commit ee46f6404b033f4d1312c6b52a207ec2da99d94b

[John Darrington]

Regarding Jason's latest commit to master, ("Merged changes from 
branch interaction-review"): 

I get nervous when I see memcpy used, because :

1) Its use of void * arguments circumvents type checking.
2) It offers no protection against buffer overflow.

The patch below fixes the first problem (you'll have to re-run make -f Smake).

Regarding the second problem, (specifically, I can't see anything to ensure
that result->val will be large enough to contain  the concatenated string)
I suggest an assertion similar to assert (offset < val_width);

J'


index 2697064..0716672 100644
--- a/Smake
+++ b/Smake
@@ -78,6 +78,7 @@ GNULIB_MODULES = \
        unistd \
        unistr/u8-strlen \
        unistr/u8-strncat \
+       unistr/u8-strncpy \
        unlocked-io \
        vasprintf-posix \
        vfprintf-posix \
diff --git a/src/math/interaction.c b/src/math/interaction.c
index 46d7e13..82e2bee 100644
--- a/src/math/interaction.c
+++ b/src/math/interaction.c
@@ -37,6 +37,7 @@
 #include <data/variable.h>
 #include <math/interaction.h>
 #include <string.h>
+#include "unistr.h"
 #include <xalloc.h>
 
 struct interaction_variable
@@ -150,7 +151,7 @@ interaction_value_create (const struct interaction_variable 
*var, const union va
   if (var != NULL)
     {
       int val_width = var_get_width (interaction_get_variable (var));
-      int offset;
+      int offset = 0;
 
       result = xmalloc (sizeof (*result));
       result->intr = var;
@@ -158,7 +159,6 @@ interaction_value_create (const struct interaction_variable 
*var, const union va
 
       value_init (&result->val, val_width);
 
-      offset = 0;
       result->f = 1.0;
       for (i = 0; i < n_vars; i++)
        {
@@ -174,9 +174,9 @@ interaction_value_create (const struct interaction_variable 
*var, const union va
            {
              if (var_is_alpha (var->members[i]))
                {
-                 char *val = value_str_rw (&result->val, val_width);
+                 uint8_t *val = value_str_rw (&result->val, val_width);
                   int w = var_get_width (var->members[i]);
-                  memcpy (val + offset, value_str (vals[i], w), w);
+                 u8_strncpy (val + offset, value_str (vals[i], w), w);
                   offset += w;
                }
              else if (var_is_numeric (var->members[i]))





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