| From: Dave Hansen <dave.hansen@linux.intel.com> |
| Date: Tue, 22 Dec 2015 14:52:41 -0800 |
| Subject: x86/boot: Simplify early command line parsing |
| |
| commit 4de07ea481361b08fe13735004dafae862482d38 upstream. |
| |
| __cmdline_find_option_bool() tries to account for both NULL-terminated |
| and non-NULL-terminated strings. It keeps 'pos' to look for the end of |
| the buffer and also looks for '!c' in a bunch of places to look for NULL |
| termination. |
| |
| But, it also calls strlen(). You can't call strlen on a |
| non-NULL-terminated string. |
| |
| If !strlen(cmdline), then cmdline[0]=='\0'. In that case, we will go in |
| to the while() loop, set c='\0', hit st_wordstart, notice !c, and will |
| immediately return 0. |
| |
| So, remove the strlen(). It is unnecessary and unsafe. |
| |
| Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> |
| Signed-off-by: Borislav Petkov <bp@suse.de> |
| Cc: Andy Lutomirski <luto@amacapital.net> |
| Cc: Borislav Petkov <bp@alien8.de> |
| Cc: Brian Gerst <brgerst@gmail.com> |
| Cc: Denys Vlasenko <dvlasenk@redhat.com> |
| Cc: H. Peter Anvin <hpa@zytor.com> |
| Cc: Linus Torvalds <torvalds@linux-foundation.org> |
| Cc: Peter Zijlstra <peterz@infradead.org> |
| Cc: Thomas Gleixner <tglx@linutronix.de> |
| Cc: fenghua.yu@intel.com |
| Cc: yu-cheng.yu@intel.com |
| Link: http://lkml.kernel.org/r/20151222225241.15365E43@viggo.jf.intel.com |
| Signed-off-by: Ingo Molnar <mingo@kernel.org> |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| arch/x86/lib/cmdline.c | 3 --- |
| 1 file changed, 3 deletions(-) |
| |
| diff --git a/arch/x86/lib/cmdline.c b/arch/x86/lib/cmdline.c |
| index ff8d1beead6c..945a639c02dd 100644 |
| --- a/arch/x86/lib/cmdline.c |
| +++ b/arch/x86/lib/cmdline.c |
| @@ -39,9 +39,6 @@ int cmdline_find_option_bool(const char *cmdline, const char *option) |
| if (!cmdline) |
| return -1; /* No command line */ |
| |
| - if (!strlen(cmdline)) |
| - return 0; |
| - |
| /* |
| * This 'pos' check ensures we do not overrun |
| * a non-NULL-terminated 'cmdline' |
| |