From 5de0b4d0cd153c471640b13aae6ae6d18d0a4603 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o
Date: Fri, 1 May 2015 16:56:45 -0400
Subject: ext4 crypto: simplify and speed up filename encryption

Avoid using SHA-1 when calculating the user-visible filename when the
encryption key is available, and avoid decrypting lots of filenames
when searching for a directory entry in a directory block.

Change-Id: If4655f144784978ba0305b597bfa1c8d7bb69e63
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/crypto_fname.c | 268 +++++++++++++++++++++++++------------------------
 fs/ext4/dir.c          |   2 +-
 fs/ext4/ext4.h         |   9 +-
 fs/ext4/namei.c        |  72 ++-----------
 fs/ext4/symlink.c      |   2 +-
 5 files changed, 149 insertions(+), 204 deletions(-)

(limited to 'fs/ext4')

diff --git a/fs/ext4/crypto_fname.c b/fs/ext4/crypto_fname.c
index ca2f5948c1ac..7a877e609e5f 100644
--- a/fs/ext4/crypto_fname.c
+++ b/fs/ext4/crypto_fname.c
@@ -198,106 +198,57 @@ static int ext4_fname_decrypt(struct ext4_fname_crypto_ctx *ctx,
 	return oname->len;
 }
 
+static const char *lookup_table =
+	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";
+
 /**
  * ext4_fname_encode_digest() -
  *
  * Encodes the input digest using characters from the set [a-zA-Z0-9_+].
  * The encoded string is roughly 4/3 times the size of the input string.
  */
-int ext4_fname_encode_digest(char *dst, char *src, u32 len)
+static int digest_encode(const char *src, int len, char *dst)
 {
-	static const char *lookup_table =
-		"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_+";
-	u32 current_chunk, num_chunks, i;
-	char tmp_buf[3];
-	u32 c0, c1, c2, c3;
-
-	current_chunk = 0;
-	num_chunks = len/3;
-	for (i = 0; i < num_chunks; i++) {
-		c0 = src[3*i] & 0x3f;
-		c1 = (((src[3*i]>>6)&0x3) | ((src[3*i+1] & 0xf)<<2)) & 0x3f;
-		c2 = (((src[3*i+1]>>4)&0xf) | ((src[3*i+2] & 0x3)<<4)) & 0x3f;
-		c3 = (src[3*i+2]>>2) & 0x3f;
-		dst[4*i] = lookup_table[c0];
-		dst[4*i+1] = lookup_table[c1];
-		dst[4*i+2] = lookup_table[c2];
-		dst[4*i+3] = lookup_table[c3];
-	}
-	if (i*3 < len) {
-		memset(tmp_buf, 0, 3);
-		memcpy(tmp_buf, &src[3*i], len-3*i);
-		c0 = tmp_buf[0] & 0x3f;
-		c1 = (((tmp_buf[0]>>6)&0x3) | ((tmp_buf[1] & 0xf)<<2)) & 0x3f;
-		c2 = (((tmp_buf[1]>>4)&0xf) | ((tmp_buf[2] & 0x3)<<4)) & 0x3f;
-		c3 = (tmp_buf[2]>>2) & 0x3f;
-		dst[4*i] = lookup_table[c0];
-		dst[4*i+1] = lookup_table[c1];
-		dst[4*i+2] = lookup_table[c2];
-		dst[4*i+3] = lookup_table[c3];
+	int i = 0, bits = 0, ac = 0;
+	char *cp = dst;
+
+	while (i < len) {
+		ac += (((unsigned char) src[i]) << bits);
+		bits += 8;
+		do {
+			*cp++ = lookup_table[ac & 0x3f];
+			ac >>= 6;
+			bits -= 6;
+		} while (bits >= 6);
 		i++;
 	}
-	return (i * 4);
+	if (bits)
+		*cp++ = lookup_table[ac & 0x3f];
+	return cp - dst;
 }
 
-/**
- * ext4_fname_hash() -
- *
- * This function computes the hash of the input filename, and sets the output
- * buffer to the *encoded* digest.  It returns the length of the digest as its
- * return value.  Errors are returned as negative numbers.  We trust the caller
- * to allocate sufficient memory to oname string.
- */
-static int ext4_fname_hash(struct ext4_fname_crypto_ctx *ctx,
-			   const struct ext4_str *iname,
-			   struct ext4_str *oname)
+static int digest_decode(const char *src, int len, char *dst)
 {
-	struct scatterlist sg;
-	struct hash_desc desc = {
-		.tfm = (struct crypto_hash *)ctx->htfm,
-		.flags = CRYPTO_TFM_REQ_MAY_SLEEP
-	};
-	int res = 0;
-
-	if (iname->len <= EXT4_FNAME_CRYPTO_DIGEST_SIZE) {
-		res = ext4_fname_encode_digest(oname->name, iname->name,
-					       iname->len);
-		oname->len = res;
-		return res;
-	}
-
-	sg_init_one(&sg, iname->name, iname->len);
-	res = crypto_hash_init(&desc);
-	if (res) {
-		printk(KERN_ERR
-		       "%s: Error initializing crypto hash; res = [%d]\n",
-		       __func__, res);
-		goto out;
-	}
-	res = crypto_hash_update(&desc, &sg, iname->len);
-	if (res) {
-		printk(KERN_ERR
-		       "%s: Error updating crypto hash; res = [%d]\n",
-		       __func__, res);
-		goto out;
-	}
-	res = crypto_hash_final(&desc,
-		&oname->name[EXT4_FNAME_CRYPTO_DIGEST_SIZE]);
-	if (res) {
-		printk(KERN_ERR
-		       "%s: Error finalizing crypto hash; res = [%d]\n",
-		       __func__, res);
-		goto out;
+	int i = 0, bits = 0, ac = 0;
+	const char *p;
+	char *cp = dst;
+
+	while (i < len) {
+		p = strchr(lookup_table, src[i]);
+		if (p == NULL || src[i] == 0)
+			return -2;
+		ac += (p - lookup_table) << bits;
+		bits += 6;
+		if (bits >= 8) {
+			*cp++ = ac & 0xff;
+			ac >>= 8;
+			bits -= 8;
+		}
+		i++;
 	}
-	/* Encode the digest as a printable string--this will increase the
-	 * size of the digest */
-	oname->name[0] = 'I';
-	res = ext4_fname_encode_digest(oname->name+1,
-		&oname->name[EXT4_FNAME_CRYPTO_DIGEST_SIZE],
-		EXT4_FNAME_CRYPTO_DIGEST_SIZE) + 1;
-	oname->len = res;
-out:
-	return res;
+	if (ac)
+		return -1;
+	return cp - dst;
 }
 
 /**
@@ -571,9 +522,13 @@ void ext4_fname_crypto_free_buffer(struct ext4_str *crypto_str)
  * ext4_fname_disk_to_usr() - converts a filename from disk space to user space
  */
 int _ext4_fname_disk_to_usr(struct ext4_fname_crypto_ctx *ctx,
-			   const struct ext4_str *iname,
-			   struct ext4_str *oname)
+			    struct dx_hash_info *hinfo,
+			    const struct ext4_str *iname,
+			    struct ext4_str *oname)
 {
+	char buf[24];
+	int ret;
+
 	if (ctx == NULL)
 		return -EIO;
 	if (iname->len < 3) {
@@ -587,18 +542,33 @@ int _ext4_fname_disk_to_usr(struct ext4_fname_crypto_ctx *ctx,
 	}
 	if (ctx->has_valid_key)
 		return ext4_fname_decrypt(ctx, iname, oname);
-	else
-		return ext4_fname_hash(ctx, iname, oname);
+
+	if (iname->len <= EXT4_FNAME_CRYPTO_DIGEST_SIZE) {
+		ret = digest_encode(iname->name, iname->len, oname->name);
+		oname->len = ret;
+		return ret;
+	}
+	if (hinfo) {
+		memcpy(buf, &hinfo->hash, 4);
+		memcpy(buf+4, &hinfo->minor_hash, 4);
+	} else
+		memset(buf, 0, 8);
+	memcpy(buf + 8, iname->name + iname->len - 16, 16);
+	oname->name[0] = '_';
+	ret = digest_encode(buf, 24, oname->name+1);
+	oname->len = ret + 1;
+	return ret + 1;
 }
 
 int ext4_fname_disk_to_usr(struct ext4_fname_crypto_ctx *ctx,
+			   struct dx_hash_info *hinfo,
 			   const struct ext4_dir_entry_2 *de,
 			   struct ext4_str *oname)
 {
 	struct ext4_str iname = {.name = (unsigned char *) de->name,
 				 .len = de->name_len };
 
-	return _ext4_fname_disk_to_usr(ctx, &iname, oname);
+	return _ext4_fname_disk_to_usr(ctx, hinfo, &iname, oname);
 }
 
 
@@ -640,10 +610,11 @@ int ext4_fname_usr_to_hash(struct ext4_fname_crypto_ctx *ctx,
 			    const struct qstr *iname,
 			    struct dx_hash_info *hinfo)
 {
-	struct ext4_str tmp, tmp2;
+	struct ext4_str tmp;
 	int ret = 0;
+	char buf[EXT4_FNAME_CRYPTO_DIGEST_SIZE+1];
 
-	if (!ctx || !ctx->has_valid_key ||
+	if (!ctx ||
 	    ((iname->name[0] == '.') &&
 	     ((iname->len == 1) ||
 	      ((iname->name[1] == '.') && (iname->len == 2))))) {
@@ -651,59 +622,90 @@ int ext4_fname_usr_to_hash(struct ext4_fname_crypto_ctx *ctx,
 		return 0;
 	}
 
+	if (!ctx->has_valid_key && iname->name[0] == '_') {
+		if (iname->len != 33)
+			return -ENOENT;
+		ret = digest_decode(iname->name+1, iname->len, buf);
+		if (ret != 24)
+			return -ENOENT;
+		memcpy(&hinfo->hash, buf, 4);
+		memcpy(&hinfo->minor_hash, buf + 4, 4);
+		return 0;
+	}
+
+	if (!ctx->has_valid_key && iname->name[0] != '_') {
+		if (iname->len > 43)
+			return -ENOENT;
+		ret = digest_decode(iname->name, iname->len, buf);
+		ext4fs_dirhash(buf, ret, hinfo);
+		return 0;
+	}
+
 	/* First encrypt the plaintext name */
 	ret = ext4_fname_crypto_alloc_buffer(ctx, iname->len, &tmp);
 	if (ret < 0)
 		return ret;
 
 	ret = ext4_fname_encrypt(ctx, iname, &tmp);
-	if (ret < 0)
-		goto out;
-
-	tmp2.len = (4 * ((EXT4_FNAME_CRYPTO_DIGEST_SIZE + 2) / 3)) + 1;
-	tmp2.name = kmalloc(tmp2.len + 1, GFP_KERNEL);
-	if (tmp2.name == NULL) {
-		ret = -ENOMEM;
-		goto out;
+	if (ret >= 0) {
+		ext4fs_dirhash(tmp.name, tmp.len, hinfo);
+		ret = 0;
 	}
 
-	ret = ext4_fname_hash(ctx, &tmp, &tmp2);
-	if (ret > 0)
-		ext4fs_dirhash(tmp2.name, tmp2.len, hinfo);
-	ext4_fname_crypto_free_buffer(&tmp2);
-out:
 	ext4_fname_crypto_free_buffer(&tmp);
 	return ret;
 }
 
-/**
- * ext4_fname_disk_to_htree() - converts a filename from disk space to htree-access string
- */
-int ext4_fname_disk_to_hash(struct ext4_fname_crypto_ctx *ctx,
-			    const struct ext4_dir_entry_2 *de,
-			    struct dx_hash_info *hinfo)
+int ext4_fname_match(struct ext4_fname_crypto_ctx *ctx, struct ext4_str *cstr,
+		     int len, const char * const name,
+		     struct ext4_dir_entry_2 *de)
 {
-	struct ext4_str iname = {.name = (unsigned char *) de->name,
-				 .len = de->name_len};
-	struct ext4_str tmp;
-	int ret;
+	int ret = -ENOENT;
+	int bigname = (*name == '_');
 
-	if (!ctx ||
-	    ((iname.name[0] == '.') &&
-	     ((iname.len == 1) ||
-	      ((iname.name[1] == '.') && (iname.len == 2))))) {
-		ext4fs_dirhash(iname.name, iname.len, hinfo);
-		return 0;
+	if (ctx->has_valid_key) {
+		if (cstr->name == NULL) {
+			struct qstr istr;
+
+			ret = ext4_fname_crypto_alloc_buffer(ctx, len, cstr);
+			if (ret < 0)
+				goto errout;
+			istr.name = name;
+			istr.len = len;
+			ret = ext4_fname_encrypt(ctx, &istr, cstr);
+			if (ret < 0)
+				goto errout;
+		}
+	} else {
+		if (cstr->name == NULL) {
+			cstr->name = kmalloc(32, GFP_KERNEL);
+			if (cstr->name == NULL)
+				return -ENOMEM;
+			if ((bigname && (len != 33)) ||
+			    (!bigname && (len > 43)))
+				goto errout;
+			ret = digest_decode(name+bigname, len-bigname,
+					    cstr->name);
+			if (ret < 0) {
+				ret = -ENOENT;
+				goto errout;
+			}
+			cstr->len = ret;
+		}
+		if (bigname) {
+			if (de->name_len < 16)
+				return 0;
+			ret = memcmp(de->name + de->name_len - 16,
+				     cstr->name + 8, 16);
+			return (ret == 0) ? 1 : 0;
+		}
 	}
-
-	tmp.len = (4 * ((EXT4_FNAME_CRYPTO_DIGEST_SIZE + 2) / 3)) + 1;
-	tmp.name = kmalloc(tmp.len + 1, GFP_KERNEL);
-	if (tmp.name == NULL)
-		return -ENOMEM;
-
-	ret = ext4_fname_hash(ctx, &iname, &tmp);
-	if (ret > 0)
-		ext4fs_dirhash(tmp.name, tmp.len, hinfo);
-	ext4_fname_crypto_free_buffer(&tmp);
+	if (de->name_len != cstr->len)
+		return 0;
+	ret = memcmp(de->name, cstr->name, cstr->len);
+	return (ret == 0) ? 1 : 0;
+errout:
+	kfree(cstr->name);
+	cstr->name = NULL;
 	return ret;
 }
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 61db51a5ce4c..5665d82d2332 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -249,7 +249,7 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
 				} else {
 					/* Directory is encrypted */
 					err = ext4_fname_disk_to_usr(enc_ctx,
-							de, &fname_crypto_str);
+						NULL, de, &fname_crypto_str);
 					if (err < 0)
 						goto errout;
 					if (!dir_emit(ctx,
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 0179654faf79..dfb113816672 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2093,9 +2093,11 @@ u32 ext4_fname_crypto_round_up(u32 size, u32 blksize);
 int ext4_fname_crypto_alloc_buffer(struct ext4_fname_crypto_ctx *ctx,
 				   u32 ilen, struct ext4_str *crypto_str);
 int _ext4_fname_disk_to_usr(struct ext4_fname_crypto_ctx *ctx,
+			    struct dx_hash_info *hinfo,
 			    const struct ext4_str *iname,
 			    struct ext4_str *oname);
 int ext4_fname_disk_to_usr(struct ext4_fname_crypto_ctx *ctx,
+			   struct dx_hash_info *hinfo,
 			   const struct ext4_dir_entry_2 *de,
 			   struct ext4_str *oname);
 int ext4_fname_usr_to_disk(struct ext4_fname_crypto_ctx *ctx,
@@ -2104,11 +2106,12 @@ int ext4_fname_usr_to_disk(struct ext4_fname_crypto_ctx *ctx,
 int ext4_fname_usr_to_hash(struct ext4_fname_crypto_ctx *ctx,
 			   const struct qstr *iname,
 			   struct dx_hash_info *hinfo);
-int ext4_fname_disk_to_hash(struct ext4_fname_crypto_ctx *ctx,
-			    const struct ext4_dir_entry_2 *de,
-			    struct dx_hash_info *hinfo);
 int ext4_fname_crypto_namelen_on_disk(struct ext4_fname_crypto_ctx *ctx,
 				      u32 namelen);
+int ext4_fname_match(struct ext4_fname_crypto_ctx *ctx, struct ext4_str *cstr,
+		     int len, const char * const name,
+		     struct ext4_dir_entry_2 *de);
+
 
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 void ext4_put_fname_crypto_ctx(struct ext4_fname_crypto_ctx **ctx);
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 4f87127f781f..5ea737114716 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -640,7 +640,7 @@ static struct stats dx_show_leaf(struct inode *dir,
 						ext4_put_fname_crypto_ctx(&ctx);
 						ctx = NULL;
 					}
-					res = ext4_fname_disk_to_usr(ctx, de,
+					res = ext4_fname_disk_to_usr(ctx, NULL, de,
 							&fname_crypto_str);
 					if (res < 0) {
 						printk(KERN_WARNING "Error "
@@ -653,15 +653,8 @@ static struct stats dx_show_leaf(struct inode *dir,
 						name = fname_crypto_str.name;
 						len = fname_crypto_str.len;
 					}
-					res = ext4_fname_disk_to_hash(ctx, de,
-								      &h);
-					if (res < 0) {
-						printk(KERN_WARNING "Error "
-							"converting filename "
-							"from disk to htree"
-							"\n");
-						h.hash = 0xDEADBEEF;
-					}
+					ext4fs_dirhash(de->name, de->name_len,
+						       &h);
 					printk("%*.s:(E)%x.%u ", len, name,
 					       h.hash, (unsigned) ((char *) de
 								   - base));
@@ -1008,15 +1001,7 @@ static int htree_dirblock_to_tree(struct file *dir_file,
 			/* silently ignore the rest of the block */
 			break;
 		}
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
-		err = ext4_fname_disk_to_hash(ctx, de, hinfo);
-		if (err < 0) {
-			count = err;
-			goto errout;
-		}
-#else
 		ext4fs_dirhash(de->name, de->name_len, hinfo);
-#endif
 		if ((hinfo->hash < start_hash) ||
 		    ((hinfo->hash == start_hash) &&
 		     (hinfo->minor_hash < start_minor_hash)))
@@ -1032,7 +1017,7 @@ static int htree_dirblock_to_tree(struct file *dir_file,
 				   &tmp_str);
 		} else {
 			/* Directory is encrypted */
-			err = ext4_fname_disk_to_usr(ctx, de,
+			err = ext4_fname_disk_to_usr(ctx, hinfo, de,
 						     &fname_crypto_str);
 			if (err < 0) {
 				count = err;
@@ -1193,26 +1178,10 @@ static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
 	int count = 0;
 	char *base = (char *) de;
 	struct dx_hash_info h = *hinfo;
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
-	struct ext4_fname_crypto_ctx *ctx = NULL;
-	int err;
-
-	ctx = ext4_get_fname_crypto_ctx(dir, EXT4_NAME_LEN);
-	if (IS_ERR(ctx))
-		return PTR_ERR(ctx);
-#endif
 
 	while ((char *) de < base + blocksize) {
 		if (de->name_len && de->inode) {
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
-			err = ext4_fname_disk_to_hash(ctx, de, &h);
-			if (err < 0) {
-				ext4_put_fname_crypto_ctx(&ctx);
-				return err;
-			}
-#else
 			ext4fs_dirhash(de->name, de->name_len, &h);
-#endif
 			map_tail--;
 			map_tail->hash = h.hash;
 			map_tail->offs = ((char *) de - base)>>2;
@@ -1223,9 +1192,6 @@ static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
 		/* XXX: do we need to check rec_len == 0 case? -Chris */
 		de = ext4_next_entry(de, blocksize);
 	}
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
-	ext4_put_fname_crypto_ctx(&ctx);
-#endif
 	return count;
 }
 
@@ -1287,16 +1253,8 @@ static inline int ext4_match(struct ext4_fname_crypto_ctx *ctx,
 		return 0;
 
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
-	if (ctx) {
-		/* Directory is encrypted */
-		res = ext4_fname_disk_to_usr(ctx, de, fname_crypto_str);
-		if (res < 0)
-			return res;
-		if (len != res)
-			return 0;
-		res = memcmp(name, fname_crypto_str->name, len);
-		return (res == 0) ? 1 : 0;
-	}
+	if (ctx)
+		return ext4_fname_match(ctx, fname_crypto_str, len, name, de);
 #endif
 	if (len != de->name_len)
 		return 0;
@@ -1324,16 +1282,6 @@ int search_dir(struct buffer_head *bh, char *search_buf, int buf_size,
 	if (IS_ERR(ctx))
 		return -1;
 
-	if (ctx != NULL) {
-		/* Allocate buffer to hold maximum name length */
-		res = ext4_fname_crypto_alloc_buffer(ctx, EXT4_NAME_LEN,
-						     &fname_crypto_str);
-		if (res < 0) {
-			ext4_put_fname_crypto_ctx(&ctx);
-			return -1;
-		}
-	}
-
 	de = (struct ext4_dir_entry_2 *)search_buf;
 	dlimit = search_buf + buf_size;
 	while ((char *) de < dlimit) {
@@ -1872,14 +1820,6 @@ int ext4_find_dest_de(struct inode *dir, struct inode *inode,
 			return res;
 		}
 		reclen = EXT4_DIR_REC_LEN(res);
-
-		/* Allocate buffer to hold maximum name length */
-		res = ext4_fname_crypto_alloc_buffer(ctx, EXT4_NAME_LEN,
-						     &fname_crypto_str);
-		if (res < 0) {
-			ext4_put_fname_crypto_ctx(&ctx);
-			return -1;
-		}
 	}
 
 	de = (struct ext4_dir_entry_2 *)buf;
diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
index 136ca0e911fd..ce2ed286ba08 100644
--- a/fs/ext4/symlink.c
+++ b/fs/ext4/symlink.c
@@ -74,7 +74,7 @@ static void *ext4_follow_link(struct dentry *dentry, struct nameidata *nd)
 		goto errout;
 	}
 	pstr.name = paddr;
-	res = _ext4_fname_disk_to_usr(ctx, &cstr, &pstr);
+	res = _ext4_fname_disk_to_usr(ctx, NULL, &cstr, &pstr);
 	if (res < 0)
 		goto errout;
 	/* Null-terminate the name */
-- 
cgit v1.2.3


From a44cd7a05496d60fd2ba8cca080e3db8f481549b Mon Sep 17 00:00:00 2001
From: Theodore Ts'o
Date: Fri, 1 May 2015 16:56:50 -0400
Subject: ext4 crypto: add padding to filenames before encrypting

This obscures the length of the filenames, to decrease the amount of
information leakage.  By default, we pad the filenames to the next 4
byte boundaries.  This costs nothing, since the directory entries are
aligned to 4 byte boundaries anyway.  Filenames can also be padded to
8, 16, or 32 bytes, which will consume more directory space.

Change-Id: Ibb7a0fb76d2c48e2061240a709358ff40b14f322
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/crypto_fname.c  | 12 ++++++++++--
 fs/ext4/crypto_key.c    |  1 +
 fs/ext4/crypto_policy.c | 14 +++++++++-----
 fs/ext4/ext4.h          |  1 +
 fs/ext4/ext4_crypto.h   | 11 ++++++++++-
 5 files changed, 31 insertions(+), 8 deletions(-)

(limited to 'fs/ext4')

diff --git a/fs/ext4/crypto_fname.c b/fs/ext4/crypto_fname.c
index 7a877e609e5f..fded02f72299 100644
--- a/fs/ext4/crypto_fname.c
+++ b/fs/ext4/crypto_fname.c
@@ -66,6 +66,7 @@ static int ext4_fname_encrypt(struct ext4_fname_crypto_ctx *ctx,
 	int res = 0;
 	char iv[EXT4_CRYPTO_BLOCK_SIZE];
 	struct scatterlist sg[1];
+	int padding = 4 << (ctx->flags & EXT4_POLICY_FLAGS_PAD_MASK);
 	char *workbuf;
 
 	if (iname->len <= 0 || iname->len > ctx->lim)
@@ -73,6 +74,7 @@ static int ext4_fname_encrypt(struct ext4_fname_crypto_ctx *ctx,
 
 	ciphertext_len = (iname->len < EXT4_CRYPTO_BLOCK_SIZE) ?
 		EXT4_CRYPTO_BLOCK_SIZE : iname->len;
+	ciphertext_len = ext4_fname_crypto_round_up(ciphertext_len, padding);
 	ciphertext_len = (ciphertext_len > ctx->lim)
 			? ctx->lim : ciphertext_len;
 
@@ -101,7 +103,7 @@ static int ext4_fname_encrypt(struct ext4_fname_crypto_ctx *ctx,
 	/* Create encryption request */
 	sg_init_table(sg, 1);
 	sg_set_page(sg, ctx->workpage, PAGE_SIZE, 0);
-	ablkcipher_request_set_crypt(req, sg, sg, iname->len, iv);
+	ablkcipher_request_set_crypt(req, sg, sg, ciphertext_len, iv);
 	res = crypto_ablkcipher_encrypt(req);
 	if (res == -EINPROGRESS || res == -EBUSY) {
 		BUG_ON(req->base.data != &ecr);
@@ -356,6 +358,7 @@ struct ext4_fname_crypto_ctx *ext4_get_fname_crypto_ctx(
 	if (IS_ERR(ctx))
 		return ctx;
 
+	ctx->flags = ei->i_crypt_policy_flags;
 	if (ctx->has_valid_key) {
 		if (ctx->key.mode != EXT4_ENCRYPTION_MODE_AES_256_CTS) {
 			printk_once(KERN_WARNING
@@ -468,6 +471,7 @@ int ext4_fname_crypto_namelen_on_disk(struct ext4_fname_crypto_ctx *ctx,
 				      u32 namelen)
 {
 	u32 ciphertext_len;
+	int padding = 4 << (ctx->flags & EXT4_POLICY_FLAGS_PAD_MASK);
 
 	if (ctx == NULL)
 		return -EIO;
@@ -475,6 +479,7 @@ int ext4_fname_crypto_namelen_on_disk(struct ext4_fname_crypto_ctx *ctx,
 		return -EACCES;
 	ciphertext_len = (namelen < EXT4_CRYPTO_BLOCK_SIZE) ?
 		EXT4_CRYPTO_BLOCK_SIZE : namelen;
+	ciphertext_len = ext4_fname_crypto_round_up(ciphertext_len, padding);
 	ciphertext_len = (ciphertext_len > ctx->lim)
 			? ctx->lim : ciphertext_len;
 	return (int) ciphertext_len;
@@ -490,10 +495,13 @@ int ext4_fname_crypto_alloc_buffer(struct ext4_fname_crypto_ctx *ctx,
 				   u32 ilen, struct ext4_str *crypto_str)
 {
 	unsigned int olen;
+	int padding = 4 << (ctx->flags & EXT4_POLICY_FLAGS_PAD_MASK);
 
 	if (!ctx)
 		return -EIO;
-	olen = ext4_fname_crypto_round_up(ilen, EXT4_CRYPTO_BLOCK_SIZE);
+	if (padding < EXT4_CRYPTO_BLOCK_SIZE)
+		padding = EXT4_CRYPTO_BLOCK_SIZE;
+	olen = ext4_fname_crypto_round_up(ilen, padding);
 	crypto_str->len = olen;
 	if (olen < EXT4_FNAME_CRYPTO_DIGEST_SIZE*2)
 		olen = EXT4_FNAME_CRYPTO_DIGEST_SIZE*2;
diff --git a/fs/ext4/crypto_key.c b/fs/ext4/crypto_key.c
index c8392af8abbb..52170d0b7c40 100644
--- a/fs/ext4/crypto_key.c
+++ b/fs/ext4/crypto_key.c
@@ -110,6 +110,7 @@ int ext4_generate_encryption_key(struct inode *inode)
 	}
 	res = 0;
 
+	ei->i_crypt_policy_flags = ctx.flags;
 	if (S_ISREG(inode->i_mode))
 		crypt_key->mode = ctx.contents_encryption_mode;
 	else if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
diff --git a/fs/ext4/crypto_policy.c b/fs/ext4/crypto_policy.c
index 30eaf9e9864a..a6d6291aea16 100644
--- a/fs/ext4/crypto_policy.c
+++ b/fs/ext4/crypto_policy.c
@@ -37,6 +37,8 @@ static int ext4_is_encryption_context_consistent_with_policy(
 		return 0;
 	return (memcmp(ctx.master_key_descriptor, policy->master_key_descriptor,
 			EXT4_KEY_DESCRIPTOR_SIZE) == 0 &&
+		(ctx.flags ==
+		 policy->flags) &&
 		(ctx.contents_encryption_mode ==
 		 policy->contents_encryption_mode) &&
 		(ctx.filenames_encryption_mode ==
@@ -56,25 +58,25 @@ static int ext4_create_encryption_context_from_policy(
 		printk(KERN_WARNING
 		       "%s: Invalid contents encryption mode %d\n", __func__,
 			policy->contents_encryption_mode);
-		res = -EINVAL;
-		goto out;
+		return -EINVAL;
 	}
 	if (!ext4_valid_filenames_enc_mode(policy->filenames_encryption_mode)) {
 		printk(KERN_WARNING
 		       "%s: Invalid filenames encryption mode %d\n", __func__,
 			policy->filenames_encryption_mode);
-		res = -EINVAL;
-		goto out;
+		return -EINVAL;
 	}
+	if (policy->flags & ~EXT4_POLICY_FLAGS_VALID)
+		return -EINVAL;
 	ctx.contents_encryption_mode = policy->contents_encryption_mode;
 	ctx.filenames_encryption_mode = policy->filenames_encryption_mode;
+	ctx.flags = policy->flags;
 	BUILD_BUG_ON(sizeof(ctx.nonce) != EXT4_KEY_DERIVATION_NONCE_SIZE);
 	get_random_bytes(ctx.nonce, EXT4_KEY_DERIVATION_NONCE_SIZE);
 
 	res = ext4_xattr_set(inode, EXT4_XATTR_INDEX_ENCRYPTION,
 			     EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, &ctx,
 			     sizeof(ctx), 0);
-out:
 	if (!res)
 		ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
 	return res;
@@ -115,6 +117,7 @@ int ext4_get_policy(struct inode *inode, struct ext4_encryption_policy *policy)
 	policy->version = 0;
 	policy->contents_encryption_mode = ctx.contents_encryption_mode;
 	policy->filenames_encryption_mode = ctx.filenames_encryption_mode;
+	policy->flags = ctx.flags;
 	memcpy(&policy->master_key_descriptor, ctx.master_key_descriptor,
 	       EXT4_KEY_DESCRIPTOR_SIZE);
 	return 0;
@@ -176,6 +179,7 @@ int ext4_inherit_context(struct inode *parent, struct inode *child)
 				EXT4_ENCRYPTION_MODE_AES_256_XTS;
 			ctx.filenames_encryption_mode =
 				EXT4_ENCRYPTION_MODE_AES_256_CTS;
+			ctx.flags = 0;
 			memset(ctx.master_key_descriptor, 0x42,
 			       EXT4_KEY_DESCRIPTOR_SIZE);
 			res = 0;
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index dfb113816672..bca1bdc67725 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -911,6 +911,7 @@ struct ext4_inode_info {
 
 	/* on-disk additional length */
 	__u16 i_extra_isize;
+	char i_crypt_policy_flags;
 
 	/* Indicate the inline data space. */
 	u16 i_inline_off;
diff --git a/fs/ext4/ext4_crypto.h b/fs/ext4/ext4_crypto.h
index c2ba35a914b6..d75159c101ce 100644
--- a/fs/ext4/ext4_crypto.h
+++ b/fs/ext4/ext4_crypto.h
@@ -20,12 +20,20 @@ struct ext4_encryption_policy {
 	char version;
 	char contents_encryption_mode;
 	char filenames_encryption_mode;
+	char flags;
 	char master_key_descriptor[EXT4_KEY_DESCRIPTOR_SIZE];
 } __attribute__((__packed__));
 
 #define EXT4_ENCRYPTION_CONTEXT_FORMAT_V1 1
 #define EXT4_KEY_DERIVATION_NONCE_SIZE 16
 
+#define EXT4_POLICY_FLAGS_PAD_4		0x00
+#define EXT4_POLICY_FLAGS_PAD_8		0x01
+#define EXT4_POLICY_FLAGS_PAD_16	0x02
+#define EXT4_POLICY_FLAGS_PAD_32	0x03
+#define EXT4_POLICY_FLAGS_PAD_MASK	0x03
+#define EXT4_POLICY_FLAGS_VALID		0x03
+
 /**
  * Encryption context for inode
  *
@@ -41,7 +49,7 @@ struct ext4_encryption_context {
 	char format;
 	char contents_encryption_mode;
 	char filenames_encryption_mode;
-	char reserved;
+	char flags;
 	char master_key_descriptor[EXT4_KEY_DESCRIPTOR_SIZE];
 	char nonce[EXT4_KEY_DERIVATION_NONCE_SIZE];
 } __attribute__((__packed__));
@@ -120,6 +128,7 @@ struct ext4_fname_crypto_ctx {
 	struct crypto_hash *htfm;
 	struct page *workpage;
 	struct ext4_encryption_key key;
+	unsigned flags : 8;
 	unsigned has_valid_key : 1;
 	unsigned ctfm_key_is_ready : 1;
 };
-- 
cgit v1.2.3


From fb63e5489f7ef5bb4d1a655984ca7ef98ffc5849 Mon Sep 17 00:00:00 2001
From: Herbert Xu
Date: Sat, 2 May 2015 10:29:19 -0400
Subject: ext4 crypto: do not select from EXT4_FS_ENCRYPTION

This patch adds a tristate EXT4_ENCRYPTION to do the selections
for EXT4_FS_ENCRYPTION because selecting from a bool causes all
the selected options to be built-in, even if EXT4 itself is a
module.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/Kconfig | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

(limited to 'fs/ext4')

diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig
index 18228c201f7f..024f2284d3f6 100644
--- a/fs/ext4/Kconfig
+++ b/fs/ext4/Kconfig
@@ -64,8 +64,8 @@ config EXT4_FS_SECURITY
 	  If you are not using a security module that requires using
 	  extended attributes for file security labels, say N.
 
-config EXT4_FS_ENCRYPTION
-	bool "Ext4 Encryption"
+config EXT4_ENCRYPTION
+	tristate "Ext4 Encryption"
 	depends on EXT4_FS
 	select CRYPTO_AES
 	select CRYPTO_CBC
@@ -81,6 +81,11 @@ config EXT4_FS_ENCRYPTION
 	  efficient since it avoids caching the encrypted and
 	  decrypted pages in the page cache.
 
+config EXT4_FS_ENCRYPTION
+	bool
+	default y
+	depends on EXT4_ENCRYPTION
+
 config EXT4_DEBUG
 	bool "EXT4 debugging support"
 	depends on EXT4_FS
-- 
cgit v1.2.3


From 9402bdcacdfedf7219a17e4d93300058a8e2aa4c Mon Sep 17 00:00:00 2001
From: Chanho Park
Date: Sat, 2 May 2015 10:29:22 -0400
Subject: ext4 crypto: remove duplicated encryption mode definitions

This patch removes duplicated encryption modes which were already in
ext4.h. They were duplicated from commit 3edc18d and commit f542fb.

Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Michael Halcrow <mhalcrow@google.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Signed-off-by: Chanho Park <chanho61.park@samsung.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/ext4.h | 6 ------
 1 file changed, 6 deletions(-)

(limited to 'fs/ext4')

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index bca1bdc67725..1de8c7f06897 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1067,12 +1067,6 @@ extern void ext4_set_bits(void *bm, int cur, int len);
 /* Metadata checksum algorithm codes */
 #define EXT4_CRC32C_CHKSUM		1
 
-/* Encryption algorithms */
-#define EXT4_ENCRYPTION_MODE_INVALID		0
-#define EXT4_ENCRYPTION_MODE_AES_256_XTS	1
-#define EXT4_ENCRYPTION_MODE_AES_256_GCM	2
-#define EXT4_ENCRYPTION_MODE_AES_256_CBC	3
-
 /*
  * Structure of the super block
  */
-- 
cgit v1.2.3


From d2dc317d564a46dfc683978a2e5a4f91434e9711 Mon Sep 17 00:00:00 2001
From: Lukas Czerner
Date: Sat, 2 May 2015 21:36:55 -0400
Subject: ext4: fix data corruption caused by unwritten and delayed extents

Currently it is possible to lose whole file system block worth of data
when we hit the specific interaction with unwritten and delayed extents
in status extent tree.

The problem is that when we insert delayed extent into extent status
tree the only way to get rid of it is when we write out delayed buffer.
However there is a limitation in the extent status tree implementation
so that when inserting unwritten extent should there be even a single
delayed block the whole unwritten extent would be marked as delayed.

At this point, there is no way to get rid of the delayed extents,
because there are no delayed buffers to write out. So when a we write
into said unwritten extent we will convert it to written, but it still
remains delayed.

When we try to write into that block later ext4_da_map_blocks() will set
the buffer new and delayed and map it to invalid block which causes
the rest of the block to be zeroed loosing already written data.

For now we can fix this by simply not allowing to set delayed status on
written extent in the extent status tree. Also add WARN_ON() to make
sure that we notice if this happens in the future.

This problem can be easily reproduced by running the following xfs_io.

xfs_io -f -c "pwrite -S 0xaa 4096 2048" \
          -c "falloc 0 131072" \
          -c "pwrite -S 0xbb 65536 2048" \
          -c "fsync" /mnt/test/fff

echo 3 > /proc/sys/vm/drop_caches
xfs_io -c "pwrite -S 0xdd 67584 2048" /mnt/test/fff

This can be theoretically also reproduced by at random by running fsx,
but it's not very reliable, though on machines with bigger page size
(like ppc) this can be seen more often (especially xfstest generic/127)

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
---
 fs/ext4/extents_status.c | 8 ++++++++
 fs/ext4/inode.c          | 2 ++
 2 files changed, 10 insertions(+)

(limited to 'fs/ext4')

diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index d33d5a6852b9..26724aeece73 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -703,6 +703,14 @@ int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
 
 	BUG_ON(end < lblk);
 
+	if ((status & EXTENT_STATUS_DELAYED) &&
+	    (status & EXTENT_STATUS_WRITTEN)) {
+		ext4_warning(inode->i_sb, "Inserting extent [%u/%u] as "
+				" delayed and written which can potentially "
+				" cause data loss.\n", lblk, len);
+		WARN_ON(1);
+	}
+
 	newes.es_lblk = lblk;
 	newes.es_len = len;
 	ext4_es_store_pblock_status(&newes, pblk, status);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index f6b35d8a4a5b..4415cea85ced 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -532,6 +532,7 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
 		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
 				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
 		if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
+		    !(status & EXTENT_STATUS_WRITTEN) &&
 		    ext4_find_delalloc_range(inode, map->m_lblk,
 					     map->m_lblk + map->m_len - 1))
 			status |= EXTENT_STATUS_DELAYED;
@@ -636,6 +637,7 @@ found:
 		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
 				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
 		if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
+		    !(status & EXTENT_STATUS_WRITTEN) &&
 		    ext4_find_delalloc_range(inode, map->m_lblk,
 					     map->m_lblk + map->m_len - 1))
 			status |= EXTENT_STATUS_DELAYED;
-- 
cgit v1.2.3


From 280227a75b56ab5d35854f3a77ef74a7ad56a203 Mon Sep 17 00:00:00 2001
From: Davide Italiano
Date: Sat, 2 May 2015 23:21:15 -0400
Subject: ext4: move check under lock scope to close a race.

fallocate() checks that the file is extent-based and returns
EOPNOTSUPP in case is not. Other tasks can convert from and to
indirect and extent so it's safe to check only after grabbing
the inode mutex.

Signed-off-by: Davide Italiano <dccitaliano@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
---
 fs/ext4/extents.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

(limited to 'fs/ext4')

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 973816bfe4a9..d74e08029643 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4927,13 +4927,6 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 	if (ret)
 		return ret;
 
-	/*
-	 * currently supporting (pre)allocate mode for extent-based
-	 * files _only_
-	 */
-	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
-		return -EOPNOTSUPP;
-
 	if (mode & FALLOC_FL_COLLAPSE_RANGE)
 		return ext4_collapse_range(inode, offset, len);
 
@@ -4955,6 +4948,14 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 
 	mutex_lock(&inode->i_mutex);
 
+	/*
+	 * We only support preallocation for extent-based files only
+	 */
+	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
+
 	if (!(mode & FALLOC_FL_KEEP_SIZE) &&
 	     offset + len > i_size_read(inode)) {
 		new_size = offset + len;
-- 
cgit v1.2.3


From 2c869b262a10ca99cb866d04087d75311587a30c Mon Sep 17 00:00:00 2001
From: Jan Kara
Date: Sat, 2 May 2015 23:58:32 -0400
Subject: ext4: fix growing of tiny filesystems

The estimate of necessary transaction credits in ext4_flex_group_add()
is too pessimistic. It reserves credit for sb, resize inode, and resize
inode dindirect block for each group added in a flex group although they
are always the same block and thus it is enough to account them only
once. Also the number of modified GDT block is overestimated since we
fit EXT4_DESC_PER_BLOCK(sb) descriptors in one block.

Make the estimation more precise. That reduces number of requested
credits enough that we can grow 20 MB filesystem (which has 1 MB
journal, 79 reserved GDT blocks, and flex group size 16 by default).

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
---
 fs/ext4/resize.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

(limited to 'fs/ext4')

diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 8a8ec6293b19..cf0c472047e3 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1432,12 +1432,15 @@ static int ext4_flex_group_add(struct super_block *sb,
 		goto exit;
 	/*
 	 * We will always be modifying at least the superblock and  GDT
-	 * block.  If we are adding a group past the last current GDT block,
+	 * blocks.  If we are adding a group past the last current GDT block,
 	 * we will also modify the inode and the dindirect block.  If we
 	 * are adding a group with superblock/GDT backups  we will also
 	 * modify each of the reserved GDT dindirect blocks.
 	 */
-	credit = flex_gd->count * 4 + reserved_gdb;
+	credit = 3;	/* sb, resize inode, resize inode dindirect */
+	/* GDT blocks */
+	credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
+	credit += reserved_gdb;	/* Reserved GDT dindirect blocks */
 	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
 	if (IS_ERR(handle)) {
 		err = PTR_ERR(handle);
-- 
cgit v1.2.3