From eb59bd17d2fa6e5e84fba61a5ebdea984222e6d5 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Tue, 12 Nov 2019 11:49:04 +0100 Subject: fuse: verify attributes 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 Fixes: d8a5ba45457e ("[PATCH] FUSE - core") Cc: # v2.6.14 Signed-off-by: Miklos Szeredi --- fs/fuse/dir.c | 22 ++++++++++++++++------ fs/fuse/fuse_i.h | 2 ++ fs/fuse/readdir.c | 2 +- 3 files changed, 19 insertions(+), 7 deletions(-) diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index 54d638f9ba1c..ca4ddbe21ec0 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -248,7 +248,8 @@ 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; forget_all_cached_acls(inode); @@ -319,6 +320,12 @@ 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, const struct qstr *name, struct fuse_entry_out *outarg, struct inode **inode) { @@ -350,7 +357,7 @@ int fuse_lookup_name(struct super_block *sb, u64 nodeid, const 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, @@ -475,7 +482,8 @@ 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; @@ -583,7 +591,7 @@ 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) @@ -942,7 +950,8 @@ 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 { @@ -1563,7 +1572,8 @@ int fuse_do_setattr(struct dentry *dentry, 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 d148188cfca4..aa75e2305b75 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -989,6 +989,8 @@ 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? */ diff --git a/fs/fuse/readdir.c b/fs/fuse/readdir.c index 5c38b9d84c6e..6a40f75a0d25 100644 --- a/fs/fuse/readdir.c +++ b/fs/fuse/readdir.c @@ -184,7 +184,7 @@ 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); -- cgit v1.2.3