x86/mm/init/32: Stop printing the virtual memory layout

For security reasons, don't display the kernel's virtual memory layout.

Kees Cook points out:
"These have been entirely removed on other architectures, so let's
just do the same for ia32 and remove it unconditionally."

071929dbdd86 ("arm64: Stop printing the virtual memory layout")
1c31d4e96b8c ("ARM: 8820/1: mm: Stop printing the virtual memory layout")
31833332f798 ("m68k/mm: Stop printing the virtual memory layout")
fd8d0ca25631 ("parisc: Hide virtual kernel memory layout")
adb1fe9ae2ee ("mm/page_alloc: Remove kernel address exposure in free_reserved_area()")

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Tycho Andersen <tycho@tycho.ws>
Acked-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200305150152.831697-1-nivedita@alum.mit.edu

diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 23df4885bbede4a72763e95b5dbab74bcfb1c3a5..8ae0272c1c51240fba2acaf936319058508fc217 100644 (file)
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -788,44 +788,6 @@ void __init mem_init(void)
        x86_init.hyper.init_after_bootmem();
 
        mem_init_print_info(NULL);
-       printk(KERN_INFO "virtual kernel memory layout:\n"
-               "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
-               "  cpu_entry : 0x%08lx - 0x%08lx   (%4ld kB)\n"
-#ifdef CONFIG_HIGHMEM
-               "    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
-#endif
-               "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
-               "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
-               "      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
-               "      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
-               "      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
-               FIXADDR_START, FIXADDR_TOP,
-               (FIXADDR_TOP - FIXADDR_START) >> 10,
-
-               CPU_ENTRY_AREA_BASE,
-               CPU_ENTRY_AREA_BASE + CPU_ENTRY_AREA_MAP_SIZE,
-               CPU_ENTRY_AREA_MAP_SIZE >> 10,
-
-#ifdef CONFIG_HIGHMEM
-               PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
-               (LAST_PKMAP*PAGE_SIZE) >> 10,
-#endif
-
-               VMALLOC_START, VMALLOC_END,
-               (VMALLOC_END - VMALLOC_START) >> 20,
-
-               (unsigned long)__va(0), (unsigned long)high_memory,
-               ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
-
-               (unsigned long)&__init_begin, (unsigned long)&__init_end,
-               ((unsigned long)&__init_end -
-                (unsigned long)&__init_begin) >> 10,
-
-               (unsigned long)&_etext, (unsigned long)&_edata,
-               ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
-
-               (unsigned long)&_text, (unsigned long)&_etext,
-               ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
 
        /*
         * Check boundaries twice: Some fundamental inconsistencies can