1 #include <u.h>
2 #include <libc.h>
3 #include <mp.h>
4 #include <libsec.h>
5
6 #define STRLEN(s) (sizeof(s)-1)
7
8 uchar*
decodepem(char * s,char * type,int * len)9 decodepem(char *s, char *type, int *len)
10 {
11 uchar *d;
12 char *t, *e, *tt;
13 int n;
14
15 /*
16 * find the correct section of the file, stripping garbage at the beginning and end.
17 * the data is delimited by -----BEGIN <type>-----\n and -----END <type>-----\n
18 */
19 n = strlen(type);
20 e = strchr(s, '\0');
21 for(t = s; t != nil && t < e; ){
22 tt = t;
23 t = strchr(tt, '\n');
24 if(t != nil)
25 t++;
26 if(strncmp(tt, "-----BEGIN ", STRLEN("-----BEGIN ")) == 0
27 && strncmp(&tt[STRLEN("-----BEGIN ")], type, n) == 0
28 && strncmp(&tt[STRLEN("-----BEGIN ")+n], "-----\n", STRLEN("-----\n")) == 0)
29 break;
30 }
31 for(tt = t; tt != nil && tt < e; tt++){
32 if(strncmp(tt, "-----END ", STRLEN("-----END ")) == 0
33 && strncmp(&tt[STRLEN("-----END ")], type, n) == 0
34 && strncmp(&tt[STRLEN("-----END ")+n], "-----\n", STRLEN("-----\n")) == 0)
35 break;
36 tt = strchr(tt, '\n');
37 if(tt == nil)
38 break;
39 }
40 if(tt == nil || tt == e){
41 werrstr("incorrect .pem file format: bad header or trailer");
42 return nil;
43 }
44
45 n = ((tt - t) * 6 + 7) / 8;
46 d = malloc(n);
47 if(d == nil){
48 werrstr("out of memory");
49 return nil;
50 }
51 n = dec64(d, n, t, tt - t);
52 if(n < 0){
53 free(d);
54 werrstr("incorrect .pem file format: bad base64 encoded data");
55 return nil;
56 }
57 *len = n;
58 return d;
59 }
60