cregit-Linux how code gets into the kernel

Release 4.14 lib/oid_registry.c

Directory: lib
/* 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 <linux/module.h>
#include <linux/export.h>
#include <linux/oid_registry.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/bug.h>
#include "oid_registry_data.c"

MODULE_DESCRIPTION("OID Registry");
MODULE_AUTHOR("Red Hat, Inc.");
MODULE_LICENSE("GPL");

/**
 * 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; }

Contributors

PersonTokensPropCommitsCommitProp
David Howells286100.00%1100.00%
Total286100.00%1100.00%

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; if (bufsize <= count) return -ENOBUFS; bufsize -= count; } return ret; }

Contributors

PersonTokensPropCommitsCommitProp
David Howells21297.25%150.00%
Takashi Iwai62.75%150.00%
Total218100.00%2100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
David Howells65100.00%1100.00%
Total65100.00%1100.00%

EXPORT_SYMBOL_GPL(sprint_OID);

Overall Contributors

PersonTokensPropCommitsCommitProp
David Howells61899.04%375.00%
Takashi Iwai60.96%125.00%
Total624100.00%4100.00%
Directory: lib
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