acme-client: relax certificate parsing

[Florian Obser]

Relax parsing of pem files a bit. Apparently there are CAs that use
\r\n line endings.
>From Bartosz Kuzma as part of a larger diff.

OK?

diff --git certproc.c certproc.c
index 7fde96e970e..975e12afaaa 100644
--- certproc.c
+++ certproc.c
@@ -28,7 +28,8 @@
 
 #include "extern.h"
 
-#define MARKER "-----END CERTIFICATE-----\n"
+#define BEGIN_MARKER "-----BEGIN CERTIFICATE-----"
+#define END_MARKER "-----END CERTIFICATE-----"
 
 int
 certproc(int netsock, int filesock)
@@ -81,19 +82,25 @@ certproc(int netsock, int filesock)
        if ((csr = readbuf(netsock, COMM_CSR, &csrsz)) == NULL)
                goto out;
 
-       if (csrsz < strlen(MARKER)) {
+       if (csrsz < strlen(END_MARKER)) {
                warnx("invalid cert");
                goto out;
        }
 
-       chaincp = strstr(csr, MARKER);
+       chaincp = strstr(csr, END_MARKER);
 
        if (chaincp == NULL) {
                warnx("invalid cert");
                goto out;
        }
 
-       chaincp += strlen(MARKER);
+       chaincp += strlen(END_MARKER);
+
+       if ((chaincp = strstr(chaincp, BEGIN_MARKER)) == NULL) {
+               warnx("invalid certificate chain");
+               goto out;
+       }
+
        if ((chain = strdup(chaincp)) == NULL) {
                warn("strdup");
                goto out;


-- 
I'm not entirely sure you are real.