6.10-stable review patch. If anyone has any objections, please let me know.
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From: Alexander Gordeev agordeev@linux.ibm.com
[ Upstream commit d7fd2941ae9a67423d1c7bee985f240e4686634f ]
When physical memory for the kernel image is allocated it does not consider extra memory required for offsetting the image start to match it with the lower 20 bits of KASLR virtual base address. That might lead to kernel access beyond its memory range.
Suggested-by: Vasily Gorbik gor@linux.ibm.com Fixes: 693d41f7c938 ("s390/mm: Restore mapping of kernel image using large pages") Signed-off-by: Alexander Gordeev agordeev@linux.ibm.com Acked-by: Vasily Gorbik gor@linux.ibm.com Signed-off-by: Vasily Gorbik gor@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/s390/boot/startup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c index 5a36d5538dae8..7797446620b64 100644 --- a/arch/s390/boot/startup.c +++ b/arch/s390/boot/startup.c @@ -446,9 +446,9 @@ void startup_kernel(void) */ kaslr_large_page_offset = __kaslr_offset & ~_SEGMENT_MASK; if (kaslr_enabled()) { - unsigned long end = ident_map_size - kaslr_large_page_offset; + unsigned long size = kernel_size + kaslr_large_page_offset;
- __kaslr_offset_phys = randomize_within_range(kernel_size, _SEGMENT_SIZE, 0, end); + __kaslr_offset_phys = randomize_within_range(size, _SEGMENT_SIZE, 0, ident_map_size); } if (!__kaslr_offset_phys) __kaslr_offset_phys = nokaslr_offset_phys;