From b26adf880eba03ac6f2b1dd87426bb96fd2a0282 Mon Sep 17 00:00:00 2001 From: Scotty Bauer Date: Tue, 1 Dec 2015 10:52:46 -0700 Subject: [PATCH] dm ioctl: Access user-land memory through safe functions. This patch fixes a user-land dereference. Now we use the safe copy_from_user to access the memory. Signed-off-by: Scotty Bauer --- drivers/md/dm-ioctl.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 80a4395..39a9d1a 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -1642,9 +1642,13 @@ static ioctl_fn lookup_ioctl(unsigned int cmd, int *ioctl_flags) static int check_version(unsigned int cmd, struct dm_ioctl __user *user) { uint32_t version[3]; + uint32_t __user *version_ptr; int r = 0; - if (copy_from_user(version, user->version, sizeof(version))) + if (copy_from_user(&version_ptr, &user->version, sizeof(version_ptr))) + return -EFAULT; + + if (copy_from_user(version, version_ptr, sizeof(version))) return -EFAULT; if ((DM_VERSION_MAJOR != version[0]) || @@ -1663,7 +1667,7 @@ static int check_version(unsigned int cmd, struct dm_ioctl __user *user) version[0] = DM_VERSION_MAJOR; version[1] = DM_VERSION_MINOR; version[2] = DM_VERSION_PATCHLEVEL; - if (copy_to_user(user->version, version, sizeof(version))) + if (copy_to_user(version_ptr, version, sizeof(version))) return -EFAULT; return r; -- 1.9.1