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*
9 decodepem(char *s, char *type, int *len, char **news)
10 {
11 	uchar *d;
12 	char *t, *e, *tt;
13 	int n;
14 
15 	*len = 0;
16 
17 	/*
18 	 * find the correct section of the file, stripping garbage at the beginning and end.
19 	 * the data is delimited by -----BEGIN <type>-----\n and -----END <type>-----\n
20 	 */
21 	n = strlen(type);
22 	e = strchr(s, '\0');
23 	for(t = s; t != nil && t < e; ){
24 		tt = t;
25 		t = strchr(tt, '\n');
26 		if(t != nil)
27 			t++;
28 		if(strncmp(tt, "-----BEGIN ", STRLEN("-----BEGIN ")) == 0
29 		&& strncmp(&tt[STRLEN("-----BEGIN ")], type, n) == 0
30 		&& strncmp(&tt[STRLEN("-----BEGIN ")+n], "-----\n", STRLEN("-----\n")) == 0)
31 			break;
32 	}
33 	for(tt = t; tt != nil && tt < e; tt++){
34 		if(strncmp(tt, "-----END ", STRLEN("-----END ")) == 0
35 		&& strncmp(&tt[STRLEN("-----END ")], type, n) == 0
36 		&& strncmp(&tt[STRLEN("-----END ")+n], "-----\n", STRLEN("-----\n")) == 0)
37 			break;
38 		tt = strchr(tt, '\n');
39 		if(tt == nil)
40 			break;
41 	}
42 	if(tt == nil || tt == e){
43 		werrstr("incorrect .pem file format: bad header or trailer");
44 		return nil;
45 	}
46 
47 	if(news)
48 		*news = tt+1;
49 	n = ((tt - t) * 6 + 7) / 8;
50 	d = malloc(n);
51 	if(d == nil){
52 		werrstr("out of memory");
53 		return nil;
54 	}
55 	n = dec64(d, n, t, tt - t);
56 	if(n < 0){
57 		free(d);
58 		werrstr("incorrect .pem file format: bad base64 encoded data");
59 		return nil;
60 	}
61 	*len = n;
62 	return d;
63 }
64 
65 PEMChain*
66 decodepemchain(char *s, char *type)
67 {
68 	PEMChain *first = nil, *last = nil, *chp;
69 	uchar *d;
70 	char *e;
71 	int n;
72 
73 	e = strchr(s, '\0');
74 	while (s < e) {
75 		d = decodepem(s, type, &n, &s);
76 		if(d == nil)
77 			break;
78 		chp = malloc(sizeof(PEMChain));
79 		chp->next = nil;
80 		chp->pem = d;
81 		chp->pemlen = n;
82 		if (first == nil)
83 			first = chp;
84 		else
85 			last->next = chp;
86 		last = chp;
87 	}
88 	return first;
89 }