Re: [libsmi] Null pointer dereference in parser-smi.y

11 Apr 2015


      On 11/04/2015 17:51, Tomalak Geret'kal wrote:
...
Hi
I've been trying to build libsmi trunk for 
x86_64-w64-mingw32 and I've encountered a problem. I don't 
know whether the MIB I'm trying to load has some 
invalidity, though it's a CISCO MIB and smilint accepts 
it. Presumably I have done something wrong elsewhere and 
will look into that separately.
Regardless, the particular segfault I received led me to 
this code (lib/parser-smi.y:2420), which seems strange:
            if (!($11))
                smiPrintError(thisParserPtr, 

ERR_INTERNAL);
                /*
                 * Otherwise, we have to allocate a
                 * new Type struct, inherited from $10.
                 */
                $$ = duplicateType($11, 0, thisParserPtr);
duplicateType (lib/smi-data.c:2404) unconditionally 
dereferences its first parameter so, since $11 is invalid 
in this block, the call to duplicateType is broken.
What is this code supposed to be instead?
Best regards
Tom
Could it be as simple as
-   $$ = duplicateType($11, 0, thisParserPtr);
+  $$ = duplicateType($10, 0, thisParserPtr);
?
If so, do I need to make the same change in 
lib/parser-smi.c? Or will that be done for me during the build?
Best regards
Tom