Add support for multiple OpenPGP signatures per package, part 1/2

Add support for multiple OpenPGP header signatures per package, base64
encoded in a string array, also known as rpm v6 signatures.

--addsign no longer deletes any signatures, it only creates and adds a
new signature if possible. --delete and --resign behave as before: they
delete ALL signatures on the package, and the latter then creates and
adds a new one.

For v6 packages this is the default signature type, but if requested,
one v4 compat signature can be created for compatible algorithms. v6
signatures on v4 packages are also supported, but have to be explicitly
requested. In that case, v3/v4 signatures are only added if none already
exist and a v4 compatible algorithm is used. v3 signatures on v6
packages are not supported (out of principle, not a technical
limitation)

On verification, if RPMTAG_OPENPGP exists then other signature tags are
ignored because they're expected to only contain compat copies of the
same content. As of now, all existing signatures must validate for
signature checking of a package to pass, further policies are to be
added later.

Fixes: #3385

docs/man/rpmsign.8.md

@@ -25,22 +25,25 @@ SIGNING PACKAGES:
 rpmsign-options
 ---------------
 
-\[**\--rpmv3**\] \[**\--fskpath ***KEY*\] \[**\--signfiles**\]
+\[**\--rpmv3**\] \[**\--rpmv4**\] \[**\--fskpath ***KEY*\] \[**\--signfiles**\]
 
 DESCRIPTION
 ===========
 
-Both of the **\--addsign** and **\--resign** options generate and insert
-new signatures for each package *PACKAGE\_FILE* given, replacing any
-existing signatures. There are two options for historical reasons, there
-is no difference in behavior currently.
+**rpmsign** **\--addsign** generates and inserts a new OpenPGP signature
+for each *PACKAGE\_FILE* given unless a signature with identical
+parameters already exists, in which case no action is taken.
+Arbitrary number of V6 signatures can be added.
+
+**rpmsign** **\--resign** generates and inserts a new OpenPGP signature
+for each *PACKAGE\_FILE*, replacing any and all previous signatures.
 
 To create a signature rpmsign needs to verify the package\'s checksum. As a
-result packages with a MD5/SHA1 checksums cannot be signed in FIPS mode.
+result V4 packages with MD5/SHA1 checksums cannot be signed in FIPS mode.
 
 **rpmsign** **\--delsign** *PACKAGE\_FILE \...*
 
-Delete all signatures from each package *PACKAGE\_FILE* given.
+Delete all OpenPGP signatures from each package *PACKAGE\_FILE* given.
 
 **rpmsign** **\--delfilesign** *PACKAGE\_FILE \...*
 
@@ -52,13 +55,40 @@ SIGN OPTIONS
 
 **\--rpmv3**
 
-:   Force RPM V3 header+payload signature addition. These are expensive
+:   Request RPM V3 header+payload signature addition on V4 packages.
+    These signatures are expensive
     and redundant baggage on packages where a separate payload digest
     exists (packages built with rpm \>= 4.14). Rpmsign will automatically
     detect the need for V3 signatures, but this option can be used to
-    force their creation if the packages must be fully signature
+    request their creation if the packages must be fully signature
     verifiable with rpm \< 4.14 or other interoperability reasons.
 
+    Has no effect when signing V6 packages.
+
+**\--rpmv4**
+
+:   Request RPM V4 header signature addition on V6 packages.
+    Useful for making V6 packages signature verifiable
+    with rpm 4.x versions.
+
+    V4 compatibility signatures are only ever added if the signing algorithm
+    is one of those known to V4: RSA, EcDSA, EdDSA (and original DSA).
+    Only one V4 signature can be present in a package, so this is
+    added only on the first **\--addsign** with a V4 compatible
+    algorithm, and ignored otherwise.
+
+    Has no effect when signing V4 packages.
+
+**\--rpmv6**
+
+:   Request RPM V6 header signature addition on V4 packages.
+
+    This generally always succeeds as there can be arbitrary number of
+    V6 signatures on a package. A V3/V4 compatibility signatures are
+    added usign the same logic as **\--rpmv4** on a V6 package.
+
+    Has no effect when signing V6 packages.
+
 **\--fskpath ***KEY*
 
 :   Used with **\--signfiles**, use file signing key *Key*.

docs/manual/tags.md

@@ -306,6 +306,7 @@ Tag Name          | Value| Type         | Description
 ------------------|------|--------------|------------
 Dsaheader         | 267  | bin          | OpenPGP DSA signature of the header (if thus signed)
 Longsigsize       | 270  | int64        | Header+payload size if > 4GB.
+Openpgp           | 278  | string array | OpenPGP signature(s) of the header, base64 encoded
 Payloaddigest     | 5092 | string array | Cryptographic digest of the compressed payload.
 Payloaddigestalgo | 5093 | int32        | ID of the payload digest algorithm.
 Payloaddigestalt  | 5097 | string array | Cryptographic digest of the uncompressed payload.
@@ -446,6 +447,7 @@ Longsigsize | Header+payload size in 64bit format
 
 Tag Name              | Value| Type         | Description
 ----------------------|------|--------------|------------
+Openpgp               |  278 | string array | All OpenPGP signature(s) in the header, including legacy ones (base64 encoded)
 Origfilenames         | 5007 | string array | Original Filenames in relocated packages.
 Providenevrs          | 5042 | string array | Formatted `name [op version]` provide dependency strings.
 Conflictnevrs         | 5044 | string array | Formatted `name [op version]` conflict dependency strings.

include/rpm/rpmsign.h

@@ -18,6 +18,9 @@ enum rpmSignFlags_e {
     RPMSIGN_FLAG_IMA		= (1 << 0),
     RPMSIGN_FLAG_RPMV3		= (1 << 1),
     RPMSIGN_FLAG_FSVERITY	= (1 << 2),
+    RPMSIGN_FLAG_RESIGN		= (1 << 3),
+    RPMSIGN_FLAG_RPMV4		= (1 << 4),
+    RPMSIGN_FLAG_RPMV6		= (1 << 5),
 };
 typedef rpmFlags rpmSignFlags;
 

include/rpm/rpmtag.h

@@ -68,6 +68,7 @@ typedef enum rpmTag_e {
     /* RPMTAG_SIG_BASE+19 reserved for RPMSIGTAG_FILESIGNATURELENGTH */
     RPMTAG_VERITYSIGNATURES	= RPMTAG_SIG_BASE+20,	/* s[] */
     RPMTAG_VERITYSIGNATUREALGO	= RPMTAG_SIG_BASE+21,	/* i */
+    RPMTAG_OPENPGP		= RPMTAG_SIG_BASE+22,	/* s[] */
     RPMTAG_SIG_TOP		= HEADER_SIGTOP,
 
     RPMTAG_NAME  		= 1000,	/* s */
@@ -455,6 +456,7 @@ typedef enum rpmSigTag_e {
     RPMSIGTAG_FILESIGNATURELENGTH	= RPMTAG_SIG_BASE + 19,
     RPMSIGTAG_VERITYSIGNATURES		= RPMTAG_VERITYSIGNATURES,
     RPMSIGTAG_VERITYSIGNATUREALGO	= RPMTAG_VERITYSIGNATUREALGO,
+    RPMSIGTAG_OPENPGP			= RPMTAG_OPENPGP,
     RPMSIGTAG_RESERVED			= RPMTAG_SIG_TOP,
 } rpmSigTag;
 

include/rpm/rpmts.h

@@ -106,6 +106,7 @@ enum rpmVSFlags_e {
     RPMVSF_NOSHA256HEADER = (1 <<  9),
     RPMVSF_NODSAHEADER	= (1 << 10),
     RPMVSF_NORSAHEADER	= (1 << 11),
+    RPMVSF_NOOPENPGP	= (1 << 12),
     /* bit(s) 12-15 unused */
     RPMVSF_NOPAYLOAD	= (1 << 16),
     RPMVSF_NOMD5	= (1 << 17),
@@ -126,13 +127,15 @@ typedef rpmFlags rpmVSFlags;
 #define	RPMVSF_MASK_NOSIGNATURES	\
   ( RPMVSF_NODSAHEADER |	\
     RPMVSF_NORSAHEADER |	\
+    RPMVSF_NOOPENPGP |	\
     RPMVSF_NODSA |		\
     RPMVSF_NORSA )
 #define	_RPMVSF_NOSIGNATURES	RPMVSF_MASK_NOSIGNATURES
 
 #define	RPMVSF_MASK_NOHEADER	\
   ( RPMVSF_NOSHA1HEADER |	\
     RPMVSF_NOSHA256HEADER |	\
+    RPMVSF_NOOPENPGP |		\
     RPMVSF_NODSAHEADER |	\
     RPMVSF_NORSAHEADER )
 #define	_RPMVSF_NOHEADER	RPMVSF_MASK_NOHEADER

lib/package.cc

@@ -58,6 +58,7 @@ static struct taglate_s {
     { RPMSIGTAG_RSA, RPMTAG_RSAHEADER, 0, 0 },
     { RPMSIGTAG_LONGSIZE, RPMTAG_LONGSIGSIZE, 1, 0 },
     { RPMSIGTAG_LONGARCHIVESIZE, RPMTAG_LONGARCHIVESIZE, 1, 0 },
+    { RPMSIGTAG_OPENPGP, RPMTAG_OPENPGP, 0, 0 },
     { 0 }
 };
 

lib/rpmvs.cc

@@ -1,5 +1,6 @@
 #include "system.h"
 
+#include <rpm/rpmbase64.h>
 #include <rpm/rpmkeyring.h>
 #include <rpm/rpmmacro.h>
 #include <rpm/rpmlog.h>
@@ -26,6 +27,7 @@ struct vfytag_s {
 };
 
 static const struct vfytag_s rpmvfytags[] = {
+    {	RPMTAG_OPENPGP,			RPM_STRING_ARRAY_TYPE,	0,	0, },
     {	RPMSIGTAG_SIZE,			RPM_BIN_TYPE,		0,	0, },
     {	RPMSIGTAG_PGP,			RPM_BIN_TYPE,		0,	0, },
     {	RPMSIGTAG_MD5,			RPM_BIN_TYPE,		0,	16, },
@@ -50,6 +52,9 @@ struct vfyinfo_s {
 };
 
 static const struct vfyinfo_s rpmvfyitems[] = {
+    {	RPMTAG_OPENPGP,			1,
+	{ RPMSIG_SIGNATURE_TYPE,	RPMVSF_NOOPENPGP,
+	(RPMSIG_HEADER),		0, 0, }, },
     {	RPMSIGTAG_SIZE,			1,
 	{ RPMSIG_OTHER_TYPE,		0,
 	(RPMSIG_HEADER|RPMSIG_PAYLOAD), 0, 0, }, },
@@ -131,14 +136,16 @@ int rpmIsValidHex(const char *str, size_t slen)
     return valid;
 }
 
-static void rpmsinfoInit(const struct vfyinfo_s *vinfo,
+static rpmRC rpmsinfoInit(const struct vfyinfo_s *vinfo,
 			  const struct vfytag_s *tinfo,
 			  rpmtd td,  const char *origin,
 			  struct rpmsinfo_s *sinfo)
 {
     rpmRC rc = RPMRC_FAIL;
     const void *data = NULL;
     rpm_count_t dlen = 0;
+    uint8_t *pkt = NULL;
+    size_t pktlen = 0;
 
     *sinfo = vinfo->vi; /* struct assignment */
     sinfo->wrapped = (vinfo->sigh == 0);
@@ -193,6 +200,16 @@ static void rpmsinfoInit(const struct vfyinfo_s *vinfo,
     }
 
     if (sinfo->type == RPMSIG_SIGNATURE_TYPE) {
+	if (td->type == RPM_STRING_ARRAY_TYPE) {
+	    if (rpmBase64Decode((const char *)data, (void **)&pkt, &pktlen)) {
+		rasprintf(&sinfo->msg, _("%s tag %u: invalid base64"),
+			origin, td->tag);
+		goto exit;
+	    }
+	    data = pkt;
+	    dlen = pktlen;
+	}
+
 	char *lints = NULL;
         int ec = pgpPrtParams2((const uint8_t *)data, dlen, PGPTAG_SIGNATURE,
 				&sinfo->sig, &lints);
@@ -234,8 +251,10 @@ static void rpmsinfoInit(const struct vfyinfo_s *vinfo,
     rc = RPMRC_OK;
 
 exit:
+    if (pkt && pkt != td->data)
+	free(pkt);
     sinfo->rc = rc;
-    return;
+    return rc;
 }
 
 static void rpmsinfoFini(struct rpmsinfo_s *sinfo)
@@ -291,11 +310,16 @@ const char *rpmsinfoDescr(struct rpmsinfo_s *sinfo)
 			rangeName(sinfo->range), t);
 		free(t);
 	    } else {
-		rasprintf(&sinfo->descr, _("%s OpenPGP %s%s %s"),
-			rangeName(sinfo->range),
-			pgpValString(PGPVAL_PUBKEYALGO, sinfo->sigalgo),
-			sinfo->alt ? " ALT" : "",
-			_("signature"));
+		if (sinfo->sigalgo) {
+		    rasprintf(&sinfo->descr, _("%s OpenPGP %s %s"),
+			    rangeName(sinfo->range),
+			    pgpValString(PGPVAL_PUBKEYALGO, sinfo->sigalgo),
+			    _("signature"));
+		} else {
+		    rasprintf(&sinfo->descr, _("%s OpenPGP %s"),
+			    rangeName(sinfo->range),
+			    _("signature"));
+		}
 	    }
 	    break;
 	}
@@ -348,7 +372,13 @@ static void rpmvsAppend(struct rpmvs_s *sis, hdrblob blob,
 
     if (!rpmsinfoDisabled(&vi->vi, sis->vsflags) && rc == RPMRC_OK) {
 	while (rpmtdNext(&td) >= 0) {
-	    rpmsinfoInit(vi, ti, &td, o, &sis->sigs[sis->nsigs]);
+	    if (!rpmsinfoInit(vi, ti, &td, o, &sis->sigs[sis->nsigs])) {
+		/* Don't bother with v3/v4 sigs when v6 sigs exist */
+		if (td.tag == RPMSIGTAG_OPENPGP) {
+		    sis->vsflags |= (RPMVSF_NODSAHEADER|RPMVSF_NORSAHEADER);
+		    sis->vsflags |= (RPMVSF_NODSA|RPMVSF_NORSA);
+		}
+	    }
 	    sis->nsigs++;
 	}
     } else {