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 C852D3815EA; Wed, 24 Jun 2026 05:06:08 +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=1782277572; cv=none; b=pF5sI+ZyOfXnDAfI+anTp0OfMC19Y8a9QwwsrD8cBoVlaIA75kpoT43XEydsZZvH8YAOSud8H3z6KmdO3WxXdGTDjGLxrZReujG0hu6iMdxqAUWFOqkLI1kBlkjdwaIvmULtWKlyRGHFXDDJQ4A0g+ckKEbGEBHAvJP2fw2T4PI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782277572; c=relaxed/simple; bh=F3BEyrHkUB8zingX74iuKe5++ihxM3qFWZbwCcoxLwo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fuhyddmiLktjgVriBh9Qz2KfpOEjlJpNxxUacOkpRkGFvyjQ02jXBe84LOdkXRGtCT+xSm390qavN0qN3AX0XXwpZSZO1kmWdoAnD65BPinUC/HrIo7c4YuCWr7uu6p/c7WL8a/iBKqURUKIYAsXGimL1QKoQjONc7Cn+IPwpw0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GpeCtCKm; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GpeCtCKm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0D3071F00ACF; Wed, 24 Jun 2026 05:06:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782277568; bh=a0rfoABP8qHsael55vuEKeqreyLhGbch+zU0Femb/yQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=GpeCtCKm1+KxA/+JlK/TB2Z9KftZjsAVf6UKvwJoGNGTkbdRyxGyQvA+q5mEwlBrR +KRAINLa1FHIF+VDCubrC4hJJuxB+nLDsxT2QMn2MfYIjUMKoBwBqK6MT0eMSEUmaf mbaWzwJywGZlnHtONi0zVG60ACMOlo6MPRNy7F0ugzmu0Ob8pbIhfDlUgK76tEjZYI RVn34EU1I5JNgpds+MiC35nzS+c+cJx+IkM3668t9c8snK6w9yUer0gvHvjzg8nUR7 8Y2CtP5MLH9j4fgxpQwti3ZJxERRS987mZTguMVnRLtoSMyMsL3ecuwYSIE3HGiM3C umcEkdxPBMV4w== From: Eric Biggers To: linux-fscrypt@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-block@vger.kernel.org, Christoph Hellwig , Theodore Ts'o , Andreas Dilger , Baokun Li , Jan Kara , Ojaswin Mujoo , Ritesh Harjani , Zhang Yi , Jaegeuk Kim , Chao Yu , Eric Biggers Subject: [PATCH 16/16] fscrypt: Add safety checks to non-block-based en/decryption Date: Tue, 23 Jun 2026 22:03:34 -0700 Message-ID: <20260624050334.124606-17-ebiggers@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260624050334.124606-1-ebiggers@kernel.org> References: <20260624050334.124606-1-ebiggers@kernel.org> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit fscrypt_encrypt_pagecache_blocks(), fscrypt_encrypt_block_inplace(), fscrypt_decrypt_block_inplace() would dereference a NULL fscrypt_inode_info pointer if they were to be called on a file that hasn't been opened yet or on a block-based filesystem. Since they have the ability to report errors anyway, add WARN_ON_ONCE checks for this. Signed-off-by: Eric Biggers --- fs/crypto/crypto.c | 61 +++++++++++++++++++++++++++++----------------- 1 file changed, 39 insertions(+), 22 deletions(-) diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c index 27663f4d8705..c91eda62f9a4 100644 --- a/fs/crypto/crypto.c +++ b/fs/crypto/crypto.c @@ -103,35 +103,44 @@ static int fscrypt_crypt_data_unit(const struct fscrypt_inode_info *ci, fscrypt_direction_t rw, u64 index, struct page *src_page, struct page *dest_page, unsigned int len, unsigned int offs) { - struct crypto_sync_skcipher *tfm = ci->ci_enc_key.tfm; - SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm); + struct crypto_sync_skcipher *tfm; union fscrypt_iv iv; struct scatterlist dst, src; int err; + if (WARN_ON_ONCE(ci == NULL)) /* File hasn't been opened yet? */ + return -ENOKEY; + tfm = ci->ci_enc_key.tfm; + if (WARN_ON_ONCE(tfm == NULL)) /* Called on block-based filesystem? */ + return -ENOKEY; + if (WARN_ON_ONCE(len <= 0)) return -EINVAL; if (WARN_ON_ONCE(len % FSCRYPT_CONTENTS_ALIGNMENT != 0)) return -EINVAL; fscrypt_generate_iv(&iv, index, ci); - skcipher_request_set_callback( - req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, - NULL, NULL); - sg_init_table(&dst, 1); - sg_set_page(&dst, dest_page, len, offs); - sg_init_table(&src, 1); - sg_set_page(&src, src_page, len, offs); - skcipher_request_set_crypt(req, &src, &dst, len, &iv); - if (rw == FS_DECRYPT) - err = crypto_skcipher_decrypt(req); - else - err = crypto_skcipher_encrypt(req); + { + SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm); + skcipher_request_set_callback(req, + CRYPTO_TFM_REQ_MAY_BACKLOG | + CRYPTO_TFM_REQ_MAY_SLEEP, + NULL, NULL); + sg_init_table(&dst, 1); + sg_set_page(&dst, dest_page, len, offs); + sg_init_table(&src, 1); + sg_set_page(&src, src_page, len, offs); + skcipher_request_set_crypt(req, &src, &dst, len, &iv); + if (rw == FS_DECRYPT) + err = crypto_skcipher_decrypt(req); + else + err = crypto_skcipher_encrypt(req); + } if (err) fscrypt_err(ci->ci_inode, "%scryption failed for data unit %llu: %d", (rw == FS_DECRYPT ? "De" : "En"), index, err); return err; @@ -151,11 +160,11 @@ static int fscrypt_crypt_data_unit(const struct fscrypt_inode_info *ci, * * In the bounce page, the ciphertext data will be located at the same offset at * which the plaintext data was located in the source page. Any other parts of * the bounce page will be left uninitialized. * - * This is for use by the filesystem's ->writepages() method. + * This is for use by the ->writepages() method of non-block-based filesystems. * * The bounce page allocation is mempool-backed, so it will always succeed when * @gfp_flags includes __GFP_DIRECT_RECLAIM, e.g. when it's GFP_NOFS. However, * only the first page of each bio can be allocated this way. To prevent * deadlocks, for any additional pages a mask like GFP_NOWAIT must be used. @@ -165,18 +174,24 @@ static int fscrypt_crypt_data_unit(const struct fscrypt_inode_info *ci, struct page *fscrypt_encrypt_pagecache_blocks(struct folio *folio, size_t len, size_t offs, gfp_t gfp_flags) { const struct inode *inode = folio->mapping->host; const struct fscrypt_inode_info *ci = fscrypt_get_inode_info_raw(inode); - const unsigned int du_bits = ci->ci_data_unit_bits; - const unsigned int du_size = 1U << du_bits; + unsigned int du_bits; + unsigned int du_size; struct page *ciphertext_page; - u64 index = ((u64)folio->index << (PAGE_SHIFT - du_bits)) + - (offs >> du_bits); + u64 index; unsigned int i; int err; + if (WARN_ON_ONCE(ci == NULL)) /* File hasn't been opened yet? */ + return ERR_PTR(-ENOKEY); + + du_bits = ci->ci_data_unit_bits; + du_size = 1U << du_bits; + index = (folio_pos(folio) + offs) >> du_bits; + VM_BUG_ON_FOLIO(folio_test_large(folio), folio); if (WARN_ON_ONCE(!folio_test_locked(folio))) return ERR_PTR(-EINVAL); if (WARN_ON_ONCE(len <= 0 || !IS_ALIGNED(len | offs, du_size))) @@ -213,11 +228,12 @@ EXPORT_SYMBOL(fscrypt_encrypt_pagecache_blocks); * * Encrypt a possibly-compressed filesystem block that is located in an * arbitrary page, not necessarily in the original pagecache page. The @inode * and @lblk_num must be specified, as they can't be determined from @page. * - * This is not compatible with fscrypt_operations::supports_subblock_data_units. + * This function only supports non-block-based filesystems that don't support + * sub-block data units (as indicated by the fscrypt_operations fields). * * Return: 0 on success; -errno on failure */ int fscrypt_encrypt_block_inplace(const struct inode *inode, struct page *page, unsigned int len, unsigned int offs, @@ -243,11 +259,12 @@ EXPORT_SYMBOL(fscrypt_encrypt_block_inplace); * * Decrypt a possibly-compressed filesystem block that is located in an * arbitrary page, not necessarily in the original pagecache page. The @inode * and @lblk_num must be specified, as they can't be determined from @page. * - * This is not compatible with fscrypt_operations::supports_subblock_data_units. + * This function only supports non-block-based filesystems that don't support + * sub-block data units (as indicated by the fscrypt_operations fields). * * Return: 0 on success; -errno on failure */ int fscrypt_decrypt_block_inplace(const struct inode *inode, struct page *page, unsigned int len, unsigned int offs, @@ -273,11 +290,11 @@ EXPORT_SYMBOL(fscrypt_decrypt_block_inplace); int fscrypt_initialize(struct super_block *sb) { mempool_t *pool; /* pairs with smp_store_release() below */ - if (likely(smp_load_acquire(&fscrypt_bounce_page_pool))) + if (smp_load_acquire(&fscrypt_bounce_page_pool)) return 0; /* No need to allocate a bounce page pool if this FS won't use it. */ if (!sb->s_cop->needs_bounce_pages) return 0; -- 2.54.0