libgdk-pixbuf2 executable stack bit

[John Moser]

Binary package hint: libgdk-pixbuf2

libgdk-pixbuf2 has an executable stack:

bluefox@icebox:/tmp/x/gdkpixbuf/gdk-pixbuf-0.22.0$ scanelf -qeR /usr/lib/libgdk_pixbuf.so.2
RWX --- --- /usr/lib/libgdk_pixbuf.so.2

Removing this can be corrected in one of two ways:

A) Build without MMX by fixing debian/rules to pass "--disable-mmx" to ./configure (currently it does NOT)

B) Add to the end of the following source files:

 gdk-pixbuf/pixops/composite_line_22_4a4_mmx.S
 gdk-pixbuf/pixops/composite_line_color_22_4a4_mmx.S
 gdk-pixbuf/pixops/have_mmx.S
 gdk-pixbuf/pixops/scale_line_22_33_mmx.S

The following code block:

#ifdef __ELF__
.section .note.GNU-stack,"",%progbits
#endif

Either of these works fine. The second path may warrent a look at the assembly code to make sure it doesn't try to execute the stack; but in general, this doesn't happen. The output .o file simply lacks a .note.GNU-stack segment and to be "safe" gcc assumes an executable stack is necessary[1].

I am personally partial to removing assembly code anyway, so I prefer option (A).

Result of option (A):

bluefox@icebox:/tmp/x/gdkpixbuf/gdk-pixbuf-0.22.0$ scanelf -Rte debian/libgdk-pixbuf2/usr/lib/
 TYPE STK/REL/PTL TEXTREL FILE
ET_DYN RW- --- RW- - debian/libgdk-pixbuf2/usr/lib/libgdk_pixbuf.so.2.0.0
ET_DYN RW- --- RW- - debian/libgdk-pixbuf2/usr/lib/libgdk_pixbuf_xlib.so.2.0.0

Result of option (B):

bluefox@icebox:/tmp/x/gdkpixbuf/gdk-pixbuf-0.22.0$ scanelf -Rte debian/libgdk-pixbuf2/usr/lib/
 TYPE STK/REL/PTL TEXTREL FILE
ET_DYN RW- --- RW- - debian/libgdk-pixbuf2/usr/lib/libgdk_pixbuf.so.2.0.0
ET_DYN RW- --- RW- - debian/libgdk-pixbuf2/usr/lib/libgdk_pixbuf_xlib.so.2.0.0

Pick one.

[1] http://www.gentoo.org/proj/en/hardened/gnu-stack.xml

[John Moser (nigelenki)]

Oh yeah, I should mention, Option (B) should be sent upstream at some point. I haven't done this.

[Jérôme Guelfucci (jerome-guelfucci-deactivatedaccount)]

Closed upstream so I close it here, feel free to reopen.