| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 83/85] Revert "kernel/reboot.c: convert simple_strtoul to kstrtoint" | Date | Tue, 17 Nov 2020 14:05:52 +0100 |
| |
From: Matteo Croce <mcroce@microsoft.com>
commit 8b92c4ff4423aa9900cf838d3294fcade4dbda35 upstream.
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.
Fixes: 616feab75397 ("kernel/reboot.c: convert simple_strtoul to kstrtoint") Signed-off-by: Matteo Croce <mcroce@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Petr Mladek <pmladek@suse.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Mike Rapoport <rppt@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Robin Holt <robinmholt@gmail.com> Cc: Fabian Frederick <fabf@skynet.be> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20201103214025.116799-2-mcroce@linux.microsoft.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [sudip: use reboot_mode instead of mode] Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- kernel/reboot.c | 21 +++++++-------------- 1 file changed, 7 insertions(+), 14 deletions(-)
--- a/kernel/reboot.c +++ b/kernel/reboot.c @@ -512,22 +512,15 @@ 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 reboot_mode = REBOOT_SOFT; break; - } + case 'g': reboot_mode = REBOOT_GPIO; break;
|