ext4 crypto: don't allocate a page when encrypting/decrypting file names
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o
Родитель
5b643f9ce3
Коммит
d229959072
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@ -65,9 +65,9 @@ static int ext4_fname_encrypt(struct ext4_fname_crypto_ctx *ctx,
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struct crypto_ablkcipher *tfm = ctx->ctfm;
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int res = 0;
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char iv[EXT4_CRYPTO_BLOCK_SIZE];
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struct scatterlist sg[1];
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struct scatterlist src_sg, dst_sg;
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int padding = 4 << (ctx->flags & EXT4_POLICY_FLAGS_PAD_MASK);
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char *workbuf;
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char *workbuf, buf[32], *alloc_buf = NULL;
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if (iname->len <= 0 || iname->len > ctx->lim)
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return -EIO;
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@ -78,20 +78,27 @@ static int ext4_fname_encrypt(struct ext4_fname_crypto_ctx *ctx,
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ciphertext_len = (ciphertext_len > ctx->lim)
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? ctx->lim : ciphertext_len;
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if (ciphertext_len <= sizeof(buf)) {
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workbuf = buf;
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} else {
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alloc_buf = kmalloc(ciphertext_len, GFP_NOFS);
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if (!alloc_buf)
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return -ENOMEM;
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workbuf = alloc_buf;
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}
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/* Allocate request */
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req = ablkcipher_request_alloc(tfm, GFP_NOFS);
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if (!req) {
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printk_ratelimited(
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KERN_ERR "%s: crypto_request_alloc() failed\n", __func__);
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kfree(alloc_buf);
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return -ENOMEM;
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}
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ablkcipher_request_set_callback(req,
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CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
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ext4_dir_crypt_complete, &ecr);
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/* Map the workpage */
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workbuf = kmap(ctx->workpage);
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/* Copy the input */
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memcpy(workbuf, iname->name, iname->len);
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if (iname->len < ciphertext_len)
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@ -101,21 +108,16 @@ static int ext4_fname_encrypt(struct ext4_fname_crypto_ctx *ctx,
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memset(iv, 0, EXT4_CRYPTO_BLOCK_SIZE);
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/* Create encryption request */
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sg_init_table(sg, 1);
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sg_set_page(sg, ctx->workpage, PAGE_SIZE, 0);
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ablkcipher_request_set_crypt(req, sg, sg, ciphertext_len, iv);
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sg_init_one(&src_sg, workbuf, ciphertext_len);
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sg_init_one(&dst_sg, oname->name, ciphertext_len);
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ablkcipher_request_set_crypt(req, &src_sg, &dst_sg, ciphertext_len, iv);
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res = crypto_ablkcipher_encrypt(req);
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if (res == -EINPROGRESS || res == -EBUSY) {
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BUG_ON(req->base.data != &ecr);
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wait_for_completion(&ecr.completion);
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res = ecr.res;
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}
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if (res >= 0) {
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/* Copy the result to output */
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memcpy(oname->name, workbuf, ciphertext_len);
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res = ciphertext_len;
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}
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kunmap(ctx->workpage);
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kfree(alloc_buf);
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ablkcipher_request_free(req);
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if (res < 0) {
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printk_ratelimited(
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@ -139,11 +141,10 @@ static int ext4_fname_decrypt(struct ext4_fname_crypto_ctx *ctx,
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struct ext4_str tmp_in[2], tmp_out[1];
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struct ablkcipher_request *req = NULL;
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DECLARE_EXT4_COMPLETION_RESULT(ecr);
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struct scatterlist sg[1];
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struct scatterlist src_sg, dst_sg;
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struct crypto_ablkcipher *tfm = ctx->ctfm;
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int res = 0;
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char iv[EXT4_CRYPTO_BLOCK_SIZE];
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char *workbuf;
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if (iname->len <= 0 || iname->len > ctx->lim)
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return -EIO;
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@ -163,31 +164,19 @@ static int ext4_fname_decrypt(struct ext4_fname_crypto_ctx *ctx,
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CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
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ext4_dir_crypt_complete, &ecr);
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/* Map the workpage */
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workbuf = kmap(ctx->workpage);
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/* Copy the input */
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memcpy(workbuf, iname->name, iname->len);
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/* Initialize IV */
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memset(iv, 0, EXT4_CRYPTO_BLOCK_SIZE);
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/* Create encryption request */
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sg_init_table(sg, 1);
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sg_set_page(sg, ctx->workpage, PAGE_SIZE, 0);
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ablkcipher_request_set_crypt(req, sg, sg, iname->len, iv);
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sg_init_one(&src_sg, iname->name, iname->len);
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sg_init_one(&dst_sg, oname->name, oname->len);
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ablkcipher_request_set_crypt(req, &src_sg, &dst_sg, iname->len, iv);
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res = crypto_ablkcipher_decrypt(req);
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if (res == -EINPROGRESS || res == -EBUSY) {
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BUG_ON(req->base.data != &ecr);
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wait_for_completion(&ecr.completion);
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res = ecr.res;
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}
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if (res >= 0) {
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/* Copy the result to output */
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memcpy(oname->name, workbuf, iname->len);
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res = iname->len;
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}
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kunmap(ctx->workpage);
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ablkcipher_request_free(req);
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if (res < 0) {
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printk_ratelimited(
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@ -267,8 +256,6 @@ void ext4_free_fname_crypto_ctx(struct ext4_fname_crypto_ctx *ctx)
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crypto_free_ablkcipher(ctx->ctfm);
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if (ctx->htfm && !IS_ERR(ctx->htfm))
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crypto_free_hash(ctx->htfm);
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if (ctx->workpage && !IS_ERR(ctx->workpage))
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__free_page(ctx->workpage);
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kfree(ctx);
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}
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@ -322,7 +309,6 @@ struct ext4_fname_crypto_ctx *ext4_alloc_fname_crypto_ctx(
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ctx->ctfm_key_is_ready = 0;
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ctx->ctfm = NULL;
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ctx->htfm = NULL;
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ctx->workpage = NULL;
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return ctx;
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}
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@ -390,24 +376,6 @@ struct ext4_fname_crypto_ctx *ext4_get_fname_crypto_ctx(
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ext4_put_fname_crypto_ctx(&ctx);
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return ERR_PTR(-ENOMEM);
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}
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if (ctx->workpage == NULL)
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ctx->workpage = alloc_page(GFP_NOFS);
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if (IS_ERR(ctx->workpage)) {
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res = PTR_ERR(ctx->workpage);
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printk(
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KERN_DEBUG "%s: error (%d) allocating work page\n",
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__func__, res);
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ctx->workpage = NULL;
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ext4_put_fname_crypto_ctx(&ctx);
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return ERR_PTR(res);
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}
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if (ctx->workpage == NULL) {
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printk(
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KERN_DEBUG "%s: could not allocate work page\n",
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__func__);
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ext4_put_fname_crypto_ctx(&ctx);
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return ERR_PTR(-ENOMEM);
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}
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ctx->lim = max_ciphertext_len;
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crypto_ablkcipher_clear_flags(ctx->ctfm, ~0);
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crypto_tfm_set_flags(crypto_ablkcipher_tfm(ctx->ctfm),
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@ -247,9 +247,12 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
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get_dtype(sb, de->file_type)))
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goto done;
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} else {
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int save_len = fname_crypto_str.len;
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/* Directory is encrypted */
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err = ext4_fname_disk_to_usr(enc_ctx,
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NULL, de, &fname_crypto_str);
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fname_crypto_str.len = save_len;
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if (err < 0)
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goto errout;
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if (!dir_emit(ctx,
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@ -123,10 +123,8 @@ struct ext4_str {
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struct ext4_fname_crypto_ctx {
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u32 lim;
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char tmp_buf[EXT4_CRYPTO_BLOCK_SIZE];
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struct crypto_ablkcipher *ctfm;
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struct crypto_hash *htfm;
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struct page *workpage;
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struct ext4_encryption_key key;
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unsigned flags : 8;
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unsigned has_valid_key : 1;
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@ -998,6 +998,8 @@ static int htree_dirblock_to_tree(struct file *dir_file,
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hinfo->hash, hinfo->minor_hash, de,
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&tmp_str);
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} else {
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int save_len = fname_crypto_str.len;
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/* Directory is encrypted */
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err = ext4_fname_disk_to_usr(ctx, hinfo, de,
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&fname_crypto_str);
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@ -1008,6 +1010,7 @@ static int htree_dirblock_to_tree(struct file *dir_file,
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err = ext4_htree_store_dirent(dir_file,
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hinfo->hash, hinfo->minor_hash, de,
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&fname_crypto_str);
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fname_crypto_str.len = save_len;
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}
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if (err != 0) {
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count = err;
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@ -3126,6 +3129,7 @@ static int ext4_symlink(struct inode *dir,
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istr.name = (const unsigned char *) symname;
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istr.len = len;
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ostr.name = sd->encrypted_path;
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ostr.len = disk_link.len;
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err = ext4_fname_usr_to_disk(ctx, &istr, &ostr);
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ext4_put_fname_crypto_ctx(&ctx);
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if (err < 0)
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@ -74,6 +74,7 @@ static void *ext4_follow_link(struct dentry *dentry, struct nameidata *nd)
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goto errout;
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}
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pstr.name = paddr;
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pstr.len = plen;
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res = _ext4_fname_disk_to_usr(ctx, NULL, &cstr, &pstr);
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if (res < 0)
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goto errout;
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