Allow checking for signature times and use in merging

Add support for pulling out the creation time of a signature, then use
this information when we're merging key signatures. This allows for
updating of signatures (eg key preferences) or adding new signatures eg
with later expiry dates. As reported in Debian bug #410796

diff --git a/decodekey.c b/decodekey.c
index efffad7d7863a7e310647113801fb21ba545c22f..3a6e075d53544882425981dbac7bce034b5c7817 100644 (file)
--- a/decodekey.c
+++ b/decodekey.c
@@ -22,13 +22,15 @@
 /*
  *     parse_subpackets - Parse the subpackets of a Type 4 signature.
  *     @data: The subpacket data.
- *      @keyid: A pointer to where we should return the keyid.
+ *     @keyid: A pointer to where we should return the keyid.
+ *     @creationtime: A pointer to where we should return the creation time.
  *
  *     This function parses the subkey data of a Type 4 signature and fills
  *     in the supplied variables. It also returns the length of the data
- *     processed.
+ *     processed. If the value of any piece of data is not desired a NULL
+ *     can be passed instead of a pointer to a storage area for that value.
  */
-int parse_subpackets(unsigned char *data, uint64_t *keyid)
+int parse_subpackets(unsigned char *data, uint64_t *keyid, time_t *creation)
 {
        int offset = 0;
        int length = 0;
@@ -56,8 +58,17 @@ int parse_subpackets(unsigned char *data, uint64_t *keyid)
                switch (data[offset] & 0x7F) {
                case 2:
                        /*
-                        * Signature creation time. Might want to output this?
+                        * Signature creation time.
                         */
+                       if (creation != NULL) {
+                               *creation = data[offset + packetlen - 4];
+                               *creation <<= 8;
+                               *creation = data[offset + packetlen - 3];
+                               *creation <<= 8;
+                               *creation = data[offset + packetlen - 2];
+                               *creation <<= 8;
+                               *creation = data[offset + packetlen - 1];
+                       }
                        break;
                case 3:
                        /*
@@ -65,21 +76,23 @@ int parse_subpackets(unsigned char *data, uint64_t *keyid)
                         */
                        break;
                case 16:
-                       *keyid = data[offset+packetlen - 8];
-                       *keyid <<= 8;
-                       *keyid += data[offset+packetlen - 7];
-                       *keyid <<= 8;
-                       *keyid += data[offset+packetlen - 6];
-                       *keyid <<= 8;
-                       *keyid += data[offset+packetlen - 5];
-                       *keyid <<= 8;
-                       *keyid += data[offset+packetlen - 4];
-                       *keyid <<= 8;
-                       *keyid += data[offset+packetlen - 3];
-                       *keyid <<= 8;
-                       *keyid += data[offset+packetlen - 2];
-                       *keyid <<= 8;
-                       *keyid += data[offset+packetlen - 1];
+                       if (keyid != NULL) {
+                               *keyid = data[offset+packetlen - 8];
+                               *keyid <<= 8;
+                               *keyid += data[offset+packetlen - 7];
+                               *keyid <<= 8;
+                               *keyid += data[offset+packetlen - 6];
+                               *keyid <<= 8;
+                               *keyid += data[offset+packetlen - 5];
+                               *keyid <<= 8;
+                               *keyid += data[offset+packetlen - 4];
+                               *keyid <<= 8;
+                               *keyid += data[offset+packetlen - 3];
+                               *keyid <<= 8;
+                               *keyid += data[offset+packetlen - 2];
+                               *keyid <<= 8;
+                               *keyid += data[offset+packetlen - 1];
+                       }
                        break;
                case 20:
                        /*
@@ -138,42 +151,55 @@ struct ll *keysigs(struct ll *curll,
 }
 
 /**
- *     sig_keyid - Return the keyid for a given OpenPGP signature packet.
- *     @packet: The signature packet.
+ *     sig_info - Get info on a given OpenPGP signature packet
+ *     @packet: The signature packet
+ *     @keyid: A pointer for where to return the signature keyid
+ *     @creation: A pointer for where to return the signature creation time
  *
- *     Returns the keyid for the supplied signature packet.
+ *     Gets any info about a signature packet; parses the subpackets for a v4
+ *     key or pulls the data directly from v2/3. NULL can be passed for any
+ *     values which aren't cared about.
  */
-uint64_t sig_keyid(struct openpgp_packet *packet)
+void sig_info(struct openpgp_packet *packet, uint64_t *keyid, time_t *creation)
 {
        int length = 0;
-       uint64_t keyid = 0;
        
        if (packet != NULL) {
-               keyid = 0;
                switch (packet->data[0]) {
                case 2:
                case 3:
-                       keyid = packet->data[7];
-                       keyid <<= 8;
-                       keyid += packet->data[8];
-                       keyid <<= 8;
-                       keyid += packet->data[9];
-                       keyid <<= 8;
-                       keyid += packet->data[10];
-                       keyid <<= 8;
-                       keyid += packet->data[11];
-                       keyid <<= 8;
-                       keyid += packet->data[12];
-                       keyid <<= 8;
-                       keyid += packet->data[13];
-                       keyid <<= 8;
-                       keyid += packet->data[14];
+                       if (keyid != NULL) {
+                               *keyid = packet->data[7];
+                               *keyid <<= 8;
+                               *keyid += packet->data[8];
+                               *keyid <<= 8;
+                               *keyid += packet->data[9];
+                               *keyid <<= 8;
+                               *keyid += packet->data[10];
+                               *keyid <<= 8;
+                               *keyid += packet->data[11];
+                               *keyid <<= 8;
+                               *keyid += packet->data[12];
+                               *keyid <<= 8;
+                               *keyid += packet->data[13];
+                               *keyid <<= 8;
+                               *keyid += packet->data[14];
+                       }
+                       if (creation != NULL) {
+                               *creation = packet->data[3];
+                               *creation <<= 8;
+                               *creation = packet->data[4];
+                               *creation <<= 8;
+                               *creation = packet->data[5];
+                               *creation <<= 8;
+                               *creation = packet->data[6];
+                       }
                        break;
                case 4:
                        length = parse_subpackets(&packet->data[4],
-                                       &keyid);
+                                       keyid, creation);
                        parse_subpackets(&packet->data[length + 4],
-                                       &keyid);
+                                       keyid, creation);
                        /*
                         * Don't bother to look at the unsigned packets.
                         */
@@ -183,9 +209,25 @@ uint64_t sig_keyid(struct openpgp_packet *packet)
                }
        }
 
+       return;
+}
+
+/**
+ *     sig_keyid - Return the keyid for a given OpenPGP signature packet.
+ *     @packet: The signature packet.
+ *
+ *     Returns the keyid for the supplied signature packet.
+ */
+uint64_t sig_keyid(struct openpgp_packet *packet)
+{
+       uint64_t keyid = 0;
+
+       sig_info(packet, &keyid, NULL);
+
        return keyid;
 }
 
+
 /*
  * TODO: Abstract out; all our linked lists should be generic and then we can
  * llsize them.

diff --git a/decodekey.h b/decodekey.h
index 57bf68074a66c28926463db2e9cc284904d27ecf..987c3fc7d7c26c51c46c09c5e7bb4f8a07a10b32 100644 (file)
--- a/decodekey.h
+++ b/decodekey.h
@@ -23,6 +23,18 @@
 struct ll *keysigs(struct ll *curll,
                struct openpgp_packet_list *sigs);
 
+/**
+ *     sig_info - Get info on a given OpenPGP signature packet
+ *     @packet: The signature packet
+ *     @keyid: A pointer for where to return the signature keyid
+ *     @creation: A pointer for where to return the signature creation time
+ *
+ *     Gets any info about a signature packet; parses the subpackets for a v4
+ *     key or pulls the data directly from v2/3. NULL can be passed for any
+ *     values which aren't cared about.
+ */
+void sig_info(struct openpgp_packet *packet, uint64_t *keyid, time_t *creation);
+
 /**
  *     sig_keyid - Return the keyid for a given OpenPGP signature packet.
  *     @packet: The signature packet.

diff --git a/merge.c b/merge.c
index 87f45fca642cba3c1e1eaec9a5788181b5c828b9..be97eb4782b32f5550f8f63a6db0db87d858c9ac 100644 (file)
--- a/merge.c
+++ b/merge.c
@@ -43,15 +43,19 @@ bool compare_packets(struct openpgp_packet *a, struct openpgp_packet *b)
  */
 bool compare_signatures(struct openpgp_packet *a, struct openpgp_packet *b)
 {
+       uint64_t a_keyid, b_keyid;
+       time_t a_creation, b_creation;
+
        if (a->data[0] != b->data[0]) {
                /* Different signature versions, so not the same */
                return false;
        } else if (a->data[0] == 4 && a->data[1] != b->data[1]) {
                /* Type 4 signature, but different types */
                return false;
-       /* TODO: Check signature time? */
        } else {
-               return (sig_keyid(a) == sig_keyid(b));
+               sig_info(a, &a_keyid, &a_creation);
+               sig_info(b, &b_keyid, &b_creation);
+               return (a_creation == b_creation) && (a_keyid == b_keyid);
        }
 }