From a77ad6ea0b0bb1f9d1f52ed494bd72a5fdde208e Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 21 Sep 2012 23:30:46 +0100 Subject: X.509: Implement simple static OID registry Implement a simple static OID registry that allows the mapping of an encoded OID to an enum value for ease of use. The OID registry index enum appears in the: linux/oid_registry.h header file. A script generates the registry from lines in the header file that look like: OID_foo,/*1.2.3.4*/ The actual OID is taken to be represented by the numbers with interpolated dots in the comment. All other lines in the header are ignored. The registry is queries by calling: OID look_up_oid(const void *data, size_t datasize); This returns a number from the registry enum representing the OID if found or OID__NR if not. Signed-off-by: David Howells Signed-off-by: Rusty Russell --- lib/oid_registry.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 89 insertions(+) create mode 100644 lib/oid_registry.c (limited to 'lib/oid_registry.c') diff --git a/lib/oid_registry.c b/lib/oid_registry.c new file mode 100644 index 000000000000..33cfd171f627 --- /dev/null +++ b/lib/oid_registry.c @@ -0,0 +1,89 @@ +/* ASN.1 Object identifier (OID) registry + * + * 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. + */ + +#include +#include +#include "oid_registry_data.c" + +/** + * look_up_OID - Find an OID registration for the specified data + * @data: Binary representation of the OID + * @datasize: Size of the binary representation + */ +enum OID look_up_OID(const void *data, size_t datasize) +{ + const unsigned char *octets = data; + enum OID oid; + unsigned char xhash; + unsigned i, j, k, hash; + size_t len; + + /* Hash the OID data */ + hash = datasize - 1; + + for (i = 0; i < datasize; i++) + hash += octets[i] * 33; + hash = (hash >> 24) ^ (hash >> 16) ^ (hash >> 8) ^ hash; + hash &= 0xff; + + /* Binary search the OID registry. OIDs are stored in ascending order + * of hash value then ascending order of size and then in ascending + * order of reverse value. + */ + i = 0; + k = OID__NR; + while (i < k) { + j = (i + k) / 2; + + xhash = oid_search_table[j].hash; + if (xhash > hash) { + k = j; + continue; + } + if (xhash < hash) { + i = j + 1; + continue; + } + + oid = oid_search_table[j].oid; + len = oid_index[oid + 1] - oid_index[oid]; + if (len > datasize) { + k = j; + continue; + } + if (len < datasize) { + i = j + 1; + continue; + } + + /* Variation is most likely to be at the tail end of the + * OID, so do the comparison in reverse. + */ + while (len > 0) { + unsigned char a = oid_data[oid_index[oid] + --len]; + unsigned char b = octets[len]; + if (a > b) { + k = j; + goto next; + } + if (a < b) { + i = j + 1; + goto next; + } + } + return oid; + next: + ; + } + + return OID__NR; +} +EXPORT_SYMBOL_GPL(look_up_OID); -- cgit v1.2.3 From 4f73175d0375a7c1b3ae625e76acee8b39741f28 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 21 Sep 2012 23:30:51 +0100 Subject: X.509: Add utility functions to render OIDs as strings Add a pair of utility functions to render OIDs as strings. The first takes an encoded OID and turns it into a "a.b.c.d" form string: int sprint_oid(const void *data, size_t datasize, char *buffer, size_t bufsize); The second takes an OID enum index and calls the first on the data held therein: int sprint_OID(enum OID oid, char *buffer, size_t bufsize); Signed-off-by: David Howells Signed-off-by: Rusty Russell --- include/linux/oid_registry.h | 2 ++ lib/oid_registry.c | 81 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 83 insertions(+) (limited to 'lib/oid_registry.c') diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h index 5928546bf00a..6926db724258 100644 --- a/include/linux/oid_registry.h +++ b/include/linux/oid_registry.h @@ -86,5 +86,7 @@ enum OID { }; extern enum OID look_up_OID(const void *data, size_t datasize); +extern int sprint_oid(const void *, size_t, char *, size_t); +extern int sprint_OID(enum OID, char *, size_t); #endif /* _LINUX_OID_REGISTRY_H */ diff --git a/lib/oid_registry.c b/lib/oid_registry.c index 33cfd171f627..d8de11f45908 100644 --- a/lib/oid_registry.c +++ b/lib/oid_registry.c @@ -11,6 +11,9 @@ #include #include +#include +#include +#include #include "oid_registry_data.c" /** @@ -87,3 +90,81 @@ enum OID look_up_OID(const void *data, size_t datasize) return OID__NR; } EXPORT_SYMBOL_GPL(look_up_OID); + +/* + * sprint_OID - Print an Object Identifier into a buffer + * @data: The encoded OID to print + * @datasize: The size of the encoded OID + * @buffer: The buffer to render into + * @bufsize: The size of the buffer + * + * The OID is rendered into the buffer in "a.b.c.d" format and the number of + * bytes is returned. -EBADMSG is returned if the data could not be intepreted + * and -ENOBUFS if the buffer was too small. + */ +int sprint_oid(const void *data, size_t datasize, char *buffer, size_t bufsize) +{ + const unsigned char *v = data, *end = v + datasize; + unsigned long num; + unsigned char n; + size_t ret; + int count; + + if (v >= end) + return -EBADMSG; + + n = *v++; + ret = count = snprintf(buffer, bufsize, "%u.%u", n / 40, n % 40); + buffer += count; + bufsize -= count; + if (bufsize == 0) + return -ENOBUFS; + + while (v < end) { + num = 0; + n = *v++; + if (!(n & 0x80)) { + num = n; + } else { + num = n & 0x7f; + do { + if (v >= end) + return -EBADMSG; + n = *v++; + num <<= 7; + num |= n & 0x7f; + } while (n & 0x80); + } + ret += count = snprintf(buffer, bufsize, ".%lu", num); + buffer += count; + bufsize -= count; + if (bufsize == 0) + return -ENOBUFS; + } + + return ret; +} +EXPORT_SYMBOL_GPL(sprint_oid); + +/** + * sprint_OID - Print an Object Identifier into a buffer + * @oid: The OID to print + * @buffer: The buffer to render into + * @bufsize: The size of the buffer + * + * The OID is rendered into the buffer in "a.b.c.d" format and the number of + * bytes is returned. + */ +int sprint_OID(enum OID oid, char *buffer, size_t bufsize) +{ + int ret; + + BUG_ON(oid >= OID__NR); + + ret = sprint_oid(oid_data + oid_index[oid], + oid_index[oid + 1] - oid_index[oid], + buffer, bufsize); + BUG_ON(ret == -EBADMSG); + return ret; +} +EXPORT_SYMBOL_GPL(sprint_OID); -- cgit v1.2.3