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Subject[PATCH v2 2/4] chardev: add a check for given minor range
Date
register_chrdev_region() carefully checks minor range
before calling __register_chrdev_region() but there is
another path from alloc_chrdev_region() which does not
check the range properly. So add a check for given minor
range in __register_chrdev_region().

Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
---
v1->v2:
- Split fix and cleanup patches.
- Remove printing minor range in chrdev_show().

fs/char_dev.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/fs/char_dev.c b/fs/char_dev.c
index 8a63cfa29005..6803e98414f1 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -104,6 +104,12 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor,
int ret = 0;
int i;

+ if (minorct > MINORMASK + 1 - baseminor) {
+ pr_err("CHRDEV \"%s\" minor range requested (%u-%u) is out of range of maximum range (%u-%u) for a single major\n",
+ name, baseminor, baseminor + minorct - 1, 0, MINORMASK);
+ return ERR_PTR(-EINVAL);
+ }
+
cd = kzalloc(sizeof(struct char_device_struct), GFP_KERNEL);
if (cd == NULL)
return ERR_PTR(-ENOMEM);
--
2.20.1
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