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-rw-r--r--pith/smime.c159
1 files changed, 85 insertions, 74 deletions
diff --git a/pith/smime.c b/pith/smime.c
index e34cfb6b..8d7bbd27 100644
--- a/pith/smime.c
+++ b/pith/smime.c
@@ -56,7 +56,6 @@ static int app_RAND_write_file(const char *file);
static void smime_init(void);
static const char *openssl_error_string(void);
static void create_local_cache(char *base, BODY *b);
-static BIO *raw_part_to_bio(long msgno, const char *section);
static long rfc822_output_func(void *b, char *string);
static int load_private_key(PERSONAL_CERT *pcert);
static void setup_pkcs7_body_for_signature(BODY *b, char *description,
@@ -1469,50 +1468,6 @@ end:
/*
- * Plonk the contents (mime headers and body) of the given
- * section of a message to a BIO_s_mem BIO object.
- */
-static BIO *
-raw_part_to_bio(long msgno, const char *section)
-{
- unsigned long len;
- char *text;
- BIO *bio;
-
- bio = BIO_new(BIO_s_mem());
-
- if(bio){
-
- (void) BIO_reset(bio);
-
- /* First grab headers of the chap */
- text = mail_fetch_mime(ps_global->mail_stream, msgno, (char*) section, &len, 0);
-
- if(text){
- BIO_write(bio, text, len);
-
- /** Now grab actual body */
- text = mail_fetch_body (ps_global->mail_stream, msgno, (char*) section, &len, 0);
- if(text){
- BIO_write(bio, text, len);
- }
- else{
- BIO_free(bio);
- bio = NULL;
- }
-
- }
- else{
- BIO_free(bio);
- bio = NULL;
- }
- }
-
- return bio;
-}
-
-
-/*
Get (and decode) the body of the given section of msg
*/
static STORE_S*
@@ -1684,6 +1639,40 @@ free_smime_body_sparep(void **sparep)
}
}
+/* Big comment, explaining the mess that exists out there
+
+ When Alpine sends a message, it constructs that message, computes the
+ signature, but then it forgets the message it signed and reconstructs it
+ again. Since it signs a message containing a notice about "mime aware
+ tools", but it does not send that we do not include that in the part that
+ is signed, and that takes care of much of the problems.
+
+ Another problem is what is received from the servers. All servers tested
+ seem to transmit the message that was signed intact and Alpine can check
+ the signature correctly. That is not a problem. The problem arises when
+ the message includes attachments. In this case different servers send
+ different things, so it will be up to us to figure out what is the text
+ that was actually signed. Confused? here is the story:
+
+ When a message containing and attachment is sent by Alpine, UW-IMAP,
+ Panda-IMAP, Gmail, and local reading of folders send exactly the message
+ that was sent by Alpine, but GMX.com, Exchange, and probably other servers
+ add a trailing \r\n in the message, so when validating the signature,
+ these messages will not validate. There are several things that can be
+ done.
+
+ 1. Add a trailing \r\n to any message that contains attachments, sign that
+ and send that. In this way, all messages will validate with all
+ servers.
+
+ 2. Compatibility mode: If a message has an attachment, contains a trailing
+ \r\n and does not validate (sent by an earlier version of Alpine),
+ remove the trailing \r\n and try to revalidate again.
+
+ 3. We do not add \r\n to validate a message that we sent, because that
+ would only work in Alpine, and not in any other client. That would not
+ be a good thing to do.
+ */
/*
* Given a multipart body of type multipart/signed, attempt to verify it.
@@ -1696,55 +1685,77 @@ do_detached_signature_verify(BODY *b, long msgno, char *section)
BIO *in = NULL;
PART *p;
int result, modified_the_body = 0;
- char newSec[100];
+ unsigned long mimelen, bodylen;
+ char newSec[100], *mimetext, *bodytext;
char *what_we_did;
dprint((9, "do_detached_signature_verify(msgno=%ld type=%d subtype=%s section=%s)", msgno, b->type, b->subtype ? b->subtype : "NULL", (section && *section) ? section : (section != NULL) ? "Top" : "NULL"));
smime_init();
snprintf(newSec, sizeof(newSec), "%s%s1", section ? section : "", (section && *section) ? "." : "");
- in = raw_part_to_bio(msgno, newSec);
- if(in){
+ mimetext = mail_fetch_mime(ps_global->mail_stream, msgno, (char*) newSec, &mimelen, 0);
- snprintf(newSec, sizeof(newSec), "%s%s2", section ? section : "", (section && *section) ? "." : "");
- p7 = get_pkcs7_from_part(msgno, newSec);
+ if(mimetext)
+ bodytext = mail_fetch_body (ps_global->mail_stream, msgno, (char*) newSec, &bodylen, 0);
- if(!p7)
- goto end;
+ if (mimetext == NULL || bodytext == NULL)
+ return modified_the_body;
- result = do_signature_verify(p7, in, NULL);
+ snprintf(newSec, sizeof(newSec), "%s%s2", section ? section : "", (section && *section) ? "." : "");
- if(b->subtype)
- fs_give((void**) &b->subtype);
+ if((p7 = get_pkcs7_from_part(msgno, newSec)) == NULL)
+ return modified_the_body;
- b->subtype = cpystr(OUR_PKCS7_ENCLOSURE_SUBTYPE);
- b->encoding = ENC8BIT;
+ /* first try with what get got */
+ if((in = BIO_new(BIO_s_mem())) == NULL)
+ return modified_the_body;
- if(b->description)
- fs_give ((void**) &b->description);
+ (void) BIO_reset(in);
+ BIO_write(in, mimetext, mimelen);
+ BIO_write(in, bodytext, bodylen);
- what_we_did = result ? _("This message was cryptographically signed.") :
- _("This message was cryptographically signed but the signature could not be verified.");
+ /* Try compatibility with the past and check if this message
+ validates when we remove the last two characters
+ */
+ if(((result = do_signature_verify(p7, in, NULL)) == 0)
+ && bodylen > 2
+ && (strncmp(bodytext+bodylen-2,"\r\n", 2) == 0)){
+ BIO_free(in);
+ if((in = BIO_new(BIO_s_mem())) == NULL)
+ return modified_the_body;
- b->description = cpystr(what_we_did);
+ (void) BIO_reset(in);
+ BIO_write(in, mimetext, mimelen);
+ BIO_write(in, bodytext, bodylen-2);
- b->sparep = p7;
- p7 = NULL;
+ result = do_signature_verify(p7, in, NULL);
+ }
- p = b->nested.part;
-
- /* p is signed plaintext */
- if(p && p->next)
- mail_free_body_part(&p->next); /* hide the pkcs7 from the viewer */
+ BIO_free(in);
+ if(b->subtype)
+ fs_give((void**) &b->subtype);
- BIO_free(in);
+ b->subtype = cpystr(OUR_PKCS7_ENCLOSURE_SUBTYPE);
+ b->encoding = ENC8BIT;
- modified_the_body = 1;
- }
+ if(b->description)
+ fs_give ((void**) &b->description);
-end:
- PKCS7_free(p7);
+ what_we_did = result ? _("This message was cryptographically signed.") :
+ _("This message was cryptographically signed but the signature could not be verified.");
+
+ b->description = cpystr(what_we_did);
+
+ b->sparep = p7;
+
+ p = b->nested.part;
+
+ /* p is signed plaintext */
+ if(p && p->next)
+ mail_free_body_part(&p->next); /* hide the pkcs7 from the viewer */
+
+ modified_the_body = 1;
return modified_the_body;
}
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