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Subject[PATCH 3.16 087/148] fuse: verify attributes
3.16.82-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Miklos Szeredi <mszeredi@redhat.com>

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")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
fs/fuse/dir.c | 24 +++++++++++++++++-------
fs/fuse/fuse_i.h | 2 ++
2 files changed, 19 insertions(+), 7 deletions(-)

--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -250,7 +250,8 @@ static int fuse_dentry_revalidate(struct
spin_unlock(&fc->lock);
}
kfree(forget);
- if (err || (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
+ if (err || fuse_invalid_attr(&outarg.attr) ||
+ (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
goto invalid;

fuse_change_attributes(inode, &outarg.attr,
@@ -295,6 +296,12 @@ 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)
{
@@ -334,7 +341,7 @@ int fuse_lookup_name(struct super_block
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,
@@ -464,7 +471,8 @@ static int fuse_create_open(struct inode
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;

fuse_put_request(fc, req);
@@ -580,7 +588,7 @@ static int create_new_entry(struct fuse_
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)
@@ -971,7 +979,8 @@ static int fuse_do_getattr(struct inode
err = req->out.h.error;
fuse_put_request(fc, req);
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 {
@@ -1282,7 +1291,7 @@ static int fuse_direntplus_link(struct f

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);
@@ -1794,7 +1803,8 @@ int fuse_do_setattr(struct dentry *dentr
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;
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -828,6 +828,8 @@ void fuse_ctl_remove_conn(struct fuse_co
*/
int fuse_valid_type(int m);

+bool fuse_invalid_attr(struct fuse_attr *attr);
+
/**
* Is current process allowed to perform filesystem operation?
*/
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