Commit e3775a33 authored by Dr. Stephen Henson's avatar Dr. Stephen Henson
Browse files

Make the PKCS#7 S/MIME functions check for passed NULL pointers. 

Fix the usage message of smime utility and sanitise the return
codes.

Add some documentation.
parent a4af39ac

apps/smime.c

+21 −7
Original line number Diff line number Diff line
@@ -136,6 +136,8 @@ int MAIN(int argc, char **argv) 
				flags &= ~PKCS7_DETACHED;

		else if (!strcmp (*args, "-binary"))

				flags |= PKCS7_BINARY;

		else if (!strcmp (*args, "-nosigs"))

				flags |= PKCS7_NOSIGS;

		else if (!strcmp (*args, "-to")) {

			if (args[1]) {

				args++;
@@ -224,6 +226,13 @@ int MAIN(int argc, char **argv) 
		BIO_printf (bio_err, "-rc2-40        encrypt with RC2-40\n");

		BIO_printf (bio_err, "-rc2-64        encrypt with RC2-64\n");

		BIO_printf (bio_err, "-rc2-128       encrypt with RC2-128\n");

		BIO_printf (bio_err, "-nointern      don't search certificates in message for signer\n");

		BIO_printf (bio_err, "-nosigs        don't verify message signature\n");

		BIO_printf (bio_err, "-noverify      don't verify signers certificate\n");

		BIO_printf (bio_err, "-nocerts       don't include signers certificate when signing\n");

		BIO_printf (bio_err, "-nodetach      use opaque signing\n");

		BIO_printf (bio_err, "-noattr        don't include any signed attributes\n");

		BIO_printf (bio_err, "-binary        don't translate message to text\n");

		BIO_printf (bio_err, "-in file       input file\n");

		BIO_printf (bio_err, "-certfile file other certificates file\n");

		BIO_printf (bio_err, "-signer file   signer certificate file\n");
@@ -235,6 +244,8 @@ int MAIN(int argc, char **argv) 
		BIO_printf (bio_err, "-from ad       from address\n");

		BIO_printf (bio_err, "-subject s     subject\n");

		BIO_printf (bio_err, "-text          include or delete text MIME headers\n");

		BIO_printf (bio_err, "-CApath dir    trusted certificates directory\n");

		BIO_printf (bio_err, "-CAfile file   trusted certificates file\n");

		BIO_printf (bio_err, "cert.pem       recipient certificate(s)\n");

		goto end;

	}
@@ -319,6 +330,7 @@ int MAIN(int argc, char **argv) 
		if(!(store = setup_verify(CAfile, CApath))) goto end;



	ret = 3;



	if(operation == SMIME_ENCRYPT) {

		p7 = PKCS7_encrypt(encerts, in, cipher, flags);

	} else if(operation == SMIME_SIGN) {
@@ -327,7 +339,6 @@ int MAIN(int argc, char **argv) 
	} else {

		if(!(p7 = SMIME_read_PKCS7(in, &indata))) {

			BIO_printf(bio_err, "Error reading S/MIME message\n");

			ret = 4;

			goto end;

		}

	}
@@ -337,24 +348,26 @@ int MAIN(int argc, char **argv) 
		goto end;

	}



	ret = 4;

	if(operation == SMIME_DECRYPT) {

		if(!PKCS7_decrypt(p7, key, recip, out, flags))

		if(!PKCS7_decrypt(p7, key, recip, out, flags)) {

			BIO_printf(bio_err, "Error decrypting PKCS#7 structure\n");

		else ret = 0;

			goto end;

		}

	} else if(operation == SMIME_VERIFY) {

		STACK_OF(X509) *signers;

		signers = PKCS7_iget_signers(p7, other, flags);

		if(PKCS7_verify(p7, other, store, indata, out, flags)) {

			BIO_printf(bio_err, "Verification Successful\n");

			ret = 0;

		} else {

			BIO_printf(bio_err, "Verification Failure\n");

			ret = 5;

			goto end;

		}

		if(!save_certs(signerfile, signers)) {

			BIO_printf(bio_err, "Error writing signers to %s\n",

								signerfile);

			ret = 2;

			ret = 5;

			goto end;

		}

		sk_X509_free(signers);

	} else if(operation == SMIME_PK7OUT) {
@@ -365,6 +378,7 @@ int MAIN(int argc, char **argv) 
		if(subject) BIO_printf(out, "Subject: %s\n", subject);

		SMIME_write_PKCS7(out, p7, in, flags);

	}

	ret = 0;

end:

	if(ret) ERR_print_errors(bio_err);

	sk_X509_pop_free(encerts, X509_free);

crypto/pkcs7/pk7_smime.c

+20 −3
Original line number Diff line number Diff line
@@ -150,6 +150,11 @@ int PKCS7_verify(PKCS7 *p7, STACK_OF(X509) *certs, X509_STORE *store, 
	BIO *p7bio;

	BIO *tmpout;



	if(!p7) {

		PKCS7err(PKCS7_F_PKCS7_VERIFY,PKCS7_R_INVALID_NULL_POINTER);

		return NULL;

	}



	if(!PKCS7_type_is_signed(p7)) {

		PKCS7err(PKCS7_F_PKCS7_VERIFY,PKCS7_R_WRONG_CONTENT_TYPE);

		return 0;
@@ -264,6 +269,11 @@ STACK_OF(X509) *PKCS7_iget_signers(PKCS7 *p7, STACK_OF(X509) *certs, int flags) 
	X509 *signer;

	int i;



	if(!p7) {

		PKCS7err(PKCS7_F_PKCS7_IGET_SIGNERS,PKCS7_R_INVALID_NULL_POINTER);

		return NULL;

	}



	if(!PKCS7_type_is_signed(p7)) {

		PKCS7err(PKCS7_F_PKCS7_IGET_SIGNERS,PKCS7_R_WRONG_CONTENT_TYPE);

		return NULL;
@@ -376,10 +386,17 @@ int PKCS7_decrypt(PKCS7 *p7, EVP_PKEY *pkey, X509 *cert, BIO *data, int flags) 
	BIO *tmpmem;

	int ret, i;

	char buf[4096];



	if(!p7) {

		PKCS7err(PKCS7_F_PKCS7_DECRYPT,PKCS7_R_INVALID_NULL_POINTER);

		return 0;

	}



	if(!PKCS7_type_is_enveloped(p7)) {

		PKCS7err(PKCS7_F_PKCS7_DECRYPT,PKCS7_R_WRONG_CONTENT_TYPE);

		return 0;

	}



	if(!X509_check_private_key(cert, pkey)) {

		PKCS7err(PKCS7_F_PKCS7_DECRYPT,

				PKCS7_R_PRIVATE_KEY_DOES_NOT_MATCH_CERTIFICATE);

crypto/pkcs7/pkcs7.h

+1 −0
Original line number Diff line number Diff line
@@ -455,6 +455,7 @@ int SMIME_text(BIO *in, BIO *out); 
#define PKCS7_R_ERROR_SETTING_CIPHER			 121

#define PKCS7_R_INTERNAL_ERROR				 102

#define PKCS7_R_INVALID_MIME_TYPE			 131

#define PKCS7_R_INVALID_NULL_POINTER			 143

#define PKCS7_R_MIME_NO_CONTENT_TYPE			 132

#define PKCS7_R_MIME_PARSE_ERROR			 133

#define PKCS7_R_MIME_SIG_PARSE_ERROR			 134

crypto/pkcs7/pkcs7err.c

+1 −0
Original line number Diff line number Diff line
@@ -105,6 +105,7 @@ static ERR_STRING_DATA PKCS7_str_reasons[]= 
{PKCS7_R_ERROR_SETTING_CIPHER            ,"error setting cipher"},

{PKCS7_R_INTERNAL_ERROR                  ,"internal error"},

{PKCS7_R_INVALID_MIME_TYPE               ,"invalid mime type"},

{PKCS7_R_INVALID_NULL_POINTER            ,"invalid null pointer"},

{PKCS7_R_MIME_NO_CONTENT_TYPE            ,"mime no content type"},

{PKCS7_R_MIME_PARSE_ERROR                ,"mime parse error"},

{PKCS7_R_MIME_SIG_PARSE_ERROR            ,"mime sig parse error"},

doc/man/smime.pod

0 → 100644
+241 −0
Original line number Diff line number Diff line 
=pod



=head1 NAME



smime - S/MIME utility



=head1 SYNOPSIS



B<openssl> B<smime>

[B<-encrypt>]

[B<-decrypt>]

[B<-sign>]

[B<-verify>]

[B<-pk7out>]

[B<-des3>]

[B<-rc2-40>]

[B<-rc2-64>]

[B<-rc2-128>]

[B<-in file>]

[B<-certfile file>]

[B<-signer file>]

[B<-recip  file>]

[B<-in file>]

[B<-inkey file>]

[B<-out file>]

[B<-to addr>]

[B<-from ad>]

[B<-subject s>]

[B<-text>]

[cert.pem]...



=head1 DESCRIPTION



The B<smime> command handles S/MIME mail. It can encrypt, decrypt, sign and

verify S/MIME messages.



=head1 COMMAND OPTIONS



There are five operation options that set the type of operation to be performed.

The meaning of the other options varies according to the operation type.



=over 4



=item B<-encrypt>



encrypt mail for the given recipient certificates. Input file is the message

to be encrypted. The output file is the encrypted mail in MIME format.



=item B<-decrypt>



decrypt mail using the supplied certificate and private key. Expects an

encrypted mail message in MIME format for the input file. The decrypted mail

is written to the output file.



=item B<-sign>



sign mail using the supplied certificate and private key. Input file is

the message to be signed. The signed message in MIME format is written

to the output file.



=item B<-verify>



verify signed mail. Expects a signed mail message on input and outputs

the signed data. Both clear text and opaque signing is supported.



=item B<-pk7out>



takes an input message and writes out a PEM encoded PKCS#7 structure.



=item B<-in filename>



the input message to be encrypted or signed or the MIME message to

be decrypted or verified.



=item B<-out filename>



the message text that has been decrypted or verified or the output MIME

format message that has been signed or verified.



=item B<-text>



this option adds plain text (text/plain) MIME headers to the supplied

message if encrypting or signing. If decrypting or verifying it strips

off text headers: if the decrypted or verified message is not of MIME 

type text/plain then an error occurs.



=item B<-CAfile file>



a file containing trusted CA certificates, only used with B<-verify>.



=item B<-CApath dir>



a directory containing trusted CA certificates, only used with

B<-verify>. This directory must be a standard certificate directory: that

is a hash of each subject name (using B<x509 -hash>) should be linked

to each certificate.



=item B<-des3 -rc2-40 -rc2-64 -rc2-128>



the encryption algorithm to use. DES (56 bits), triple DES (168 bits)

or 40, 64 or 128 bit RC2 respectively if not specified 40 bit RC2 is

used. Only used with B<-encrypt>.



=item B<-nointern>



when verifying a message normally certificates (if any) included in

the message are searched for the signing certificate. With this option

only the certificates specified in the B<-certfile> option are used.

The supplied certificates can still be used as untrusted CAs however.



=item B<-noverify>



do not verify the signers certificate of a signed message.



=item B<-nochain>



do not do chain verification of signers certfificates: that is don't

use the certificates in the signed message as untrusted CAs.



=item B<-nosigs>



don't try to verify the signatures on the message.



=item B<-nocerts>



when signing a message the signer's certificate is normally included

with this option it is excluded. This will reduce the size of the

signed message but the verifier must have a copy of the signers certificate

available locally (passed using the B<-certfile> option for example).



=item B<-noattr>



normally when a message is signed a set of attributes are included which

include the signing time and supported symmetric algorithms. With this

option they are not included.



=item B<-binary>



normally the input message is converted to "canonical" format which is

effectively using CR and LF as end of line. When this option is present

no translation occurs. This is useful when handling binary data which may

not be in MIME format.



=item B<-nodetach>



when signing a message use opaque signing: this form is more resistant

to translation by mail relays but it cannot be read by mail agents that

do not support S/MIME.  Without this option cleartext signing with

the MIME type multipart/signed is used.



=item B<-certfile file>



allows additional certificates to be specified. When signing these will

be included with the message. When verifying these will be searched for

the signers certificates. The certificates should be in PEM format.



=item B<-signer file>



the signers certificate when signing a message. If a message is

being verified then the signers certificates will be written to this

file if the verification was successful.



=item B<-recip file>



the recipients certificate when decrypting a message. This certificate

must match one of the recipients of the message or an error occurs.



=item B<-inkey file>



the private key to use when signing or decrypting. This must match the

corresponding certificate. If this option is not specified then the

private key must be included in the certificate file specified with

the B<-recip> or B<-signer> file.



=item B<cert.pem...>



one or more certificates of message recipients: used when encrypting

a message. 



=item B<-to, -from, -subject>



the relevant mail headers. These are included outside the signed

portion of a message so they may be included manually. If signing

then many S/MIME mail clients check the signers certificate's email

address matches that specified in the From: address.



=back



=head1 NOTES



The MIME message must be sent without any blank lines between the

headers and the output. Some mail programs will automatically add

a blank line. Piping the mail directly to sendmail is one way to

achieve the correct format.



A "signed and encrypted" message is one where a signed message is

then encrypted. This can be produced by encrypting an already signed

message.



This version of the program only allows one signer per message but it

will verify multiple signers on received messages. Some S/MIME clients

choke if a message contains mutiple signers. It is possible to sign

messages "in parallel" by signing an already signed message.



=head1 EXIT CODES



=over 4



=item 0



the operation was completely successful



=item 1 



an error occurred parsing the command options.



=item 2



one of the input files could not be read.



=item 3



an error occurred creating the PKCS#7 file or when reading the MIME

message.



=item 4



an error occurred decrypting or verifying the message.



=item 5



the message was verified correctly but an error occured writing out

the signers certificates.



=back



=head1 EXAMPLES



to be added.



=cut