Improve robustness and help lint.

* cipher/rsa.c (rsa_encrypt): Check for !DATA.
* cipher/md.c (search_oid): Check early for !OID.
(md_copy): Use gpg_err_code_from_syserror.  Replace chains of if(!err)
tests.
* cipher/cipher.c (search_oid): Check early for !OID.
* src/misc.c (do_printhex): Allow for BUFFER==NULL even with LENGTH>0.
* mpi/mpicoder.c (onecompl): Allow for A==NULL to help static
analyzers.
--

The change for md_copy is to help static analyzers which have no idea
that gpg_err_code_from_syserror will never return 0.  A gcc attribute
returns_nonzero would be a nice to have.

Some changes are due to the fact the macros like mpi_is_immutable
gracefully handle a NULL arg but a static analyzer the considers that
the function allows for a NULL arg.

Signed-off-by: Werner Koch <wk@gnupg.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/misc.c b/src/misc.c
index ac64d703..413d7d82 100644
--- a/src/misc.c
+++ b/src/misc.c
@@ -291,7 +291,7 @@ do_printhex (const char *text, const char *text2,
           log_debug ("%*s  ", (int)strlen(text), "");
         }
     }
-  if (length)
+  if (length && buffer)
     {
       const unsigned char *p = buffer;
       for (; length--; p++)