linux-kernel - [PATCH v2] rave-sp: Remove VLA

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20180427223023.11849-1-ksspiers@google.com>
Date:   Fri, 27 Apr 2018 15:30:23 -0700
From:   Kyle Spiers <ksspiers@...gle.com>
To:     lee.jones@...aro.org
Cc:     linux-kernel@...r.kernel.org, keescook@...omium.org,
        Kyle Spiers <ksspiers@...gle.com>
Subject: [PATCH v2] rave-sp: Remove VLA

As part of the effort to remove VLAs from the kernel[1], this creates
constants for the checksum lengths of CCITT and 8B2C and changes
crc_calculated to be the maximum size of a checksum.

https://lkml.org/lkml/2018/3/7/621

Signed-off-by: Kyle Spiers <ksspiers@...gle.com>
---
 drivers/mfd/rave-sp.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/mfd/rave-sp.c b/drivers/mfd/rave-sp.c
index 5c858e784a89..4ce96b7137db 100644
--- a/drivers/mfd/rave-sp.c
+++ b/drivers/mfd/rave-sp.c
@@ -45,7 +45,9 @@
 #define RAVE_SP_DLE			0x10
 
 #define RAVE_SP_MAX_DATA_SIZE		64
-#define RAVE_SP_CHECKSUM_SIZE		2  /* Worst case scenario on RDU2 */
+#define RAVE_SP_CHECKSUM_8B2C		1
+#define RAVE_SP_CHECKSUM_CCITT		2
+#define RAVE_SP_CHECKSUM_SIZE		RAVE_SP_CHECKSUM_CCITT
 /*
  * We don't store STX, ETX and unescaped bytes, so Rx is only
  * DATA + CSUM
@@ -415,7 +417,12 @@ static void rave_sp_receive_frame(struct rave_sp *sp,
 	const size_t payload_length  = length - checksum_length;
 	const u8 *crc_reported       = &data[payload_length];
 	struct device *dev           = &sp->serdev->dev;
-	u8 crc_calculated[checksum_length];
+	u8 crc_calculated[RAVE_SP_CHECKSUM_SIZE];
+
+	if (unlikely(checksum_length > sizeof(crc_calculated))) {
+		dev_warn(dev, "Checksum too long, dropping\n");
+		return;
+	}
 
 	print_hex_dump(KERN_DEBUG, "rave-sp rx: ", DUMP_PREFIX_NONE,
 		       16, 1, data, length, false);
-- 
2.17.0.441.gb46fe60e1d-goog