From: AKASHI Takahiro <takahiro.aka...@linaro.org>
FAT file system's long file name support is a bit complicated and has some
restrictions on its naming. We should be careful about it especially for
write as it may easily end up with wrong file system.
normalize_longname() check for the rules and normalize a file name
if necessary. Please note, however, that this function is yet to be
extended to fully comply with the standard.
Signed-off-by: AKASHI Takahiro <takahiro.aka...@linaro.org>
---
fs/fat/fat_write.c | 52 +++++++++++++++++++++++++++++++++++++++-------
1 file changed, 44 insertions(+), 8 deletions(-)
diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c
index 3b77557b3ede..6c715a70f447 100644
--- a/fs/fat/fat_write.c
+++ b/fs/fat/fat_write.c
@@ -899,6 +899,44 @@ static dir_entry *find_directory_entry(fsdata *mydata, int
startsect,
return NULL;
}
+static int normalize_longname(char *l_filename, const char *filename)
+{
+ const char *p, legal[] = "!#$%&\'()-.@^`_{}~";
+ 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;
+
+ return -1;
+ }
+
+ /* Normalize it */
+ name_len = strlen(filename);
+ if (name_len >= VFAT_MAXLEN_BYTES)
+ /* should return an error? */
+ name_len = VFAT_MAXLEN_BYTES - 1;
+
+ memcpy(l_filename, filename, name_len);
+ l_filename[name_len] = 0; /* terminate the string */
+ downcase(l_filename, INT_MAX);
+
+ return 0;
+}
+
static int do_fat_write(const char *filename, void *buffer, loff_t size,
loff_t *actwrite)
{
@@ -910,7 +948,7 @@ static int do_fat_write(const char *filename, void *buffer,
loff_t size,
fsdata datablock;
fsdata *mydata = &datablock;
int cursect;
- int ret = -1, name_len;
+ int ret = -1;
char l_filename[VFAT_MAXLEN_BYTES];
*actwrite = size;
@@ -971,13 +1009,11 @@ static int do_fat_write(const char *filename, void
*buffer, loff_t size,
}
dentptr = (dir_entry *) do_fat_read_at_block;
- name_len = strlen(filename);
- if (name_len >= VFAT_MAXLEN_BYTES)
- name_len = VFAT_MAXLEN_BYTES - 1;
-
- memcpy(l_filename, filename, name_len);
- l_filename[name_len] = 0; /* terminate the string */
- downcase(l_filename, INT_MAX);
+ if (normalize_longname(l_filename, filename)) {
+ printf("FAT: illegal filename (%s)\n", filename);
+ ret = -EINVAL;
+ goto exit;
+ }
startsect = mydata->rootdir_sect;
retdent = find_directory_entry(mydata, startsect,
--
2.18.0
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