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

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Date:   Wed, 5 Apr 2017 01:56:13 -0700
From:   tip-bot for Ard Biesheuvel <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     hpa@...or.com, matt@...eblueprint.co.uk, tglx@...utronix.de,
        mingo@...nel.org, linux-kernel@...r.kernel.org,
        ard.biesheuvel@...aro.org, torvalds@...ux-foundation.org,
        peterz@...radead.org
Subject: [tip:efi/core] efi/libstub: Fix harmless command line parsing bug

Commit-ID:  935061e3a7de5eae398327de9f7b92588bfcf7fc
Gitweb:     http://git.kernel.org/tip/935061e3a7de5eae398327de9f7b92588bfcf7fc
Author:     Ard Biesheuvel <ard.biesheuvel@...aro.org>
AuthorDate: Tue, 4 Apr 2017 17:02:45 +0100
Committer:  Ingo Molnar <mingo@...nel.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@...aro.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Matt Fleming <matt@...eblueprint.co.uk>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-efi@...r.kernel.org
Link: http://lkml.kernel.org/r/20170404160245.27812-12-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@...nel.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 == ',')