2020-08-03 01:24:07

by Arvind Sankar

Subject: [PATCH 1/1] x86/kaslr: Replace strlen with strnlen

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

Signed-off-by: Arvind Sankar <[email protected]>
---
arch/x86/boot/compressed/kaslr.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 903ccdca0551..a5842eea84cb 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -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,
--
2.26.2

2020-08-06 23:42:05

by tip-bot2 for Alexey Makhalov

Subject: [tip: x86/kaslr] x86/kaslr: Replace strlen() with strnlen()

The following commit has been merged into the x86/kaslr branch of tip:

Commit-ID: 76167e5c5457aee8fba3edc5b8554183696fc94d
Gitweb: https://git.kernel.org/tip/76167e5c5457aee8fba3edc5b8554183696fc94d
Author: Arvind Sankar <[email protected]>
AuthorDate: Sun, 02 Aug 2020 21:15:34 -04:00
Committer: Ingo Molnar <[email protected]>
CommitterDate: Thu, 06 Aug 2020 17:03:19 +02:00

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

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

Signed-off-by: Arvind Sankar <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/boot/compressed/kaslr.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 735fcb2..6d39743 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -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,