From 0dc1bfb7302d220a48364263d5632d6d572b069b Mon Sep 17 00:00:00 2001 From: Heinrich Schuchardt Date: Mon, 2 Jul 2018 02:41:23 +0200 Subject: [PATCH] fs: fat: cannot write to subdirectories fs_fat_write() is not able to write to subdirectories. Currently if a filepath with a leading slash is passed, the slash is treated as part of the filename to be created in the root directory. Strip leading (back-)slashes. Check that the remaining filename does not contain any illegal characters (<>:"/\|?*). This way we will throw an error when trying to write to a subdirectory. Signed-off-by: Heinrich Schuchardt Signed-off-by: Alexander Graf --- fs/fat/fat_write.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c index 3b77557..27e0ff6 100644 --- a/fs/fat/fat_write.c +++ b/fs/fat/fat_write.c @@ -909,9 +909,11 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size, volume_info volinfo; fsdata datablock; fsdata *mydata = &datablock; - int cursect; + int cursect, i; int ret = -1, name_len; char l_filename[VFAT_MAXLEN_BYTES]; + char bad[2] = " "; + const char illegal[] = "<>:\"/\\|?*"; *actwrite = size; dir_curclust = 0; @@ -971,6 +973,18 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size, } dentptr = (dir_entry *) do_fat_read_at_block; + /* Strip leading (back-)slashes */ + while ISDIRDELIM(*filename) + ++filename; + /* Check that the filename is valid */ + for (i = 0; i < strlen(illegal); ++i) { + *bad = illegal[i]; + if (strstr(filename, bad)) { + printf("FAT: illegal filename (%s)\n", filename); + return -1; + } + } + name_len = strlen(filename); if (name_len >= VFAT_MAXLEN_BYTES) name_len = VFAT_MAXLEN_BYTES - 1;