From: Alexander Gordeev Date: Wed, 21 Aug 2024 16:55:06 +0000 (+0200) Subject: s390/boot: Avoid possible physmem_info segment corruption X-Git-Tag: v6.10.7~55 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=a944cba5d57687b747023c3bc074fcf9c790f7df;p=thirdparty%2Fkernel%2Fstable.git s390/boot: Avoid possible physmem_info segment corruption [ 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 Fixes: 693d41f7c938 ("s390/mm: Restore mapping of kernel image using large pages") Signed-off-by: Alexander Gordeev Acked-by: Vasily Gorbik Signed-off-by: Vasily Gorbik Signed-off-by: Sasha Levin --- 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;