From: Miklos Szeredi <mszeredi@redhat.com>
Date: Thu, 10 Dec 2020 15:33:14 +0100
Subject: fuse: fix bad inode
Git-commit: 5d069dbe8aaf2a197142558b6fb2978189ba3454
Patch-mainline: v5.11-rc1
References: bsc#1184211 CVE-2020-36322
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>
[luis:
- Adjust context
- Modify fuse_readpages() instead of fuse_readahead() since we don't have
commit 76a0294eb19b ("fuse: convert from readpages to readahead")]
Acked-by: Luis Henriques <lhenriques@suse.com>
---
fs/fuse/acl.c | 6 ++++++
fs/fuse/dir.c | 37 ++++++++++++++++++++++++++++++++-----
fs/fuse/file.c | 19 +++++++++++--------
fs/fuse/fuse_i.h | 12 ++++++++++++
fs/fuse/inode.c | 4 ++--
fs/fuse/readdir.c | 4 ++--
fs/fuse/xattr.c | 9 +++++++++
7 files changed, 74 insertions(+), 17 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
@@ -167,7 +167,7 @@ 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)) {
@@ -339,6 +339,9 @@ 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);
@@ -481,6 +484,9 @@ 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))
@@ -529,6 +535,9 @@ 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;
@@ -656,6 +665,9 @@ 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;
@@ -692,6 +704,9 @@ 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;
@@ -770,6 +785,9 @@ 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;
@@ -905,7 +923,7 @@ 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,
@@ -1107,6 +1125,9 @@ 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;
@@ -1204,7 +1225,7 @@ static const char *fuse_get_link(struct
int err;
err = -EIO;
- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
goto out_err;
if (fc->cache_symlinks)
@@ -1252,7 +1273,7 @@ static int fuse_dir_fsync(struct file *f
struct fuse_conn *fc = get_fuse_conn(inode);
int err;
- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
return -EIO;
if (fc->no_fsyncdir)
@@ -1529,7 +1550,7 @@ 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;
}
@@ -1585,6 +1606,9 @@ 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;
@@ -1643,6 +1667,9 @@ static int fuse_getattr(const struct pat
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;
--- 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;
@@ -420,7 +423,7 @@ 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)
@@ -485,7 +488,7 @@ static int fuse_fsync(struct file *file,
struct fuse_conn *fc = get_fuse_conn(inode);
int err;
- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
return -EIO;
inode_lock(inode);
@@ -784,7 +787,7 @@ 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);
@@ -911,7 +914,7 @@ static int fuse_readpages(struct file *f
unsigned int nr_alloc = min_t(unsigned int, nr_pages, fc->max_pages);
err = -EIO;
- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
goto out;
data.file = file;
@@ -1497,7 +1500,7 @@ static ssize_t fuse_file_read_iter(struc
struct file *file = iocb->ki_filp;
struct fuse_file *ff = file->private_data;
- if (is_bad_inode(file_inode(file)))
+ if (fuse_is_bad(file_inode(file)))
return -EIO;
if (!(ff->open_flags & FOPEN_DIRECT_IO))
@@ -1511,7 +1514,7 @@ static ssize_t fuse_file_write_iter(stru
struct file *file = iocb->ki_filp;
struct fuse_file *ff = file->private_data;
- if (is_bad_inode(file_inode(file)))
+ if (fuse_is_bad(file_inode(file)))
return -EIO;
if (!(ff->open_flags & FOPEN_DIRECT_IO))
@@ -1997,7 +2000,7 @@ 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;
@@ -2787,7 +2790,7 @@ 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
@@ -161,6 +161,8 @@ 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;
@@ -794,6 +796,16 @@ static inline u64 fuse_get_attr_version(
return atomic64_read(&fc->attr_version);
}
+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
@@ -125,7 +125,7 @@ static void fuse_evict_inode(struct inod
fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup);
fi->forget = NULL;
}
- if (S_ISREG(inode->i_mode) && !is_bad_inode(inode)) {
+ if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) {
WARN_ON(!list_empty(&fi->write_files));
WARN_ON(!list_empty(&fi->queued_writes));
}
@@ -314,7 +314,7 @@ 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/readdir.c
+++ b/fs/fuse/readdir.c
@@ -207,7 +207,7 @@ retry:
dput(dentry);
goto retry;
}
- if (is_bad_inode(inode)) {
+ if (fuse_is_bad(inode)) {
dput(dentry);
return -EIO;
}
@@ -554,7 +554,7 @@ int fuse_readdir(struct file *file, stru
struct inode *inode = file_inode(file);
int err;
- if (is_bad_inode(inode))
+ if (fuse_is_bad(inode))
return -EIO;
mutex_lock(&ff->readdir.lock);
--- 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);