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authorEric W. Biederman <ebiederm@xmission.com>2016-06-09 15:34:02 -0500
committerEric W. Biederman <ebiederm@xmission.com>2016-06-23 15:41:57 -0500
commita2982cc922c3068783eb9a1f77a5626a1ec36a1f (patch)
tree61ccc6ad01f8804d5290ae4565ba8d4238bf648a /fs/namei.c
parent3ee690143c3c99f6c0e83f08ff17556890bc6027 (diff)
vfs: Generalize filesystem nodev handling.
Introduce a function may_open_dev that tests MNT_NODEV and a new superblock flab SB_I_NODEV. Use this new function in all of the places where MNT_NODEV was previously tested. Add the new SB_I_NODEV s_iflag to proc, sysfs, and mqueuefs as those filesystems should never support device nodes, and a simple superblock flags makes that very hard to get wrong. With SB_I_NODEV set if any device nodes somehow manage to show up on on a filesystem those device nodes will be unopenable. Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/fs/namei.c b/fs/namei.c
index 6a82fb7e2127..757a32725d92 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2881,6 +2881,12 @@ int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
}
EXPORT_SYMBOL(vfs_create);
+bool may_open_dev(const struct path *path)
+{
+ return !(path->mnt->mnt_flags & MNT_NODEV) &&
+ !(path->mnt->mnt_sb->s_iflags & SB_I_NODEV);
+}
+
static int may_open(struct path *path, int acc_mode, int flag)
{
struct dentry *dentry = path->dentry;
@@ -2899,7 +2905,7 @@ static int may_open(struct path *path, int acc_mode, int flag)
break;
case S_IFBLK:
case S_IFCHR:
- if (path->mnt->mnt_flags & MNT_NODEV)
+ if (!may_open_dev(path))
return -EACCES;
/*FALLTHRU*/
case S_IFIFO: