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Date:   Fri, 27 Nov 2020 18:01:10 +0100
From:   Arnaud Ferraris <arnaud.ferraris@...labora.com>
To:     linux-ext4@...r.kernel.org
Cc:     Daniel Rosenberg <drosen@...gle.com>,
        Gabriel Krisman Bertazi <krisman@...labora.com>,
        Arnaud Ferraris <arnaud.ferraris@...labora.com>
Subject: [PATCH v2 06/12] e2fsck: Fix entries with invalid encoded characters

From: Gabriel Krisman Bertazi <krisman@...labora.com>

On strict mode, invalid Unicode sequences are not permited.  This patch
adds a verification step to pass2 to detect and modify the entries with
the same replacement char used for non-encoding directories '.'.

After the encoding test, we still want to check the name for usual
problems, '\0', '/' in the middle of the sequence.

Signed-off-by: Gabriel Krisman Bertazi <krisman@...labora.com>
Signed-off-by: Arnaud Ferraris <arnaud.ferraris@...labora.com>
---
Changes in v2:
  - added missing comment
  - uses the problem code introduced by the previous patch
  - reworked a test to ease future support of encrypted+casefolded
    directories

 e2fsck/e2fsck.c |  4 ++++
 e2fsck/e2fsck.h |  1 +
 e2fsck/pass1.c  | 18 +++++++++++++++++
 e2fsck/pass2.c  | 51 ++++++++++++++++++++++++++++++++++++++++++++-----
 4 files changed, 69 insertions(+), 5 deletions(-)

diff --git a/e2fsck/e2fsck.c b/e2fsck/e2fsck.c
index d8be566f..dc4b45e2 100644
--- a/e2fsck/e2fsck.c
+++ b/e2fsck/e2fsck.c
@@ -75,6 +75,10 @@ errcode_t e2fsck_reset_context(e2fsck_t ctx)
 		ext2fs_free_block_bitmap(ctx->block_found_map);
 		ctx->block_found_map = 0;
 	}
+	if (ctx->inode_casefold_map) {
+		ext2fs_free_block_bitmap(ctx->inode_casefold_map);
+		ctx->inode_casefold_map = 0;
+	}
 	if (ctx->inode_link_info) {
 		ext2fs_free_icount(ctx->inode_link_info);
 		ctx->inode_link_info = 0;
diff --git a/e2fsck/e2fsck.h b/e2fsck/e2fsck.h
index 85f953b2..dcaab0a1 100644
--- a/e2fsck/e2fsck.h
+++ b/e2fsck/e2fsck.h
@@ -262,6 +262,7 @@ struct e2fsck_struct {
 	ext2fs_inode_bitmap inode_bb_map; /* Inodes which are in bad blocks */
 	ext2fs_inode_bitmap inode_imagic_map; /* AFS inodes */
 	ext2fs_inode_bitmap inode_reg_map; /* Inodes which are regular files*/
+	ext2fs_inode_bitmap inode_casefold_map; /* Inodes which are casefolded */
 
 	ext2fs_block_bitmap block_found_map; /* Blocks which are in use */
 	ext2fs_block_bitmap block_dup_map; /* Blks referenced more than once */
diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
index 8eecd958..6909fed5 100644
--- a/e2fsck/pass1.c
+++ b/e2fsck/pass1.c
@@ -23,6 +23,7 @@
  * 	- A bitmap of which inodes have bad fields.	(inode_bad_map)
  * 	- A bitmap of which inodes are in bad blocks.	(inode_bb_map)
  * 	- A bitmap of which inodes are imagic inodes.	(inode_imagic_map)
+ * 	- A bitmap of which inodes are casefolded.	(inode_casefold_map)
  * 	- A bitmap of which blocks are in use.		(block_found_map)
  * 	- A bitmap of which blocks are in use by two inodes	(block_dup_map)
  * 	- The data blocks of the directory inodes.	(dir_map)
@@ -1260,6 +1261,20 @@ void e2fsck_pass1(e2fsck_t ctx)
 		ctx->flags |= E2F_FLAG_ABORT;
 		return;
 	}
+	if (casefold_fs) {
+		pctx.errcode =
+			e2fsck_allocate_inode_bitmap(fs,
+						     _("inode casefold map"),
+						     EXT2FS_BMAP64_RBTREE,
+						     "inode_casefold_map",
+						     &ctx->inode_casefold_map);
+		if (pctx.errcode) {
+			pctx.num = 1;
+			fix_problem(ctx, PR_1_ALLOCATE_IBITMAP_ERROR, &pctx);
+			ctx->flags |= E2F_FLAG_ABORT;
+			return;
+		}
+	}
 	pctx.errcode = e2fsck_setup_icount(ctx, "inode_link_info", 0, NULL,
 					   &ctx->inode_link_info);
 	if (pctx.errcode) {
@@ -1870,6 +1885,9 @@ void e2fsck_pass1(e2fsck_t ctx)
 		    add_encrypted_file(ctx, &pctx) < 0)
 			goto clear_inode;
 
+		if (casefold_fs && inode->i_flags & EXT4_CASEFOLD_FL)
+			ext2fs_mark_inode_bitmap2(ctx->inode_casefold_map, ino);
+
 		if (LINUX_S_ISDIR(inode->i_mode)) {
 			ext2fs_mark_inode_bitmap2(ctx->inode_dir_map, ino);
 			e2fsck_add_dir_info(ctx, ino, 0);
diff --git a/e2fsck/pass2.c b/e2fsck/pass2.c
index 4dbc44ea..b9402b24 100644
--- a/e2fsck/pass2.c
+++ b/e2fsck/pass2.c
@@ -36,11 +36,13 @@
  * 	- The inode_bad_map bitmap
  * 	- The inode_dir_map bitmap
  * 	- The encrypted_file_info
+ *	- The inode_casefold_map bitmap
  *
  * Pass 2 frees the following data structures
  * 	- The inode_bad_map bitmap
  * 	- The inode_reg_map bitmap
  * 	- The encrypted_file_info
+ *	- The inode_casefold_map bitmap
  */
 
 #define _GNU_SOURCE 1 /* get strnlen() */
@@ -287,6 +289,10 @@ void e2fsck_pass2(e2fsck_t ctx)
 		ext2fs_free_inode_bitmap(ctx->inode_reg_map);
 		ctx->inode_reg_map = 0;
 	}
+	if (ctx->inode_casefold_map) {
+		ext2fs_free_inode_bitmap(ctx->inode_casefold_map);
+		ctx->inode_casefold_map = 0;
+	}
 	destroy_encrypted_file_info(ctx);
 
 	clear_problem_context(&pctx);
@@ -515,6 +521,30 @@ static int encrypted_check_name(e2fsck_t ctx,
 	return 0;
 }
 
+static int encoded_check_name(e2fsck_t ctx,
+			      struct ext2_dir_entry *dirent,
+			      struct problem_context *pctx)
+{
+	const struct ext2fs_nls_table *tbl = ctx->fs->encoding;
+	int ret;
+	int len = ext2fs_dirent_name_len(dirent);
+	char *pos, *end;
+
+	ret = ext2fs_check_encoded_name(tbl, dirent->name, len, &pos);
+	if (ret < 0) {
+		fatal_error(ctx, _("NLS is broken."));
+	} else if(ret > 0) {
+		ret = fix_problem(ctx, PR_2_BAD_CASEFOLDED_NAME, pctx);
+		if (ret) {
+			end = &dirent->name[len];
+			for (; *pos && pos != end; pos++)
+				*pos = '.';
+		}
+	}
+
+	return (ret || check_name(ctx, dirent, pctx));
+}
+
 /*
  * Check the directory filetype (if present)
  */
@@ -998,11 +1028,18 @@ static int check_dir_block(ext2_filsys fs,
 	size_t	max_block_size;
 	int	hash_flags = 0;
 	static char *eop_read_dirblock = NULL;
+	int cf_dir = 0;
 
 	cd = (struct check_dir_struct *) priv_data;
 	ibuf = buf = cd->buf;
 	ctx = cd->ctx;
 
+	/* We only want filename encoding verification on strict
+	 * mode. */
+	if (ext2fs_test_inode_bitmap2(ctx->inode_casefold_map, ino) &&
+	    (ctx->fs->super->s_encoding_flags & EXT4_ENC_STRICT_MODE_FL))
+		cf_dir = 1;
+
 	if (ctx->flags & E2F_FLAG_RUN_RETURN)
 		return DIRENT_ABORT;
 
@@ -1483,11 +1520,7 @@ skip_checksum:
 		if (check_filetype(ctx, dirent, ino, &cd->pctx))
 			dir_modified++;
 
-		if (dir_encpolicy_id == NO_ENCRYPTION_POLICY) {
-			/* Unencrypted directory */
-			if (check_name(ctx, dirent, &cd->pctx))
-				dir_modified++;
-		} else {
+		if (dir_encpolicy_id != NO_ENCRYPTION_POLICY) {
 			/* Encrypted directory */
 			if (dot_state > 1 &&
 			    check_encrypted_dirent(ctx, dirent,
@@ -1497,6 +1530,14 @@ skip_checksum:
 				dir_modified++;
 				goto next;
 			}
+		} else if (cf_dir) {
+			/* Casefolded directory */
+			if (encoded_check_name(ctx, dirent, &cd->pctx))
+				dir_modified++;
+		} else {
+			/* Unencrypted and uncasefolded directory */
+			if (check_name(ctx, dirent, &cd->pctx))
+				dir_modified++;
 		}
 
 		if (dx_db) {
-- 
2.28.0

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