Move the signal handlers into a VDSO page rather than keeping them in
the vectors page. This allows us to place them randomly within this
page, and also map the page at a random location within userspace
further protecting these code fragments from ROP attacks. The new
VDSO page is also poisoned in the same way as the vector page.
Change-Id: Ic45bb26efb1f00de0a025d36fc15dbd6580dc7de
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Git-commit: 48be69a026b2c17350a5ef18a1959a919f60be7d
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
[joonwoop@codeaurora.org: fixed merge conflict]
CRs-fixed: 561044
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
The signal restarting code was placed on the user stack when OABI
compatibility is enabled. Unfortunately, with an EABI NX executable,
this results in an attempt to run code from the non-executable stack,
which segfaults the application.
Fix this by placing the code in the vectors page, along side the
signal return code, and directing the application to that code.
Reported-by: saeed bishara <saeed.bishara@gmail.com>
Tested-by: saeed bishara <saeed.bishara@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The high page vector (0xFFFF0000) does not supported in nommu mode.
This patch allows the vectors to be 0x00000000 or the begining of DRAM
in nommu mode.
Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Nicolas Pitre
The signal return path consists of user code provided by the kernel.
Since a syscall is used, it has to be updated to work with EABI.
Noticed by Daniel Jacobowitz.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Move the signal return code into the vector page instead of placing
it on the user mode stack, which will allow us to avoid flushing
the instruction cache on signals, as well as eventually allowing
non-exec stack.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Francescodario Cuzzocrea
Russell King
Hyok S. Choi
Nicolas Pitre
Russell King