From: Zhihao Cheng chengzhihao1@huawei.com

mainline inclusion from mainline-v6.6-rc5 commit 017c73a34a661a861712f7cc1393a123e5b2208c category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I6YOAJ CVE: CVE-2023-31085

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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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@... Signed-off-by: Zhihao Cheng chengzhihao1@huawei.com Reviewed-by: Miquel Raynal miquel.raynal@bootlin.com Signed-off-by: Richard Weinberger richard@nod.at Signed-off-by: ZhaoLong Wang wangzhaolong1@huawei.com --- 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 1052bb60063f..403f61c3bf73 100644 --- a/drivers/mtd/ubi/build.c +++ b/drivers/mtd/ubi/build.c @@ -896,6 +896,13 @@ 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++)