + type &= ~0x80; + + if (type & 0x40) { + /* New packet length format */ + type &= ~0x40; + pr_devel("new format: t=%u\n", type); + switch (data[0]) { + case 0x00 ... 0xbf: + /* One-byte length */ + size = data[0]; + data++; + datalen--; + *_headerlen = 2; + break; + case 0xc0 ... 0xdf: + /* Two-byte length */ + if (datalen < 2) + goto short_packet; + size = (data[0] - 192) * 256; + size += data[1] + 192; + data += 2; + datalen -= 2; + *_headerlen = 3; + break; + case 0xff: + /* Five-byte length */ + if (datalen < 5) + goto short_packet; + size = data[1] << 24; + size |= data[2] << 16; + size |= data[3] << 8; + size |= data[4]; + data += 5; + datalen -= 5; + *_headerlen = 6; + break; + default: + pr_debug("Partial body length packet not supported\n"); + return -EBADMSG; + } + } else { + /* Old packet length format */ + u8 length_type = type & 0x03; + + type >>= 2; + pr_devel("old format: t=%u lt=%u\n", type, length_type); + + switch (length_type) { + case 0: + /* One-byte length */ + size = data[0]; + data++; + datalen--; + *_headerlen = 2; + break; + case 1: + /* Two-byte length */ + if (datalen < 2) + goto short_packet; + size = data[0] << 8; + size |= data[1]; + data += 2; + datalen -= 2; + *_headerlen = 3; + break; + case 2: + /* Four-byte length */ + if (datalen < 4) + goto short_packet; + size = data[0] << 24; + size |= data[1] << 16; + size |= data[2] << 8; + size |= data[3]; + data += 4; + datalen -= 4; + *_headerlen = 5; + break; + default: + pr_debug("Indefinite length packet not supported\n"); + return -EBADMSG; + } + } + + pr_devel("datalen=%zu size=%zu", datalen, size); + if (datalen < size) + goto short_packet; + if ((int)size < 0) + goto too_big; + + *_data = data; + *_datalen = datalen; + *_type = type; + pr_devel("Found packet type=%u size=%zd\n", type, size); + return size; + +short_packet: + pr_debug("Attempt to parse short packet\n"); + return -EBADMSG; +too_big: + pr_debug("Signature subpacket size >2G\n"); + return -EMSGSIZE; +} + +/** + * pgp_parse_packets - Parse a set of PGP packets + * @_data: Data to be parsed (updated) + * @_datalen: Amount of data (updated) + * @ctx: Parsing context + * + * Parse a set of PGP packets [RFC 4880: 4]. + */ +int pgp_parse_packets(const u8 *data, size_t datalen, + struct pgp_parse_context *ctx) +{ + enum pgp_packet_tag type; + ssize_t pktlen; + u8 headerlen; + int ret; + + while (datalen > 2) { + pktlen = pgp_parse_packet_header(&data, &datalen, &type, + &headerlen); + if (pktlen < 0) + return pktlen; + + if ((ctx->types_of_interest >> type) & 1) { + ret = ctx->process_packet(ctx, type, headerlen, + data, pktlen); + if (ret < 0) + return ret; + } + data += pktlen; + datalen -= pktlen; + } + + if (datalen != 0) { + pr_debug("Excess octets in packet stream\n"); + return -EBADMSG; + } + + return 0; +} +EXPORT_SYMBOL_GPL(pgp_parse_packets); + +/** + * pgp_parse_public_key - Parse the common part of a PGP pubkey packet + * @_data: Content of packet (updated) + * @_datalen: Length of packet remaining (updated) + * @pk: Public key data + * + * Parse the common data struct for a PGP pubkey packet [RFC 4880: 5.5.2]. + */ +int pgp_parse_public_key(const u8 **_data, size_t *_datalen, + struct pgp_parse_pubkey *pk) +{ + const u8 *data = *_data; + size_t datalen = *_datalen; + unsigned int tmp; + + if (datalen < 12) { + pr_debug("Public key packet too short\n"); + return -EBADMSG; + } + + pk->version = *data++; + switch (pk->version) { + case PGP_KEY_VERSION_2: + case PGP_KEY_VERSION_3: + case PGP_KEY_VERSION_4: + break; + default: + pr_debug("Public key packet with unhandled version %d\n", + pk->version); + return -EBADMSG; + } + + tmp = *data++ << 24; + tmp |= *data++ << 16; + tmp |= *data++ << 8; + tmp |= *data++; + pk->creation_time = tmp; + if (pk->version == PGP_KEY_VERSION_4) { + pk->expires_at = 0; /* Have to get it from the selfsignature */ + } else { + unsigned short ndays; + + ndays = *data++ << 8; + ndays |= *data++; + if (ndays) + pk->expires_at = pk->creation_time + ndays * 86400UL; + else + pk->expires_at = 0; + datalen -= 2; + } + + pk->pubkey_algo = *data++; + datalen -= 6; + + pr_devel("%x,%x,%lx,%lx\n", + pk->version, pk->pubkey_algo, pk->creation_time, + pk->expires_at); + + *_data = data; + *_datalen = datalen; + return 0; +} +EXPORT_SYMBOL_GPL(pgp_parse_public_key); diff --git a/crypto/asymmetric_keys/pgp_parser.h b/crypto/asymmetric_keys/pgp_parser.h new file mode 100644 index 000000000000..56f9a2b48679 --- /dev/null +++ b/crypto/asymmetric_keys/pgp_parser.h @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* PGP crypto data parser internal definitions + * + * Copyright (C) 2011 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include <linux/pgp.h> + +#define kenter(FMT, ...) \ + pr_devel("==> %s("FMT")\n", __func__, ##__VA_ARGS__) +#define kleave(FMT, ...) \ + pr_devel("<== %s()"FMT"\n", __func__, ##__VA_ARGS__) + +/* + * pgp_library.c + */ +extern const char *pgp_to_public_key_algo[PGP_PUBKEY__LAST]; diff --git a/include/linux/pgplib.h b/include/linux/pgplib.h new file mode 100644 index 000000000000..51fcda15236c --- /dev/null +++ b/include/linux/pgplib.h @@ -0,0 +1,48 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* PGP library definitions (RFC 4880) + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#ifndef _LINUX_PGPLIB_H +#define _LINUX_PGPLIB_H + +#if IS_ENABLED(CONFIG_PGP_LIBRARY) || IS_ENABLED(CONFIG_PGP_LIBRARY_MODULE) + +#include <linux/pgp.h> + +/* + * PGP library packet parser + */ +struct pgp_parse_context { + u64 types_of_interest; + int (*process_packet)(struct pgp_parse_context *context, + enum pgp_packet_tag type, + u8 headerlen, + const u8 *data, + size_t datalen); +}; + +extern int pgp_parse_packets(const u8 *data, size_t datalen, + struct pgp_parse_context *ctx); + +struct pgp_parse_pubkey { + enum pgp_key_version version : 8; + enum pgp_pubkey_algo pubkey_algo : 8; + time_t creation_time; + time_t expires_at; +}; + +extern int pgp_parse_public_key(const u8 **_data, size_t *_datalen, + struct pgp_parse_pubkey *pk); + + +#endif /* CONFIG_PGP_LIBRARY */ + +#endif /* _LINUX_PGPLIB_H */