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x86/kaslr: Replace strlen() with strnlen()

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strnlen is safer in case the command line is not NUL-terminated.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200803011534.730645-2-nivedita@alum.mit.edu
This commit is contained in:
Arvind Sankar 2020-08-02 21:15:34 -04:00 committed by Ingo Molnar
parent f49236ae42
commit 76167e5c54
1 changed files with 6 additions and 2 deletions
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8
arch/x86/boot/compressed/kaslr.c
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@ -43,6 +43,10 @@
#define STATIC
#include <linux/decompress/mm.h>
#define _SETUP
#include <asm/setup.h> /* For COMMAND_LINE_SIZE */
#undef _SETUP
#ifdef CONFIG_X86_5LEVEL
unsigned int __pgtable_l5_enabled;
unsigned int pgdir_shift __ro_after_init = 39;
@ -278,7 +282,7 @@ static void handle_mem_options(void)
if (!args)
return;
len = strlen(args);
len = strnlen(args, COMMAND_LINE_SIZE-1);
tmp_cmdline = malloc(len + 1);
if (!tmp_cmdline)
error("Failed to allocate space for tmp_cmdline");
@ -425,7 +429,7 @@ static void mem_avoid_init(unsigned long input, unsigned long input_size,
cmd_line = get_cmd_line_ptr();
/* Calculate size of cmd_line. */
if (cmd_line) {
cmd_line_size = strlen((char *)cmd_line) + 1;
cmd_line_size = strnlen((char *)cmd_line, COMMAND_LINE_SIZE-1) + 1;
mem_avoid[MEM_AVOID_CMDLINE].start = cmd_line;
mem_avoid[MEM_AVOID_CMDLINE].size = cmd_line_size;
add_identity_map(mem_avoid[MEM_AVOID_CMDLINE].start,