From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B15E741C72; Thu, 30 Jul 2026 16:10:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785427849; cv=none; b=VGqIFA8R3rXrL+ZtfCBbD5yS7381lc9X4882NyxmFDKE+n3aXDEfp9zhUeRe2vmA7ENrhMdlI+ql9os6yaTUUPLT8pgJm4CDHbGVIu+MWYSGpUmvkQlmQr+ybWlohihd+Div/IuXF8VApLX3fiQan1WSh4SVA2FyQT+8RPuu/s8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785427849; c=relaxed/simple; bh=SvzWc9XfmZoVy6+xG6+2PJlmmfNkD6lx63H1HwgokTE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=f1IQ9lRXitx72pBlPM8SceuOhZNTodwRpwncufQCnVg4KiG48Ol6jVX9eovqExyfA69lso6R371AGuvocvAt415zkG5+SBIKWeIJrorcpnTcdtKoctIemkBfA0gXQMrqcbnCRjI2Ifcq5m+iu/5ezYJMqIXYHHw4wRDzg0oiUCk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=LIU9Kysz; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="LIU9Kysz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 12C651F000E9; Thu, 30 Jul 2026 16:10:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1785427848; bh=N8hPUb1pAnlKrOBpQWZ+g0oYahP84lC4tQralWg1Ang=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=LIU9KyszmbEb3srr4J8qeHhefG6iuv0rjQKdCwAbIMYRZCceK/YKSP7abLrGCtTmk oyKpEGD1mBh1QFxxjTFlKiP5jbinSP3qZYNH78t/tJYnY5CM+0etogy4fJ6I+6yEI3 mhbgwXEihvAWGSh3SoKtq/cuv1/Y4WJNKj+ThtQ4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sashiko , Christoph Hellwig , Eric Biggers Subject: [PATCH 6.6 313/484] fscrypt: Add missing superblock check in find_or_insert_direct_key() Date: Thu, 30 Jul 2026 16:13:30 +0200 Message-ID: <20260730141430.287765895@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260730141423.392222816@linuxfoundation.org> References: <20260730141423.392222816@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Biggers commit b5fa40226e71c17847b9ff2816c6ca4133d0d994 upstream. The legacy 'fscrypt_direct_keys' table caches master keys that are used by v1 encryption policies that have FSCRYPT_POLICY_FLAG_DIRECT_KEY. It's just a global table for all filesystems (since the keys can be provided by the legacy process-subscribed keyrings mechanism, which makes it difficult to reuse super_block::s_master_keys). The entries in it ('struct fscrypt_direct_key') do contain a super_block pointer, though, for passing to fscrypt_destroy_inline_crypt_key() when the last inode that references the key is evicted. However, when finding the fscrypt_direct_key for an inode, we weren't actually comparing the super_block pointer. As a result, inodes with different super_blocks could point to the same fscrypt_direct_key. That could extend the lifetime of a fscrypt_direct_key beyond the super_block it points to, causing a use-after-free later. Fix this by creating distinct fscrypt_direct_key structs for distinct super_block structs. Note that this problem doesn't exist in the v2 policy equivalent ("per-mode keys"), since the data structures there are per super_block. Fixes: 22e9947a4b2b ("fscrypt: stop holding extra request_queue references") Cc: stable@vger.kernel.org Reported-by: Sashiko Closes: https://sashiko.dev/#/patchset/20260717044303.425265-1-ebiggers%40kernel.org Reviewed-by: Christoph Hellwig Link: https://patch.msgid.link/20260719033120.122120-1-ebiggers@kernel.org Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman --- fs/crypto/keysetup_v1.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- a/fs/crypto/keysetup_v1.c +++ b/fs/crypto/keysetup_v1.c @@ -199,13 +199,19 @@ find_or_insert_direct_key(struct fscrypt if (memcmp(ci->ci_policy.v1.master_key_descriptor, dk->dk_descriptor, FSCRYPT_KEY_DESCRIPTOR_SIZE) != 0) continue; + /* The sb is used at eviction time, so it must be the same. */ + if (ci->ci_inode->i_sb != dk->dk_sb) + continue; if (ci->ci_mode != dk->dk_mode) continue; if (!fscrypt_is_key_prepared(&dk->dk_key, ci)) continue; if (crypto_memneq(raw_key, dk->dk_raw, ci->ci_mode->keysize)) continue; - /* using existing tfm with same (descriptor, mode, raw_key) */ + /* + * Use an existing prepared key with the same (descriptor, sb, + * mode, inlinecrypt, raw_key) combination. + */ refcount_inc(&dk->dk_refcount); spin_unlock(&fscrypt_direct_keys_lock); free_direct_key(to_insert);