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 <dhowells@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
David Howells 2012-09-21 23:30:51 +01:00 committed by Rusty Russell
parent a77ad6ea0b
commit 4f73175d03
2 changed files with 83 additions and 0 deletions

View File

@ -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 */

View File

@ -11,6 +11,9 @@
#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"
/**
@ -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);