forked from luck/tmp_suning_uos_patched
1bea03b44e
commit ba6e31af2be96c4d0536f2152ed6f7b6c11bca47 upstream. RSB fill sequence does not have any protection for miss-prediction of conditional branch at the end of the sequence. CPU can speculatively execute code immediately after the sequence, while RSB filling hasn't completed yet. #define __FILL_RETURN_BUFFER(reg, nr, sp) \ mov $(nr/2), reg; \ 771: \ ANNOTATE_INTRA_FUNCTION_CALL; \ call 772f; \ 773: /* speculation trap */ \ UNWIND_HINT_EMPTY; \ pause; \ lfence; \ jmp 773b; \ 772: \ ANNOTATE_INTRA_FUNCTION_CALL; \ call 774f; \ 775: /* speculation trap */ \ UNWIND_HINT_EMPTY; \ pause; \ lfence; \ jmp 775b; \ 774: \ add $(BITS_PER_LONG/8) * 2, sp; \ dec reg; \ jnz 771b; <----- CPU can miss-predict here. Before RSB is filled, RETs that come in program order after this macro can be executed speculatively, making them vulnerable to RSB-based attacks. Mitigate it by adding an LFENCE after the conditional branch to prevent speculation while RSB is being filled. Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com> Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
||
---|---|---|
arch | ||
block | ||
certs | ||
crypto | ||
Documentation | ||
drivers | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
LICENSES | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | ||
.cocciconfig | ||
.get_maintainer.ignore | ||
.gitattributes | ||
.gitignore | ||
.mailmap | ||
COPYING | ||
CREDITS | ||
Kbuild | ||
Kconfig | ||
MAINTAINERS | ||
Makefile | ||
README |
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.