jehanne/sys/src/lib/sec/port/decodepem.c

88 lines
1.8 KiB
C

#include "os.h"
#include <libsec.h>
#define STRLEN(s) (sizeof(s)-1)
uint8_t*
decodePEM(char *s, char *type, int *len, char **new_s)
{
uint8_t *d;
char *t, *e, *tt;
int n;
*len = 0;
/*
* 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;
}
if(new_s)
*new_s = tt+1;
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;
}
PEMChain*
decodepemchain(char *s, char *type)
{
PEMChain *first = nil, *last = nil, *chp;
uint8_t *d;
char *e;
int n;
e = strchr(s, '\0');
while (s < e) {
d = decodePEM(s, type, &n, &s);
if(d == nil)
break;
chp = malloc(sizeof(PEMChain));
chp->next = nil;
chp->pem = d;
chp->pemlen = n;
if (first == nil)
first = chp;
else
last->next = chp;
last = chp;
}
return first;
}