autofs4: check dev ioctl size before allocating

PATCH New Ian Kent 1 participant 1 message Apr 7, 2014 Kernel automounter

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Ian Kent

author maintainer

2014-04-07 01:42 UTC #0 lore raw

PATCH 1/1 autofs4: check dev ioctl size before allocating

From: Sasha Levin <[email protected]>

There wasn't any check of the size passed from userspace before trying to allocate the memory required.

This meant that userspace might request more space than allowed, triggering an OOM.

Signed-off-by Sasha Levin <[email protected]>

Signed-off-by Ian Kent <[email protected]>

---
 fs/autofs4/dev-ioctl.c |    3 +++
 1 file changed, 3 insertions(+)

fs/autofs4/dev-ioctl.c +3 -0

index 3182c0e..232e03d 100644
@@ -103,6 +103,9 @@ static struct autofs_dev_ioctl *copy_dev_ioctl(struct autofs_dev_ioctl __user *i
 	if (tmp.size < sizeof(tmp))
 		return ERR_PTR(-EINVAL);
 
+	if (tmp.size > (PATH_MAX + sizeof(tmp)))
+		return ERR_PTR(-ENAMETOOLONG);
+
 	return memdup_user(in, tmp.size);
 }