Subversion Repositories planix.SVN

#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;
}