Use inline functions to convert buffer data to scalars.

* common/host2net.h (buf16_to_ulong, buf16_to_uint): New.
(buf16_to_ushort, buf16_to_u16): New.
(buf32_to_size_t, buf32_to_ulong, buf32_to_uint, buf32_to_u32): New.
--

Commit 91b826a388 was not enough to
avoid all sign extension on shift problems.  Hanno Böck found a case
with an invalid read due to this problem.  To fix that once and for
all almost all uses of "<< 24" and "<< 8" are changed by this patch to
use an inline function from host2net.h.

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

kbx/keybox-dump.c

@@ -25,30 +25,14 @@
 
 #include "keybox-defs.h"
 #include <gcrypt.h>
+#include "host2net.h"
 
 /* Argg, we can't include ../common/util.h */
 char *bin2hexcolon (const void *buffer, size_t length, char *stringbuf);
 
+#define get32(a) buf32_to_ulong ((a))
+#define get16(a) buf16_to_ulong ((a))
 
-static ulong
-get32 (const byte *buffer)
-{
-  ulong a;
-  a =  *buffer << 24;
-  a |= buffer[1] << 16;
-  a |= buffer[2] << 8;
-  a |= buffer[3];
-  return a;
-}
-
-static ulong
-get16 (const byte *buffer)
-{
-  ulong a;
-  a =  *buffer << 8;
-  a |= buffer[1];
-  return a;
-}
 
 void
 print_string (FILE *fp, const byte *p, size_t n, int delim)

kbx/keybox-openpgp.c

@@ -36,7 +36,7 @@
 #include <gcrypt.h>
 
 #include "../common/openpgpdefs.h"
-
+#include "host2net.h"
 
 /* Assume a valid OpenPGP packet at the address pointed to by BUFBTR
    which has a maximum length as stored at BUFLEN.  Return the header
@@ -94,10 +94,8 @@ next_packet (unsigned char const **bufptr, size_t *buflen,
         {
           if (len <4 )
             return gpg_error (GPG_ERR_INV_PACKET); /* No length bytes. */
-          pktlen  = (*buf++) << 24;
-          pktlen |= (*buf++) << 16;
-          pktlen |= (*buf++) << 8;
-          pktlen |= (*buf++);
+          pktlen = buf32_to_ulong (buf);
+          buf += 4;
           len -= 4;
       }
       else /* Partial length encoding is not allowed for key packets. */

kbx/keybox-search.c

@@ -29,7 +29,7 @@
 
 #include "keybox-defs.h"
 #include <gcrypt.h>
-
+#include "host2net.h"
 
 #define xtoi_1(p)   (*(p) <= '9'? (*(p)- '0'): \
                      *(p) <= 'F'? (*(p)-'A'+10):(*(p)-'a'+10))
@@ -42,27 +42,8 @@ struct sn_array_s {
 };
 
 
-
-static inline ulong
-get32 (const byte *buffer)
-{
-  ulong a;
-  a =  *buffer << 24;
-  a |= buffer[1] << 16;
-  a |= buffer[2] << 8;
-  a |= buffer[3];
-  return a;
-}
-
-static inline ulong
-get16 (const byte *buffer)
-{
-  ulong a;
-  a =  *buffer << 8;
-  a |= buffer[1];
-  return a;
-}
-
+#define get32(a) buf32_to_ulong ((a))
+#define get16(a) buf16_to_ulong ((a))
 
 
 static inline unsigned int

kbx/keybox-update.c

@@ -28,6 +28,7 @@
 
 #include "keybox-defs.h"
 #include "../common/sysutils.h"
+#include "../common/host2net.h"
 
 #define EXTSEP_S "."
 
@@ -734,8 +735,7 @@ keybox_compress (KEYBOX_HANDLE hd)
       buffer = _keybox_get_blob_image (blob, &length);
       if (length > 4 && buffer[4] == KEYBOX_BLOBTYPE_HEADER)
         {
-          u32 last_maint = ((buffer[20] << 24) | (buffer[20+1] << 16)
-                            | (buffer[20+2] << 8) | (buffer[20+3]));
+          u32 last_maint = buf32_to_u32 (buffer+20);
 
           if ( (last_maint + 3*3600) > time (NULL) )
             {
@@ -811,7 +811,7 @@ keybox_compress (KEYBOX_HANDLE hd)
           rc = gpg_error (GPG_ERR_BUG);
           break;
         }
-      blobflags = ((buffer[pos] << 8) | (buffer[pos+1]));
+      blobflags = buf16_to_uint (buffer+pos);
       if ((blobflags & KEYBOX_FLAG_BLOB_EPHEMERAL))
         {
           /* This is an ephemeral blob. */
@@ -820,8 +820,7 @@ keybox_compress (KEYBOX_HANDLE hd)
               || size != 4)
             created_at = 0; /* oops. */
           else
-            created_at = ((buffer[pos] << 24) | (buffer[pos+1] << 16)
-                          | (buffer[pos+2] << 8) | (buffer[pos+3]));
+            created_at = buf32_to_u32 (buffer+pos);
 
           if (created_at && created_at < cut_time)
             {