diff options
| author | Alexander Usyskin <alexander.usyskin@intel.com> | 2023-07-31 14:58:36 +0300 |
|---|---|---|
| committer | Miquel Raynal <miquel.raynal@bootlin.com> | 2023-08-04 09:01:31 +0200 |
| commit | e9714c22c1a8238a85d069b1517941fc723312f7 (patch) | |
| tree | 17c305b0aff03f1165e18af417029205bfaa8424 /drivers/mtd/mtdcore.c | |
| parent | d2236f6219fac62ee22d971e06a04148f4eb8cca (diff) | |
mtd: fix use-after-free in mtd release
I case of partition device_unregister() in mtd_device_release()
calls mtd_release() which frees mtd_info structure for partition.
All code after device_unregister in mtd_device_release thus
uses already freed memory.
Move part of code to mtd_release() and restict mtd->dev cleanup
to non-partion object.
For partition object such cleanup have no sense as partition
mtd_info is removed.
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Fixes: 19bfa9ebebb5 ("mtd: use refcount to prevent corruption")
Reviewed-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20230731115836.542747-1-alexander.usyskin@intel.com
Diffstat (limited to 'drivers/mtd/mtdcore.c')
| -rw-r--r-- | drivers/mtd/mtdcore.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index 2466ea466466..46f15f676491 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -93,6 +93,9 @@ static void mtd_release(struct device *dev) struct mtd_info *mtd = dev_get_drvdata(dev); dev_t index = MTD_DEVT(mtd->index); + idr_remove(&mtd_idr, mtd->index); + of_node_put(mtd_get_of_node(mtd)); + if (mtd_is_partition(mtd)) release_mtd_partition(mtd); @@ -103,6 +106,7 @@ static void mtd_release(struct device *dev) static void mtd_device_release(struct kref *kref) { struct mtd_info *mtd = container_of(kref, struct mtd_info, refcnt); + bool is_partition = mtd_is_partition(mtd); debugfs_remove_recursive(mtd->dbg.dfs_dir); @@ -111,11 +115,13 @@ static void mtd_device_release(struct kref *kref) device_unregister(&mtd->dev); - /* Clear dev so mtd can be safely re-registered later if desired */ - memset(&mtd->dev, 0, sizeof(mtd->dev)); - - idr_remove(&mtd_idr, mtd->index); - of_node_put(mtd_get_of_node(mtd)); + /* + * Clear dev so mtd can be safely re-registered later if desired. + * Should not be done for partition, + * as it was already destroyed in device_unregister(). + */ + if (!is_partition) + memset(&mtd->dev, 0, sizeof(mtd->dev)); module_put(THIS_MODULE); } |