From: Miklos Szeredi <mszeredi@xxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Tested-by: Jan Kara <jack@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
[adjusted for missing fs/fuse/readdir.c and changes in fuse_evict_inode() in 4.14]
Signed-off-by: Samuel Mendoza-Jonas <samjonas@xxxxxxxxxx>
---
fs/fuse/acl.c | 6 ++++++
fs/fuse/dir.c | 37 ++++++++++++++++++++++++++++++++-----
fs/fuse/file.c | 21 +++++++++++++++------
fs/fuse/fuse_i.h | 12 ++++++++++++
fs/fuse/inode.c | 2 +-
fs/fuse/xattr.c | 9 +++++++++
6 files changed, 75 insertions(+), 12 deletions(-)
diff --git a/fs/fuse/acl.c b/fs/fuse/acl.c
index ec85765502f1..990529da5354 100644
--- a/fs/fuse/acl.c
+++ b/fs/fuse/acl.c
@@ -19,6 +19,9 @@ struct posix_acl *fuse_get_acl(struct inode *inode, int type)
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, struct posix_acl *acl, int type)
const char *name;
int ret;
+ if (fuse_is_bad(inode))
+ return -EIO;
+
if (!fc->posix_acl || fc->no_setxattr)
return -EOPNOTSUPP;
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index b8d13b69583c..e7220fbd2d41 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -187,7 +187,7 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
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 inode *dir, struct dentry *entry,
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 *dir, struct dentry *entry,
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_conn *fc, struct fuse_args *args,
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 dentry *entry)
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 dentry *entry)
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 *olddir, struct dentry *oldent,
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 *inode, struct kstat *stat,
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,
@@ -1110,6 +1128,9 @@ static int fuse_permission(struct inode *inode, int mask)
bool refreshed = false;
int err = 0;
+ if (fuse_is_bad(inode))
+ return -EIO;
+
if (!fuse_allow_current_process(fc))
return -EACCES;
@@ -1247,7 +1268,7 @@ static int fuse_direntplus_link(struct file *file,
dput(dentry);
goto retry;
}
- if (is_bad_inode(inode)) {
+ if (fuse_is_bad(inode)) {
dput(dentry);
return -EIO;
}
@@ -1345,7 +1366,7 @@ static int fuse_readdir(struct file *file, struct dir_context *ctx)
u64 attr_version = 0;
bool locked;
- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
return -EIO;
req = fuse_get_req(fc, 1);
@@ -1703,7 +1724,7 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
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;
}
@@ -1759,6 +1780,9 @@ static int fuse_setattr(struct dentry *entry, struct iattr *attr)
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;
@@ -1817,6 +1841,9 @@ static int fuse_getattr(const struct path *path, struct kstat *stat,
struct inode *inode = d_inode(path->dentry);
struct fuse_conn *fc = get_fuse_conn(inode);
+ if (fuse_is_bad(inode))
+ return -EIO;
+
if (!fuse_allow_current_process(fc))
return -EACCES;
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 4238939af2fe..0fb5466d5b09 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -206,6 +206,9 @@ int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
fc->atomic_o_trunc &&
fc->writeback_cache;
+ if (fuse_is_bad(inode))
+ return -EIO;
+
err = generic_file_open(inode, file);
if (err)
return err;
@@ -407,7 +410,7 @@ static int fuse_flush(struct file *file, fl_owner_t id)
struct fuse_flush_in inarg;
int err;
- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
return -EIO;
if (fc->no_flush)
@@ -455,7 +458,7 @@ int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
struct fuse_fsync_in inarg;
int err;
- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
return -EIO;
inode_lock(inode);
@@ -770,7 +773,7 @@ static int fuse_readpage(struct file *file, struct page *page)
int err;
err = -EIO;
- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
goto out;
err = fuse_do_readpage(file, page);
@@ -897,7 +900,7 @@ static int fuse_readpages(struct file *file, struct address_space *mapping,
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;
@@ -927,6 +930,9 @@ static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
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
@@ -1184,6 +1190,9 @@ static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
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, file);
@@ -1916,7 +1925,7 @@ static int fuse_writepages(struct address_space *mapping,
int err;
err = -EIO;
- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
goto out;
data.inode = inode;
@@ -2701,7 +2710,7 @@ long fuse_ioctl_common(struct file *file, unsigned int cmd,
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);
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 338aa5e266d6..220960c9b96d 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -117,6 +117,8 @@ 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;
@@ -687,6 +689,16 @@ static inline u64 get_node_id(struct inode *inode)
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;
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index ffb61787d77a..747f7a710fb9 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -317,7 +317,7 @@ struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
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;
}
diff --git a/fs/fuse/xattr.c b/fs/fuse/xattr.c
index 3caac46b08b0..134bbc432ae6 100644
--- a/fs/fuse/xattr.c
+++ b/fs/fuse/xattr.c
@@ -113,6 +113,9 @@ ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
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 xattr_handler *handler,
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 xattr_handler *handler,
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);
--
2.25.1
