From 017c73a34a661a861712f7cc1393a123e5b2208c Mon Sep 17 00:00:00 2001
From: Zhihao Cheng <chengzhihao1@huawei.com>
Date: Sun, 23 Apr 2023 19:10:41 +0800
Subject: [PATCH] ubi: Refuse attaching if mtd's erasesize is 0
Git-commit: 017c73a34a661a861712f7cc1393a123e5b2208c
Patch-mainline: v6.6-rc5
References: CVE-2023-31085 bsc#1210778
There exists mtd devices with zero erasesize, which will trigger a
divide-by-zero exception while attaching ubi device.
Fix it by refusing attaching if mtd's erasesize is 0.
Fixes: 801c135ce73d ("UBI: Unsorted Block Images")
Reported-by: Yu Hao <yhao016@ucr.edu>
Link: https://lore.kernel.org/lkml/977347543.226888.1682011999468.JavaMail.zimbra@nod.at/T/
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/mtd/ubi/build.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 8b91a55ec0d2..8ee51e49fced 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -894,6 +894,13 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
return -EINVAL;
}
+ /* UBI cannot work on flashes with zero erasesize. */
+ if (!mtd->erasesize) {
+ pr_err("ubi: refuse attaching mtd%d - zero erasesize flash is not supported\n",
+ mtd->index);
+ return -EINVAL;
+ }
+
if (ubi_num == UBI_DEV_NUM_AUTO) {
/* Search for an empty slot in the @ubi_devices array */
for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)
--
2.35.3