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Date: Thu, 10 Dec 2020 17:51:26 -0300
From: Gabriel Krisman Bertazi <krisman@...labora.com>
To: Arnaud Ferraris <arnaud.ferraris@...labora.com>
Cc: linux-ext4@...r.kernel.org, drosen@...gle.com, ebiggers@...nel.org,
tytso@....edu
Subject: Re: [PATCH RESEND v2 06/12] e2fsck: Fix entries with invalid
encoded characters
Arnaud Ferraris <arnaud.ferraris@...labora.com> writes:
> 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++;
> }
This won't do for encrypted+casefolded directories, right?
>
> if (dx_db) {
--
Gabriel Krisman Bertazi
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