/ 
Tk804.025_beta2
/ mkVFunc
Security Advisories (5)
CVE-2006-4484 (2008-10-01)

Buffer overflow in the LWZReadByte_ function in the GD extension in allows remote attackers to have an unknown impact via a GIF file with input_code_size greater than MAX_LWZ_BITS, which triggers an overflow when initializing the table array.

CVE-2007-4769 (2008-01-09)

The regular expression parser in TCL before 8.4.17, as used in PostgreSQL 8.2 before 8.2.6, 8.1 before 8.1.11, 8.0 before 8.0.15, and 7.4 before 7.4.19, allows remote authenticated users to cause a denial of service (backend crash) via an out-of-bounds backref number.

CVE-2003-0107 (2003-03-07)

Buffer overflow in the gzprintf function in zlib 1.1.4, when zlib is compiled without vsnprintf or when long inputs are truncated using vsnprintf, allows attackers to cause a denial of service or possibly execute arbitrary code.

CVE-2007-4772 (2008-01-09)

The regular expression parser in TCL before 8.4.17, as used in PostgreSQL 8.2 before 8.2.6, 8.1 before 8.1.11, 8.0 before 8.0.15, and 7.4 before 7.4.19, allows context-dependent attackers to cause a denial of service (infinite loop) via a crafted regular expression.

CVE-2007-6067 (2008-01-09)

Algorithmic complexity vulnerability in the regular expression parser in TCL before 8.4.17, as used in PostgreSQL 8.2 before 8.2.6, 8.1 before 8.1.11, 8.0 before 8.0.15, and 7.4 before 7.4.19, allows remote authenticated users to cause a denial of service (memory consumption) via a crafted "complex" regular expression with doubly-nested states.

NAME

mkVFunc - Support for "nested" dynamic loading

SYNOPSIS

mkVFunc xxx.h

DESCRIPTION

perl/Tk is designed so that Tk can be dynamically loaded 'on top of' perl. That is the easy bit. What it also does is allow Tk::Xxxx to be dynamically loaded 'on top of' the perl/Tk composite. Thus when you 'require Tk::HList' the shared object .../HList.so needs to be able to call functions defined in perl and functions defined in loadable .../Tk.so . Now functions in 'base executable' are a well known problem, and are solved by DynaLoader. However most of dynamic loading schemes cannot handle one loadable calling another loadable.

Thus what Tk does is build a table of functions that should be callable. This table is auto-generated from the .h file by looking for 'extern' (and EXTERN which is #defined to 'extern'). Thus any function marked as 'extern' is 'referenced' by the table. The address of the table is then stored in a perl variable when Tk is loaded. When HList is loaded it looks in the perl variable (via functions in perl - the 'base executable') to get the address of the table.

The same utility that builds the table also builds a set of #define's. HList.c (and any other .c files which comprise HList) #include these #define's. So that

Tk_SomeFunc(x,y,z)

Is actually compiled as

(*TkVptr->V_Tk_SomeFunc)(x,y,z)

Where Tk_ptr is pointer to the table.

See:

Tk-b*/pTk/mkVFunc - perl script that produces tables
         /tk.h        - basis from which table is generated
         /tk.m        - #define's to include in sub-extension
         /tk_f.h      - #included both sides.
         /tk_f.c      - Actual table definition.
         /tk.t        - 'shared' set of macros which produce table
                        included in tk_f.c and tk_f.h
         /tkVMacro.h  - Wrapper to include *.m files

In addition to /tk* there are /tkInt*, /Lang* and /tix*