efi/libstub: Fix harmless command line parsing bug

When we parse the 'efi=' command line parameter in the stub, we
fail to take spaces into account. Currently, the only way this
could result in unexpected behavior is when the string 'nochunk'
appears as a separate command line argument after 'efi=xxx,yyy,zzz ',
so this is harmless in practice. But let's fix it nonetheless.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170404160245.27812-12-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index 919822b7773d5df20cd6009e3f336d48dfa2e191..3290fae0b38f4b8f71c40b0da168c303c8cbbd0d 100644 (file)
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -436,14 +436,14 @@ efi_status_t efi_parse_options(char *cmdline)
         * Remember, because efi= is also used by the kernel we need to
         * skip over arguments we don't understand.
         */
-       while (*str) {
+       while (*str && *str != ' ') {
                if (!strncmp(str, "nochunk", 7)) {
                        str += strlen("nochunk");
                        __chunk_size = -1UL;
                }
 
                /* Group words together, delimited by "," */
-               while (*str && *str != ',')
+               while (*str && *str != ' ' && *str != ',')
                        str++;
 
                if (*str == ',')