Is there any OpenSSL function to convert PKCS7 file to PEM

Question

Hi,

Is there any openssl api function to convert PKCS7 file to PEM. I am able to convert a PKCS12 file to PEM using PKCS12_parse() function which returns key and certificate given the password. There is no similar function for pkcs7.

My pkcs7 input has just the certificate in binary format. I am able to do the conversion using command

openssl pkcs7 -inform DER -in input.p7b -printcerts -text

How do I do this in a C program? I am able to read it to a PKCS7 structure like this

FILE* fp; if (!(fp = fopen("ca.p7b", "rb"))) { fprintf(stderr, "Error reading input pkcs7 file\n" ); exit(1); } PKCS7 *p7; p7 = d2i_PKCS7_fp(cafp, NULL);

Answer 1

After some googling I am able to do that.

if(p7->d.sign->cert != NULL){
    PEM_write_X509(fp, sk_X509_value(p7->d.sign->cert, 0)); 
}

where p7 is a pointer to pkcs7 struct and fp is the file pointer to PEM file