[PATCH 5.8 517/633] lightnvm: fix out-of-bounds write to array devices->info[]

Greg Kroah-Hartman
2020-10-27T16:53:08Z

From: Colin Ian King <colin.king@canonical.com>

[ Upstream commit a48faebe65b0db55a73b9220c3d919eee849bb79 ]

There is an off-by-one array check that can lead to a out-of-bounds
write to devices->info[i]. Fix this by checking by using >= rather
than > for the size check. Also replace hard-coded array size limit
with ARRAY_SIZE on the array.

Addresses-Coverity: ("Out-of-bounds write")
Fixes: cd9e9808d18f ("lightnvm: Support for Open-Channel SSDs")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/lightnvm/core.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index db38a68abb6c0..a6f4ca438bca1 100644
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -1315,8 +1315,9 @@ static long nvm_ioctl_get_devices(struct file *file, void __user *arg)
strlcpy(info->bmname, "gennvm", sizeof(info->bmname));
i++;

- if (i > 31) {
- pr_err("max 31 devices can be reported.\n");
+ if (i >= ARRAY_SIZE(devices->info)) {
+ pr_err("max %zd devices can be reported.\n",
+ ARRAY_SIZE(devices->info));
break;
}
}
--
2.25.1