fuse: verify attributes

commit eb59bd17d2fa6e5e84fba61a5ebdea984222e6d5 upstream.

If a filesystem returns negative inode sizes, future reads on the file were
causing the cpu to spin on truncate_pagecache.

Create a helper to validate the attributes.  This now does two things:

 - check the file mode
 - check if the file size fits in i_size without overflowing

Reported-by: Arijit Banerjee <arijit@rubrik.com>
Fixes: d8a5ba45457e ("[PATCH] FUSE - core")
Cc: <stable@vger.kernel.org> # v2.6.14
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index f84477d..485a553 100644 (file)
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -240,7 +240,8 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
                kfree(forget);
                if (ret == -ENOMEM)
                        goto out;
-               if (ret || (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
+               if (ret || fuse_invalid_attr(&outarg.attr) ||
+                   (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
                        goto invalid;
 
                fuse_change_attributes(inode, &outarg.attr,
@@ -282,6 +283,12 @@ int fuse_valid_type(int m)
                S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m);
 }
 
+bool fuse_invalid_attr(struct fuse_attr *attr)
+{
+       return !fuse_valid_type(attr->mode) ||
+               attr->size > LLONG_MAX;
+}
+
 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
                     struct fuse_entry_out *outarg, struct inode **inode)
 {
@@ -313,7 +320,7 @@ int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
        err = -EIO;
        if (!outarg->nodeid)
                goto out_put_forget;
-       if (!fuse_valid_type(outarg->attr.mode))
+       if (fuse_invalid_attr(&outarg->attr))
                goto out_put_forget;
 
        *inode = fuse_iget(sb, outarg->nodeid, outarg->generation,
@@ -433,7 +440,8 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry,
                goto out_free_ff;
 
        err = -EIO;
-       if (!S_ISREG(outentry.attr.mode) || invalid_nodeid(outentry.nodeid))
+       if (!S_ISREG(outentry.attr.mode) || invalid_nodeid(outentry.nodeid) ||
+           fuse_invalid_attr(&outentry.attr))
                goto out_free_ff;
 
        ff->fh = outopen.fh;
@@ -539,7 +547,7 @@ static int create_new_entry(struct fuse_conn *fc, struct fuse_args *args,
                goto out_put_forget_req;
 
        err = -EIO;
-       if (invalid_nodeid(outarg.nodeid))
+       if (invalid_nodeid(outarg.nodeid) || fuse_invalid_attr(&outarg.attr))
                goto out_put_forget_req;
 
        if ((outarg.attr.mode ^ mode) & S_IFMT)
@@ -893,7 +901,8 @@ static int fuse_do_getattr(struct inode *inode, struct kstat *stat,
        args.out.args[0].value = &outarg;
        err = fuse_simple_request(fc, &args);
        if (!err) {
-               if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
+               if (fuse_invalid_attr(&outarg.attr) ||
+                   (inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
                        make_bad_inode(inode);
                        err = -EIO;
                } else {
@@ -1198,7 +1207,7 @@ static int fuse_direntplus_link(struct file *file,
 
        if (invalid_nodeid(o->nodeid))
                return -EIO;
-       if (!fuse_valid_type(o->attr.mode))
+       if (fuse_invalid_attr(&o->attr))
                return -EIO;
 
        fc = get_fuse_conn(dir);
@@ -1670,7 +1679,8 @@ int fuse_do_setattr(struct inode *inode, struct iattr *attr,
                goto error;
        }
 
-       if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
+       if (fuse_invalid_attr(&outarg.attr) ||
+           (inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
                make_bad_inode(inode);
                err = -EIO;
                goto error;

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index c6eb35a..8844007 100644 (file)
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -887,6 +887,8 @@ void fuse_ctl_remove_conn(struct fuse_conn *fc);
  */
 int fuse_valid_type(int m);
 
+bool fuse_invalid_attr(struct fuse_attr *attr);
+
 /**
  * Is current process allowed to perform filesystem operation?
  */