Heinrich,
On Sun, May 12, 2019 at 09:59:18AM +0200, Heinrich Schuchardt wrote:
> File names may not contain control characters (< 0x20).
> Simplify the coding.
>
> Signed-off-by: Heinrich Schuchardt <xypron.g...@gmx.de>
> ---
> fs/fat/fat_write.c | 48 +++++++++++++++++++---------------------------
> 1 file changed, 20 insertions(+), 28 deletions(-)
>
> diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c
> index 852f874e58..2a74199236 100644
> --- a/fs/fat/fat_write.c
> +++ b/fs/fat/fat_write.c
> @@ -1009,40 +1009,32 @@ again:
> return 0;
> }
>
> +/**
> + * normalize_longname() - check long file name and convert to lower case
> + *
> + * We assume here that the FAT file system is using an 8bit code page.
> + * Linux typically uses CP437, EDK2 assumes CP1250.
> + *
> + * @l_filename: preallocated buffer receiving the normalized name
> + * @filename: filename to normalize
> + * Return: 0 on success, -1 on failure
> + */
> static int normalize_longname(char *l_filename, const char *filename)
> {
> - const char *p, legal[] = "!#$%&\'()-.@^`_{}~";
> - unsigned char c;
> - int name_len;
> -
> - /* Check that the filename is valid */
> - for (p = filename; p < filename + strlen(filename); p++) {
> - c = *p;
> -
> - if (('0' <= c) && (c <= '9'))
> - continue;
> - if (('A' <= c) && (c <= 'Z'))
> - continue;
> - if (('a' <= c) && (c <= 'z'))
> - continue;
> - if (strchr(legal, c))
> - continue;
> - /* extended code */
> - if ((0x80 <= c) && (c <= 0xff))
> - continue;
> + const char *p, illegal[] = "<>:\"/\\|?*";
With your patch, 8 characters, " +,;-[]" and \177 (= DEL), are
added as legal characters. DEL should be excluded.
Other than that, the rule seems to be fine for long file names.
> + if (strlen(filename) >= VFAT_MAXLEN_BYTES)
> return -1;
> - }
>
> - /* Normalize it */
> - name_len = strlen(filename);
> - if (name_len >= VFAT_MAXLEN_BYTES)
> - /* should return an error? */
> - name_len = VFAT_MAXLEN_BYTES - 1;
> + for (p = filename; *p; ++p) {
> + if ((unsigned char)*p < 0x20)
> + return -1;
> + if (strchr(illegal, *p))
> + return -1;
> + }
>
> - memcpy(l_filename, filename, name_len);
> - l_filename[name_len] = 0; /* terminate the string */
> - downcase(l_filename, INT_MAX);
> + strcpy(l_filename, filename);
> + downcase(l_filename, VFAT_MAXLEN_BYTES);
Strictly speaking,
it is not necessary to 'downcase' a file name here as a long file
name may contain lower-case characters.
On the other hand, a short file name, which is to be set in
set_name(), should be checked against more restricted character set.
In addition,
l_filename, instead of filename, should be passed to fill_dir_slot()
at file_fat_write_at() as fill_dir_slot() expects a long file name.
l_dirname in fat_mkdir() as well.
-Takahiro Akashi
> return 0;
> }
> --
> 2.20.1
>
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