agent: Allow NULL for R_PADDING, when calling scd and tpm2d.

* agent/call-scd.c (padding_info_cb): Allow NULL.
(agent_card_pkdecrypt): Likewise.
* agent/divert-scd.c (divert_pkdecrypt): Likewise.
* agent/divert-tpm2.c (divert_tpm2_pkdecrypt): Likewise.

--

It's for RSA PKCD#1 encoding if the decrypt operation removes padding
or not.  When caller knows it's not RSA, this information is no use
and it is better to allow NULL with the variable R_PADDING.

Signed-off-by: NIIBE Yutaka <[email protected]>

3 files changed, 13 insertions, 8 deletions

diff --git a/agent/call-scd.c b/agent/call-scd.c
index 91e28e68c..3da16e619 100644
--- a/agent/call-scd.c
+++ b/agent/call-scd.c
@@ -548,7 +548,8 @@ padding_info_cb (void *opaque, const char *line)
 
   if ((s=has_leading_keyword (line, "PADDING")))
     {
-      *r_padding = atoi (s);
+      if (r_padding)
+        *r_padding = atoi (s);
     }
   else if ((s=has_leading_keyword (line, "PINCACHE_PUT")))
     err = handle_pincache_put (s);
@@ -560,8 +561,8 @@ padding_info_cb (void *opaque, const char *line)
 /* Decipher INDATA using the current card.  Note that the returned
  * value is not an s-expression but the raw data as returned by
  * scdaemon.  The padding information is stored at R_PADDING with -1
- * for not known.  DESC_TEXT is an additional parameter passed to
- * GETPIN_CB.  */
+ * for not known, when it's not NULL.  DESC_TEXT is an additional
+ * parameter passed to GETPIN_CB.  */
 int
 agent_card_pkdecrypt (ctrl_t ctrl,
                       const char *keyid,
@@ -579,7 +580,8 @@ agent_card_pkdecrypt (ctrl_t ctrl,
   size_t len;
 
   *r_buf = NULL;
-  *r_padding = -1; /* Unknown.  */
+  if (r_padding)
+    *r_padding = -1; /* Unknown.  */
   rc = start_scd (ctrl);
   if (rc)
     return rc;
diff --git a/agent/divert-scd.c b/agent/divert-scd.c
index 4a2bebffa..d7454d968 100644
--- a/agent/divert-scd.c
+++ b/agent/divert-scd.c
@@ -380,7 +380,7 @@ divert_pksign (ctrl_t ctrl, const unsigned char *grip,
 /* Decrypt the value given as an s-expression in CIPHER using the
    key identified by SHADOW_INFO and return the plaintext in an
    allocated buffer in R_BUF.  The padding information is stored at
-   R_PADDING with -1 for not known.  */
+   R_PADDING with -1 for not known, when it's not NULL.  */
 int
 divert_pkdecrypt (ctrl_t ctrl,
                   const unsigned char *grip,
@@ -399,7 +399,8 @@ divert_pkdecrypt (ctrl_t ctrl,
 
   bin2hex (grip, 20, hexgrip);
 
-  *r_padding = -1;
+  if (r_padding)
+    *r_padding = -1;
   s = cipher;
   if (*s != '(')
     return gpg_error (GPG_ERR_INV_SEXP);
diff --git a/agent/divert-tpm2.c b/agent/divert-tpm2.c
index 2496d091a..6ebb9ef78 100644
--- a/agent/divert-tpm2.c
+++ b/agent/divert-tpm2.c
@@ -106,7 +106,8 @@ divert_tpm2_pkdecrypt (ctrl_t ctrl,
   const unsigned char *s;
   size_t n;
 
-  *r_padding = -1;
+  if (r_padding)
+    *r_padding = -1;
 
   s = cipher;
   if (*s != '(')
@@ -125,7 +126,8 @@ divert_tpm2_pkdecrypt (ctrl_t ctrl,
     return gpg_error (GPG_ERR_INV_SEXP);
   if (smatch (&s, n, "rsa"))
     {
-      *r_padding = 0;
+      if (r_padding)
+        *r_padding = 0;
       if (*s != '(')
         return gpg_error (GPG_ERR_UNKNOWN_SEXP);
       s++;