From: Al Viro <viro@zeniv.linux.org.uk>
To: Kees Cook <keescook@chromium.org>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>,
Tony Luck <tony.luck@intel.com>,
linux-hardening@vger.kernel.org,
Christian Brauner <brauner@kernel.org>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 5/5] pstore: inode: Use cleanup.h for struct pstore_private
Date: Sat, 2 Dec 2023 22:27:06 +0000 [thread overview]
Message-ID: <20231202222706.GT38156@ZenIV> (raw)
In-Reply-To: <20231202212217.243710-5-keescook@chromium.org>
On Sat, Dec 02, 2023 at 01:22:15PM -0800, Kees Cook wrote:
> static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
> {
> @@ -338,9 +339,8 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
> {
> struct dentry *dentry;
> struct inode *inode __free(iput) = NULL;
> - int rc = 0;
> char name[PSTORE_NAMELEN];
> - struct pstore_private *private, *pos;
> + struct pstore_private *private __free(pstore_private) = NULL, *pos;
> size_t size = record->size + record->ecc_notice_size;
>
> if (WARN_ON(!inode_is_locked(d_inode(root))))
> @@ -356,7 +356,6 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
> return -EEXIST;
> }
>
> - rc = -ENOMEM;
> inode = pstore_get_inode(root->d_sb);
> if (!inode)
> return -ENOMEM;
> @@ -373,7 +372,7 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
>
> dentry = d_alloc_name(root, name);
> if (!dentry)
> - goto fail_private;
> + return -ENOMEM;
>
> private->dentry = dentry;
> private->record = record;
> @@ -386,13 +385,9 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
>
> d_add(dentry, no_free_ptr(inode));
>
> - list_add(&private->list, &records_list);
> + list_add(&(no_free_ptr(private))->list, &records_list);
That's really brittle. It critically depends upon having no failure
exits past the assignment to ->i_private; once you've done that,
you have transferred the ownership of that thing to the inode
(look at your ->evict_inode()). But you can't say
inode->i_private = no_free_ptr(private);
since you are using private past that point.
next prev parent reply other threads:[~2023-12-02 22:27 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-02 21:22 [PATCH 0/5] pstore: Initial use of cleanup.h Kees Cook
2023-12-02 21:22 ` [PATCH 1/5] pstore: inode: Convert kfree() usage to __free(kfree) Kees Cook
2023-12-02 21:22 ` [PATCH 2/5] pstore: inode: Convert mutex usage to guard(mutex) Kees Cook
2023-12-05 7:01 ` Dave Chinner
2023-12-02 21:22 ` [PATCH 3/5] fs: Add DEFINE_FREE for struct inode Kees Cook
2023-12-02 21:28 ` Al Viro
2023-12-02 21:34 ` Kees Cook
2023-12-02 21:42 ` Al Viro
2023-12-02 21:45 ` Al Viro
2023-12-05 11:38 ` Christian Brauner
2023-12-02 21:22 ` [PATCH 4/5] pstore: inode: Use __free(iput) for inode allocations Kees Cook
2023-12-02 21:22 ` [PATCH 5/5] pstore: inode: Use cleanup.h for struct pstore_private Kees Cook
2023-12-02 22:27 ` Al Viro [this message]
2023-12-05 0:54 ` Kees Cook
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