Provide a facility to autogenerate the name of PGP keys from the contents of
the payload.  If add_key() is given a blank description, a description is
constructed from the last user ID packet in the payload data plus the last 8
hex digits of the key ID.  For instance:

        keyctl padd crypto "" @s </tmp/key.pub

might create a key with a constructed description that can be seen in
/proc/keys:

2f674b96 I--Q---     1 perm 39390000     0     0 crypto    Sample kernel key 
31f0ae93: PGP.RSA 31f0ae93 []

Signed-off-by: David Howells <dhowe...@redhat.com>
---

 security/keys/crypto/pgp_public_key.c |   64 +++++++++++++++++++++++++++------
 1 file changed, 53 insertions(+), 11 deletions(-)


diff --git a/security/keys/crypto/pgp_public_key.c 
b/security/keys/crypto/pgp_public_key.c
index c260e02..2347ecd 100644
--- a/security/keys/crypto/pgp_public_key.c
+++ b/security/keys/crypto/pgp_public_key.c
@@ -52,6 +52,9 @@ struct pgp_key_data_parse_context {
        struct crypto_key_subtype *subtype;
        char *fingerprint;
        void *payload;
+       const char *user_id;
+       size_t user_id_len;
+       size_t fingerprint_len;
 };
 
 /*
@@ -166,6 +169,7 @@ static int pgp_generate_fingerprint(struct 
pgp_key_data_parse_context *ctx,
        if (ret < 0)
                goto cleanup_raw_fingerprint;
 
+       ctx->fingerprint_len = digest_size * 2;
        fingerprint = kmalloc(digest_size * 2 + 1, GFP_KERNEL);
        if (!fingerprint)
                goto cleanup_raw_fingerprint;
@@ -212,6 +216,13 @@ static int pgp_process_public_key(struct pgp_parse_context 
*context,
 
        kenter(",%u,%u,,%zu", type, headerlen, datalen);
 
+       if (type == PGP_PKT_USER_ID) {
+               ctx->user_id = data;
+               ctx->user_id_len = datalen;
+               kleave(" = 0 [user ID]");
+               return 0;
+       }
+
        if (ctx->subtype) {
                kleave(" = -ENOKEY [already]");
                return -EBADMSG;
@@ -297,21 +308,44 @@ static int pgp_key_preparse(struct key_preparsed_payload 
*prep)
 
        kenter("");
 
+       memset(&ctx, 0, sizeof(ctx));
        ctx.pgp.types_of_interest =
-               (1 << PGP_PKT_PUBLIC_KEY) | (1 << PGP_PKT_PUBLIC_SUBKEY);
+               (1 << PGP_PKT_PUBLIC_KEY) | (1 << PGP_PKT_PUBLIC_SUBKEY) |
+               (1 << PGP_PKT_USER_ID);
        ctx.pgp.process_packet = pgp_process_public_key;
-       ctx.subtype = NULL;
-       ctx.fingerprint = NULL;
-       ctx.payload = NULL;
 
        ret = pgp_parse_packets(prep->data, prep->datalen, &ctx.pgp);
-       if (ret < 0) {
-               if (ctx.payload)
-                       ctx.subtype->destroy(ctx.payload);
-               if (ctx.subtype)
-                       module_put(ctx.subtype->owner);
-               kfree(ctx.fingerprint);
-               return ret;
+       if (ret < 0)
+               goto error;
+
+       if (ctx.user_id && ctx.user_id_len > 0) {
+               /* Propose a description for the key (user ID without the 
comment) */
+               size_t ulen = ctx.user_id_len, flen = ctx.fingerprint_len;
+               const char *p;
+
+               p = memchr(ctx.user_id, '(', ulen);
+               if (p) {
+                       /* Remove the comment */
+                       do {
+                               p--;
+                       } while (*p == ' ' && p > ctx.user_id);
+                       if (*p != ' ')
+                               p++;
+                       ulen = p - ctx.user_id;
+               }
+
+               if (ulen > 255 - 9)
+                       ulen = 255 - 9;
+               prep->description = kmalloc(ulen + 1 + 8 + 1, GFP_KERNEL);
+               ret = -ENOMEM;
+               if (!prep->description)
+                       goto error;
+               memcpy(prep->description, ctx.user_id, ulen);
+               prep->description[ulen] = ' ';
+               memcpy(prep->description + ulen + 1,
+                      ctx.fingerprint + flen - 8, 8);
+               prep->description[ulen + 9] = 0;
+               pr_debug("desc '%s'\n", prep->description);
        }
 
        prep->type_data[0] = ctx.subtype;
@@ -319,6 +353,14 @@ static int pgp_key_preparse(struct key_preparsed_payload 
*prep)
        prep->payload = ctx.payload;
        prep->quotalen = prep->datalen;
        return 0;
+
+error:
+       if (ctx.payload)
+               ctx.subtype->destroy(ctx.payload);
+       if (ctx.subtype)
+               module_put(ctx.subtype->owner);
+       kfree(ctx.fingerprint);
+       return ret;
 }
 
 static struct crypto_key_parser pgp_key_parser = {

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