linux-dev - Linux kernel development work

Age	Commit message (Collapse)	Author	Files	Lines
2014-11-18	x86, kaslr: Handle Gold linker for finding bss/brk	Kees Cook	1	-1/+10
	When building with the Gold linker, the .bss and .brk areas of vmlinux are shown as consecutive instead of having the same file offset. Allow for either state, as long as things add up correctly. Fixes: e6023367d779 ("x86, kaslr: Prevent .bss from overlaping initrd") Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Junjie Mao <eternal.n08@gmail.com> Link: http://lkml.kernel.org/r/20141118001604.GA25045@www.outflux.net Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-11-01	x86, kaslr: Prevent .bss from overlaping initrd	Junjie Mao	1	-0/+30
	When choosing a random address, the current implementation does not take into account the reversed space for .bss and .brk sections. Thus the relocated kernel may overlap other components in memory. Here is an example of the overlap from a x86_64 kernel in qemu (the ranges of physical addresses are presented): Physical Address 0x0fe00000 --+--------------------+ <-- randomized base / \| relocated kernel \| vmlinux.bin \| (from vmlinux.bin) \| 0x1336d000 (an ELF file) +--------------------+-- \ \| \| \ 0x1376d870 --+--------------------+ \| \| relocs table \| \| 0x13c1c2a8 +--------------------+ .bss and .brk \| \| \| 0x13ce6000 +--------------------+ \| \| \| / 0x13f77000 \| initrd \|-- \| \| 0x13fef374 +--------------------+ The initrd image will then be overwritten by the memset during early initialization: [ 1.655204] Unpacking initramfs... [ 1.662831] Initramfs unpacking failed: junk in compressed archive This patch prevents the above situation by requiring a larger space when looking for a random kernel base, so that existing logic can effectively avoids the overlap. [kees: switched to perl to avoid hex translation pain in mawk vs gawk] [kees: calculated overlap without relocs table] Fixes: 82fa9637a2 ("x86, kaslr: Select random position from e820 maps") Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Junjie Mao <eternal.n08@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Matt Fleming <matt.fleming@intel.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1414762838-13067-1-git-send-email-eternal.n08@gmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>