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authorLinus Torvalds <torvalds@linux-foundation.org>2014-05-21 18:59:25 +0900
committerLinus Torvalds <torvalds@linux-foundation.org>2014-05-21 18:59:25 +0900
commit439c6109922c8faa920c9b8680d63937189d6915 (patch)
tree686ad57dd77b9a462044e218b411ad9cdad63fb9
parent957cf2582adf2a2164bbbd87036138221c5c118a (diff)
parentf5c16f29bf5e57ba4051fc7785ba7f035f798c71 (diff)
downloadlinux-439c6109922c8faa920c9b8680d63937189d6915.tar.gz
Merge tag 'driver-core-3.15-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core fixes from Greg KH: "Here are two driver core (well, sysfs) fixes for 3.15-rc6 that resolve some reported issues and a regression from 3.13" * tag 'driver-core-3.15-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: sysfs: make sure read buffer is zeroed kernfs, sysfs, cgroup: restrict extra perm check on open to sysfs
-rw-r--r--fs/kernfs/file.c17
-rw-r--r--fs/sysfs/file.c3
-rw-r--r--fs/sysfs/mount.c3
-rw-r--r--include/linux/kernfs.h19
4 files changed, 32 insertions, 10 deletions
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index e01ea4a14a01..5e9a80cfc3d8 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -610,6 +610,7 @@ static void kernfs_put_open_node(struct kernfs_node *kn,
static int kernfs_fop_open(struct inode *inode, struct file *file)
{
struct kernfs_node *kn = file->f_path.dentry->d_fsdata;
+ struct kernfs_root *root = kernfs_root(kn);
const struct kernfs_ops *ops;
struct kernfs_open_file *of;
bool has_read, has_write, has_mmap;
@@ -624,14 +625,16 @@ static int kernfs_fop_open(struct inode *inode, struct file *file)
has_write = ops->write || ops->mmap;
has_mmap = ops->mmap;
- /* check perms and supported operations */
- if ((file->f_mode & FMODE_WRITE) &&
- (!(inode->i_mode & S_IWUGO) || !has_write))
- goto err_out;
+ /* see the flag definition for details */
+ if (root->flags & KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK) {
+ if ((file->f_mode & FMODE_WRITE) &&
+ (!(inode->i_mode & S_IWUGO) || !has_write))
+ goto err_out;
- if ((file->f_mode & FMODE_READ) &&
- (!(inode->i_mode & S_IRUGO) || !has_read))
- goto err_out;
+ if ((file->f_mode & FMODE_READ) &&
+ (!(inode->i_mode & S_IRUGO) || !has_read))
+ goto err_out;
+ }
/* allocate a kernfs_open_file for the file */
error = -ENOMEM;
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 28cc1acd5439..e9ef59b3abb1 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -47,12 +47,13 @@ static int sysfs_kf_seq_show(struct seq_file *sf, void *v)
ssize_t count;
char *buf;
- /* acquire buffer and ensure that it's >= PAGE_SIZE */
+ /* acquire buffer and ensure that it's >= PAGE_SIZE and clear */
count = seq_get_buf(sf, &buf);
if (count < PAGE_SIZE) {
seq_commit(sf, -1);
return 0;
}
+ memset(buf, 0, PAGE_SIZE);
/*
* Invoke show(). Control may reach here via seq file lseek even
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index a66ad6196f59..8794423f7efb 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -63,7 +63,8 @@ int __init sysfs_init(void)
{
int err;
- sysfs_root = kernfs_create_root(NULL, 0, NULL);
+ sysfs_root = kernfs_create_root(NULL, KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK,
+ NULL);
if (IS_ERR(sysfs_root))
return PTR_ERR(sysfs_root);
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index b0122dc6f96a..ca1be5c9136c 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -50,7 +50,24 @@ enum kernfs_node_flag {
/* @flags for kernfs_create_root() */
enum kernfs_root_flag {
- KERNFS_ROOT_CREATE_DEACTIVATED = 0x0001,
+ /*
+ * kernfs_nodes are created in the deactivated state and invisible.
+ * They require explicit kernfs_activate() to become visible. This
+ * can be used to make related nodes become visible atomically
+ * after all nodes are created successfully.
+ */
+ KERNFS_ROOT_CREATE_DEACTIVATED = 0x0001,
+
+ /*
+ * For regular flies, if the opener has CAP_DAC_OVERRIDE, open(2)
+ * succeeds regardless of the RW permissions. sysfs had an extra
+ * layer of enforcement where open(2) fails with -EACCES regardless
+ * of CAP_DAC_OVERRIDE if the permission doesn't have the
+ * respective read or write access at all (none of S_IRUGO or
+ * S_IWUGO) or the respective operation isn't implemented. The
+ * following flag enables that behavior.
+ */
+ KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK = 0x0002,
};
/* type-specific structures for kernfs_node union members */