conterm/libsec/decodepem.c
Russ Cox 934846f35c a
2005-08-08 12:50:13 +00:00

60 lines
1.3 KiB
C

#include <u.h>
#include <libc.h>
#include <mp.h>
#include <libsec.h>
#define STRLEN(s) (sizeof(s)-1)
uchar*
decodepem(char *s, char *type, int *len)
{
uchar *d;
char *t, *e, *tt;
int n;
/*
* find the correct section of the file, stripping garbage at the beginning and end.
* the data is delimited by -----BEGIN <type>-----\n and -----END <type>-----\n
*/
n = strlen(type);
e = strchr(s, '\0');
for(t = s; t != nil && t < e; ){
tt = t;
t = strchr(tt, '\n');
if(t != nil)
t++;
if(strncmp(tt, "-----BEGIN ", STRLEN("-----BEGIN ")) == 0
&& strncmp(&tt[STRLEN("-----BEGIN ")], type, n) == 0
&& strncmp(&tt[STRLEN("-----BEGIN ")+n], "-----\n", STRLEN("-----\n")) == 0)
break;
}
for(tt = t; tt != nil && tt < e; tt++){
if(strncmp(tt, "-----END ", STRLEN("-----END ")) == 0
&& strncmp(&tt[STRLEN("-----END ")], type, n) == 0
&& strncmp(&tt[STRLEN("-----END ")+n], "-----\n", STRLEN("-----\n")) == 0)
break;
tt = strchr(tt, '\n');
if(tt == nil)
break;
}
if(tt == nil || tt == e){
werrstr("incorrect .pem file format: bad header or trailer");
return nil;
}
n = ((tt - t) * 6 + 7) / 8;
d = malloc(n);
if(d == nil){
werrstr("out of memory");
return nil;
}
n = dec64(d, n, t, tt - t);
if(n < 0){
free(d);
werrstr("incorrect .pem file format: bad base64 encoded data");
return nil;
}
*len = n;
return d;
}