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Subject[PATCH 4.9 125/157] fuse: fix bad inode
Date
From: Miklos Szeredi <mszeredi@redhat.com>

commit 5d069dbe8aaf2a197142558b6fb2978189ba3454 upstream.

Jan Kara's analysis of the syzbot report (edited):

The reproducer opens a directory on FUSE filesystem, it then attaches
dnotify mark to the open directory. After that a fuse_do_getattr() call
finds that attributes returned by the server are inconsistent, and calls
make_bad_inode() which, among other things does:

inode->i_mode = S_IFREG;

This then confuses dnotify which doesn't tear down its structures
properly and eventually crashes.

Avoid calling make_bad_inode() on a live inode: switch to a private flag on
the fuse inode. Also add the test to ops which the bad_inode_ops would
have caught.

This bug goes back to the initial merge of fuse in 2.6.14...

Reported-by: syzbot+f427adf9324b92652ccc@syzkaller.appspotmail.com
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Tested-by: Jan Kara <jack@suse.cz>
Cc: <stable@vger.kernel.org>
[bwh: Backported to 4.9:
- Drop changes in fuse_dir_fsync(), fuse_readahead(), fuse_evict_inode()
- In fuse_get_link(), return ERR_PTR(-EIO) for bad inodes
- Convert some additional calls to is_bad_inode()
- Adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/fuse/acl.c | 6 ++++++
fs/fuse/dir.c | 40 +++++++++++++++++++++++++++++++++++-----
fs/fuse/file.c | 27 ++++++++++++++++++---------
fs/fuse/fuse_i.h | 12 ++++++++++++
fs/fuse/inode.c | 2 +-
fs/fuse/xattr.c | 9 +++++++++
6 files changed, 81 insertions(+), 15 deletions(-)

--- a/fs/fuse/acl.c
+++ b/fs/fuse/acl.c
@@ -19,6 +19,9 @@ struct posix_acl *fuse_get_acl(struct in
void *value = NULL;
struct posix_acl *acl;

+ if (fuse_is_bad(inode))
+ return ERR_PTR(-EIO);
+
if (!fc->posix_acl || fc->no_getxattr)
return NULL;

@@ -53,6 +56,9 @@ int fuse_set_acl(struct inode *inode, st
const char *name;
int ret;

+ if (fuse_is_bad(inode))
+ return -EIO;
+
if (!fc->posix_acl || fc->no_setxattr)
return -EOPNOTSUPP;

--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -187,7 +187,7 @@ static int fuse_dentry_revalidate(struct
int ret;

inode = d_inode_rcu(entry);
- if (inode && is_bad_inode(inode))
+ if (inode && fuse_is_bad(inode))
goto invalid;
else if (time_before64(fuse_dentry_time(entry), get_jiffies_64()) ||
(flags & LOOKUP_REVAL)) {
@@ -364,6 +364,9 @@ static struct dentry *fuse_lookup(struct
bool outarg_valid = true;
bool locked;

+ if (fuse_is_bad(dir))
+ return ERR_PTR(-EIO);
+
locked = fuse_lock_inode(dir);
err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name,
&outarg, &inode);
@@ -504,6 +507,9 @@ static int fuse_atomic_open(struct inode
struct fuse_conn *fc = get_fuse_conn(dir);
struct dentry *res = NULL;

+ if (fuse_is_bad(dir))
+ return -EIO;
+
if (d_in_lookup(entry)) {
res = fuse_lookup(dir, entry, 0);
if (IS_ERR(res))
@@ -551,6 +557,9 @@ static int create_new_entry(struct fuse_
int err;
struct fuse_forget_link *forget;

+ if (fuse_is_bad(dir))
+ return -EIO;
+
forget = fuse_alloc_forget();
if (!forget)
return -ENOMEM;
@@ -672,6 +681,9 @@ static int fuse_unlink(struct inode *dir
struct fuse_conn *fc = get_fuse_conn(dir);
FUSE_ARGS(args);

+ if (fuse_is_bad(dir))
+ return -EIO;
+
args.in.h.opcode = FUSE_UNLINK;
args.in.h.nodeid = get_node_id(dir);
args.in.numargs = 1;
@@ -708,6 +720,9 @@ static int fuse_rmdir(struct inode *dir,
struct fuse_conn *fc = get_fuse_conn(dir);
FUSE_ARGS(args);

+ if (fuse_is_bad(dir))
+ return -EIO;
+
args.in.h.opcode = FUSE_RMDIR;
args.in.h.nodeid = get_node_id(dir);
args.in.numargs = 1;
@@ -786,6 +801,9 @@ static int fuse_rename2(struct inode *ol
struct fuse_conn *fc = get_fuse_conn(olddir);
int err;

+ if (fuse_is_bad(olddir))
+ return -EIO;
+
if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
return -EINVAL;

@@ -921,7 +939,7 @@ static int fuse_do_getattr(struct inode
if (!err) {
if (fuse_invalid_attr(&outarg.attr) ||
(inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
- make_bad_inode(inode);
+ fuse_make_bad(inode);
err = -EIO;
} else {
fuse_change_attributes(inode, &outarg.attr,
@@ -1114,6 +1132,9 @@ static int fuse_permission(struct inode
bool refreshed = false;
int err = 0;

+ if (fuse_is_bad(inode))
+ return -EIO;
+
if (!fuse_allow_current_process(fc))
return -EACCES;

@@ -1251,7 +1272,7 @@ retry:
dput(dentry);
goto retry;
}
- if (is_bad_inode(inode)) {
+ if (fuse_is_bad(inode)) {
dput(dentry);
return -EIO;
}
@@ -1349,7 +1370,7 @@ static int fuse_readdir(struct file *fil
u64 attr_version = 0;
bool locked;

- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
return -EIO;

req = fuse_get_req(fc, 1);
@@ -1409,6 +1430,9 @@ static const char *fuse_get_link(struct
if (!dentry)
return ERR_PTR(-ECHILD);

+ if (fuse_is_bad(inode))
+ return ERR_PTR(-EIO);
+
link = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!link)
return ERR_PTR(-ENOMEM);
@@ -1707,7 +1731,7 @@ int fuse_do_setattr(struct dentry *dentr

if (fuse_invalid_attr(&outarg.attr) ||
(inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
- make_bad_inode(inode);
+ fuse_make_bad(inode);
err = -EIO;
goto error;
}
@@ -1763,6 +1787,9 @@ static int fuse_setattr(struct dentry *e
struct file *file = (attr->ia_valid & ATTR_FILE) ? attr->ia_file : NULL;
int ret;

+ if (fuse_is_bad(inode))
+ return -EIO;
+
if (!fuse_allow_current_process(get_fuse_conn(inode)))
return -EACCES;

@@ -1821,6 +1848,9 @@ static int fuse_getattr(struct vfsmount
struct inode *inode = d_inode(entry);
struct fuse_conn *fc = get_fuse_conn(inode);

+ if (fuse_is_bad(inode))
+ return -EIO;
+
if (!fuse_allow_current_process(fc))
return -EACCES;

--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -206,6 +206,9 @@ int fuse_open_common(struct inode *inode
fc->atomic_o_trunc &&
fc->writeback_cache;

+ if (fuse_is_bad(inode))
+ return -EIO;
+
err = generic_file_open(inode, file);
if (err)
return err;
@@ -411,7 +414,7 @@ static int fuse_flush(struct file *file,
struct fuse_flush_in inarg;
int err;

- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
return -EIO;

if (fc->no_flush)
@@ -459,7 +462,7 @@ int fuse_fsync_common(struct file *file,
struct fuse_fsync_in inarg;
int err;

- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
return -EIO;

inode_lock(inode);
@@ -771,7 +774,7 @@ static int fuse_readpage(struct file *fi
int err;

err = -EIO;
- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
goto out;

err = fuse_do_readpage(file, page);
@@ -898,7 +901,7 @@ static int fuse_readpages(struct file *f
int nr_alloc = min_t(unsigned, nr_pages, FUSE_MAX_PAGES_PER_REQ);

err = -EIO;
- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
goto out;

data.file = file;
@@ -928,6 +931,9 @@ static ssize_t fuse_file_read_iter(struc
struct inode *inode = iocb->ki_filp->f_mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);

+ if (fuse_is_bad(inode))
+ return -EIO;
+
/*
* In auto invalidate mode, always update attributes on read.
* Otherwise, only update if we attempt to read past EOF (to ensure
@@ -1123,7 +1129,7 @@ static ssize_t fuse_perform_write(struct
int err = 0;
ssize_t res = 0;

- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
return -EIO;

if (inode->i_size < pos + iov_iter_count(ii))
@@ -1180,6 +1186,9 @@ static ssize_t fuse_file_write_iter(stru
ssize_t err;
loff_t endbyte = 0;

+ if (fuse_is_bad(inode))
+ return -EIO;
+
if (get_fuse_conn(inode)->writeback_cache) {
/* Update size (EOF optimization) and mode (SUID clearing) */
err = fuse_update_attributes(mapping->host, NULL, file, NULL);
@@ -1415,7 +1424,7 @@ static ssize_t __fuse_direct_read(struct
struct file *file = io->file;
struct inode *inode = file_inode(file);

- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
return -EIO;

res = fuse_direct_io(io, iter, ppos, 0);
@@ -1438,7 +1447,7 @@ static ssize_t fuse_direct_write_iter(st
struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(file);
ssize_t res;

- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
return -EIO;

/* Don't allow parallel writes to the same file */
@@ -1911,7 +1920,7 @@ static int fuse_writepages(struct addres
int err;

err = -EIO;
- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
goto out;

data.inode = inode;
@@ -2687,7 +2696,7 @@ long fuse_ioctl_common(struct file *file
if (!fuse_allow_current_process(fc))
return -EACCES;

- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
return -EIO;

return fuse_do_ioctl(file, cmd, arg, flags);
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -115,6 +115,8 @@ enum {
FUSE_I_INIT_RDPLUS,
/** An operation changing file size is in progress */
FUSE_I_SIZE_UNSTABLE,
+ /* Bad inode */
+ FUSE_I_BAD,
};

struct fuse_conn;
@@ -688,6 +690,16 @@ static inline u64 get_node_id(struct ino
return get_fuse_inode(inode)->nodeid;
}

+static inline void fuse_make_bad(struct inode *inode)
+{
+ set_bit(FUSE_I_BAD, &get_fuse_inode(inode)->state);
+}
+
+static inline bool fuse_is_bad(struct inode *inode)
+{
+ return unlikely(test_bit(FUSE_I_BAD, &get_fuse_inode(inode)->state));
+}
+
/** Device operations */
extern const struct file_operations fuse_dev_operations;

--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -316,7 +316,7 @@ struct inode *fuse_iget(struct super_blo
unlock_new_inode(inode);
} else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
/* Inode has changed type, any I/O on the old should fail */
- make_bad_inode(inode);
+ fuse_make_bad(inode);
iput(inode);
goto retry;
}
--- a/fs/fuse/xattr.c
+++ b/fs/fuse/xattr.c
@@ -113,6 +113,9 @@ ssize_t fuse_listxattr(struct dentry *en
struct fuse_getxattr_out outarg;
ssize_t ret;

+ if (fuse_is_bad(inode))
+ return -EIO;
+
if (!fuse_allow_current_process(fc))
return -EACCES;

@@ -178,6 +181,9 @@ static int fuse_xattr_get(const struct x
struct dentry *dentry, struct inode *inode,
const char *name, void *value, size_t size)
{
+ if (fuse_is_bad(inode))
+ return -EIO;
+
return fuse_getxattr(inode, name, value, size);
}

@@ -186,6 +192,9 @@ static int fuse_xattr_set(const struct x
const char *name, const void *value, size_t size,
int flags)
{
+ if (fuse_is_bad(inode))
+ return -EIO;
+
if (!value)
return fuse_removexattr(inode, name);


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