[tip:efi/core] efi/libstub: Fix harmless command line parsing bug

tip-bot for Ard Biesheuvel
2017-04-05T09:01:46Z

Commit-ID: 935061e3a7de5eae398327de9f7b92588bfcf7fc
Gitweb: http://git.kernel.org/tip/935061e3a7de5eae398327de9f7b92588bfcf7fc
Author: Ard Biesheuvel <ard.biesheuvel@linaro.org>
AuthorDate: Tue, 4 Apr 2017 17:02:45 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 5 Apr 2017 09:27:53 +0200

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>
---
drivers/firmware/efi/libstub/efi-stub-helper.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index 919822b..3290fae 100644
--- 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 == ',')