linux-kernel - [PATCH] xtensa/mm: Stop printing the virtual memory layout

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Message-Id: <20200305151144.836824-1-nivedita@alum.mit.edu>
Date:   Thu,  5 Mar 2020 10:11:44 -0500
From:   Arvind Sankar <nivedita@...m.mit.edu>
To:     Kees Cook <keescook@...omium.org>
Cc:     "Tobin C . Harding" <me@...in.cc>, Tycho Andersen <tycho@...ho.ws>,
        kernel-hardening@...ts.openwall.com,
        Chris Zankel <chris@...kel.net>,
        Max Filippov <jcmvbkbc@...il.com>,
        linux-xtensa@...ux-xtensa.org, linux-kernel@...r.kernel.org
Subject: [PATCH] xtensa/mm: Stop printing the virtual memory layout

For security, 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@...m.mit.edu>
---
 arch/xtensa/mm/init.c | 46 -------------------------------------------
 1 file changed, 46 deletions(-)

diff --git a/arch/xtensa/mm/init.c b/arch/xtensa/mm/init.c
index 19c625e6d81f..7ba3f1fce8ec 100644
--- a/arch/xtensa/mm/init.c
+++ b/arch/xtensa/mm/init.c
@@ -155,52 +155,6 @@ void __init mem_init(void)
 	memblock_free_all();
 
 	mem_init_print_info(NULL);
-	pr_info("virtual kernel memory layout:\n"
-#ifdef CONFIG_KASAN
-		"    kasan   : 0x%08lx - 0x%08lx  (%5lu MB)\n"
-#endif
-#ifdef CONFIG_MMU
-		"    vmalloc : 0x%08lx - 0x%08lx  (%5lu MB)\n"
-#endif
-#ifdef CONFIG_HIGHMEM
-		"    pkmap   : 0x%08lx - 0x%08lx  (%5lu kB)\n"
-		"    fixmap  : 0x%08lx - 0x%08lx  (%5lu kB)\n"
-#endif
-		"    lowmem  : 0x%08lx - 0x%08lx  (%5lu MB)\n"
-		"    .text   : 0x%08lx - 0x%08lx  (%5lu kB)\n"
-		"    .rodata : 0x%08lx - 0x%08lx  (%5lu kB)\n"
-		"    .data   : 0x%08lx - 0x%08lx  (%5lu kB)\n"
-		"    .init   : 0x%08lx - 0x%08lx  (%5lu kB)\n"
-		"    .bss    : 0x%08lx - 0x%08lx  (%5lu kB)\n",
-#ifdef CONFIG_KASAN
-		KASAN_SHADOW_START, KASAN_SHADOW_START + KASAN_SHADOW_SIZE,
-		KASAN_SHADOW_SIZE >> 20,
-#endif
-#ifdef CONFIG_MMU
-		VMALLOC_START, VMALLOC_END,
-		(VMALLOC_END - VMALLOC_START) >> 20,
-#ifdef CONFIG_HIGHMEM
-		PKMAP_BASE, PKMAP_BASE + LAST_PKMAP * PAGE_SIZE,
-		(LAST_PKMAP*PAGE_SIZE) >> 10,
-		FIXADDR_START, FIXADDR_TOP,
-		(FIXADDR_TOP - FIXADDR_START) >> 10,
-#endif
-		PAGE_OFFSET, PAGE_OFFSET +
-		(max_low_pfn - min_low_pfn) * PAGE_SIZE,
-#else
-		min_low_pfn * PAGE_SIZE, max_low_pfn * PAGE_SIZE,
-#endif
-		((max_low_pfn - min_low_pfn) * PAGE_SIZE) >> 20,
-		(unsigned long)_text, (unsigned long)_etext,
-		(unsigned long)(_etext - _text) >> 10,
-		(unsigned long)__start_rodata, (unsigned long)__end_rodata,
-		(unsigned long)(__end_rodata - __start_rodata) >> 10,
-		(unsigned long)_sdata, (unsigned long)_edata,
-		(unsigned long)(_edata - _sdata) >> 10,
-		(unsigned long)__init_begin, (unsigned long)__init_end,
-		(unsigned long)(__init_end - __init_begin) >> 10,
-		(unsigned long)__bss_start, (unsigned long)__bss_stop,
-		(unsigned long)(__bss_stop - __bss_start) >> 10);
 }
 
 static void __init parse_memmap_one(char *p)
-- 
2.24.1