devpts: if initialization failed, don't crash when opening /dev/ptmx
If devpts failed to initialize, it would store an ERR_PTR in the global devpts_mnt. A subsequent open of /dev/ptmx would call devpts_new_index, which would dereference devpts_mnt and crash. Avoid storing invalid values in devpts_mnt; leave it NULL instead. Make both devpts_new_index and devpts_pty_new fail gracefully with ENODEV in that case, which then becomes the return value to the userspace open call on /dev/ptmx. [akpm@linux-foundation.org: remove unneeded static] Signed-off-by: Josh Triplett <josh@joshtriplett.org> Reported-by: Fengguang Wu <fengguang.wu@intel.com> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
15f1d82781
commit
9ce71148b0
|
@ -142,6 +142,8 @@ static inline struct super_block *pts_sb_from_inode(struct inode *inode)
|
||||||
if (inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC)
|
if (inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC)
|
||||||
return inode->i_sb;
|
return inode->i_sb;
|
||||||
#endif
|
#endif
|
||||||
|
if (!devpts_mnt)
|
||||||
|
return NULL;
|
||||||
return devpts_mnt->mnt_sb;
|
return devpts_mnt->mnt_sb;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -525,10 +527,14 @@ static struct file_system_type devpts_fs_type = {
|
||||||
int devpts_new_index(struct inode *ptmx_inode)
|
int devpts_new_index(struct inode *ptmx_inode)
|
||||||
{
|
{
|
||||||
struct super_block *sb = pts_sb_from_inode(ptmx_inode);
|
struct super_block *sb = pts_sb_from_inode(ptmx_inode);
|
||||||
struct pts_fs_info *fsi = DEVPTS_SB(sb);
|
struct pts_fs_info *fsi;
|
||||||
int index;
|
int index;
|
||||||
int ida_ret;
|
int ida_ret;
|
||||||
|
|
||||||
|
if (!sb)
|
||||||
|
return -ENODEV;
|
||||||
|
|
||||||
|
fsi = DEVPTS_SB(sb);
|
||||||
retry:
|
retry:
|
||||||
if (!ida_pre_get(&fsi->allocated_ptys, GFP_KERNEL))
|
if (!ida_pre_get(&fsi->allocated_ptys, GFP_KERNEL))
|
||||||
return -ENOMEM;
|
return -ENOMEM;
|
||||||
|
@ -584,11 +590,18 @@ struct inode *devpts_pty_new(struct inode *ptmx_inode, dev_t device, int index,
|
||||||
struct dentry *dentry;
|
struct dentry *dentry;
|
||||||
struct super_block *sb = pts_sb_from_inode(ptmx_inode);
|
struct super_block *sb = pts_sb_from_inode(ptmx_inode);
|
||||||
struct inode *inode;
|
struct inode *inode;
|
||||||
struct dentry *root = sb->s_root;
|
struct dentry *root;
|
||||||
struct pts_fs_info *fsi = DEVPTS_SB(sb);
|
struct pts_fs_info *fsi;
|
||||||
struct pts_mount_opts *opts = &fsi->mount_opts;
|
struct pts_mount_opts *opts;
|
||||||
char s[12];
|
char s[12];
|
||||||
|
|
||||||
|
if (!sb)
|
||||||
|
return ERR_PTR(-ENODEV);
|
||||||
|
|
||||||
|
root = sb->s_root;
|
||||||
|
fsi = DEVPTS_SB(sb);
|
||||||
|
opts = &fsi->mount_opts;
|
||||||
|
|
||||||
inode = new_inode(sb);
|
inode = new_inode(sb);
|
||||||
if (!inode)
|
if (!inode)
|
||||||
return ERR_PTR(-ENOMEM);
|
return ERR_PTR(-ENOMEM);
|
||||||
|
@ -676,12 +689,16 @@ static int __init init_devpts_fs(void)
|
||||||
struct ctl_table_header *table;
|
struct ctl_table_header *table;
|
||||||
|
|
||||||
if (!err) {
|
if (!err) {
|
||||||
|
struct vfsmount *mnt;
|
||||||
|
|
||||||
table = register_sysctl_table(pty_root_table);
|
table = register_sysctl_table(pty_root_table);
|
||||||
devpts_mnt = kern_mount(&devpts_fs_type);
|
mnt = kern_mount(&devpts_fs_type);
|
||||||
if (IS_ERR(devpts_mnt)) {
|
if (IS_ERR(mnt)) {
|
||||||
err = PTR_ERR(devpts_mnt);
|
err = PTR_ERR(mnt);
|
||||||
unregister_filesystem(&devpts_fs_type);
|
unregister_filesystem(&devpts_fs_type);
|
||||||
unregister_sysctl_table(table);
|
unregister_sysctl_table(table);
|
||||||
|
} else {
|
||||||
|
devpts_mnt = mnt;
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
return err;
|
return err;
|
||||||
|
|
Loading…
Reference in New Issue