From: Matteo Croce <mcroce@xxxxxxxxxxxxx>
Subject: Revert "kernel/reboot.c: convert simple_strtoul to kstrtoint"
Patch series "fix parsing of reboot= cmdline", v3.
The parsing of the reboot= cmdline has two major errors:
- a missing bound check can crash the system on reboot
- parsing of the cpu number only works if specified last
Fix both.
This patch (of 2):
This reverts commit 616feab753972b97.
kstrtoint() and simple_strtoul() have a subtle difference which makes them
non interchangeable: if a non digit character is found amid the parsing,
the former will return an error, while the latter will just stop parsing,
e.g. simple_strtoul("123xyx") = 123.
The kernel cmdline reboot= argument allows to specify the CPU used for
rebooting, with the syntax `s####` among the other flags, e.g.
"reboot=warm,s31,force", so if this flag is not the last given, it's
silently ignored as well as the subsequent ones.
Link: https://lkml.kernel.org/r/20201103214025.116799-2-mcroce@xxxxxxxxxxxxxxxxxxx
Fixes: 616feab75397 ("kernel/reboot.c: convert simple_strtoul to kstrtoint")
Signed-off-by: Matteo Croce <mcroce@xxxxxxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Cc: Petr Mladek <pmladek@xxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Robin Holt <robinmholt@xxxxxxxxx>
Cc: Fabian Frederick <fabf@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/reboot.c | 21 +++++++--------------
1 file changed, 7 insertions(+), 14 deletions(-)
--- a/kernel/reboot.c~revert-kernel-rebootc-convert-simple_strtoul-to-kstrtoint
+++ a/kernel/reboot.c
@@ -551,22 +551,15 @@ static int __init reboot_setup(char *str
break;
case 's':
- {
- int rc;
-
- if (isdigit(*(str+1))) {
- rc = kstrtoint(str+1, 0, &reboot_cpu);
- if (rc)
- return rc;
- } else if (str[1] == 'm' && str[2] == 'p' &&
- isdigit(*(str+3))) {
- rc = kstrtoint(str+3, 0, &reboot_cpu);
- if (rc)
- return rc;
- } else
+ if (isdigit(*(str+1)))
+ reboot_cpu = simple_strtoul(str+1, NULL, 0);
+ else if (str[1] == 'm' && str[2] == 'p' &&
+ isdigit(*(str+3)))
+ reboot_cpu = simple_strtoul(str+3, NULL, 0);
+ else
*mode = REBOOT_SOFT;
break;
- }
+
case 'g':
*mode = REBOOT_GPIO;
break;
_
