The current function set_name() used to create short names has the following deficiencies resolved by this patch:
* Long names (e.g. FOO.TXT) are stored even if a short name is enough. * Short names with spaces are created, e.g. "A ~1.TXT". * Short names with illegal characters are created, e.g. "FOO++BAR". * Debug output does not not consider that the short file name has no concluding '\0'.
The solution for the following bug is split of into a separate patch:
* Short file names must be unique.
This patch only provides the loop over possible short file names.
Fixes: c30a15e590c ("FAT: Add FAT write feature") Signed-off-by: Heinrich Schuchardt xypron.glpk@gmx.de --- fs/fat/fat_write.c | 215 +++++++++++++++++++++++++++++---------------- lib/Kconfig | 2 +- 2 files changed, 140 insertions(+), 77 deletions(-)
diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c index 4da342f9c9..058b566629 100644 --- a/fs/fat/fat_write.c +++ b/fs/fat/fat_write.c @@ -8,25 +8,140 @@ #include <common.h> #include <command.h> #include <config.h> +#include <div64.h> #include <fat.h> #include <log.h> #include <malloc.h> -#include <asm/byteorder.h> #include <part.h> +#include <rand.h> +#include <asm/byteorder.h> #include <asm/cache.h> #include <linux/ctype.h> -#include <div64.h> #include <linux/math64.h> #include "fat.c"
-static void uppercase(char *str, int len) +/* Characters that may only be used in long file names */ +static const char LONG_ONLY_CHARS[] = "+,;=[]"; + +/** + * str2fat() - convert string to valid FAT name characters + * + * Stop when reaching end of @src or a period. + * Ignore spaces. + * Replace characters that may only be used in long names by underscores. + * Convert lower case characters to upper case. + * + * To avoid assumptions about the code page we do not use characters + * above 0x7f for the short name. + * + * @dest: destination buffer + * @src: source buffer + * @length: size of destination buffer + * Return: number of bytes in destination buffer + */ +static int str2fat(char *dest, char *src, int length) +{ + int i; + + for (i = 0; i < length; ++src) { + char c = *src; + + if (!c || c == '.') + break; + if (c == ' ') + continue; + if (strchr(LONG_ONLY_CHARS, c) || c > 0x7f) + c = '_'; + else if (c >= 'a' && c <= 'z') + c &= 0xdf; + dest[i] = c; + ++i; + } + return i; +} + +/** + * set_name() - set short name in directory entry + * + * The function determines if the @filename is a valid short name. + * In this case no long name is needed. + * + * If a long name is needed, a short name is constructed. + * + * @dirent: directory entry + * @filename: long file name + * Return: number of directory entries needed, negative on error + */ +static int set_name(dir_entry *dirent, const char *filename) { + char *period; + char *pos; + int period_location; + char buf[13]; int i;
- for (i = 0; i < len; i++) { - *str = toupper(*str); - str++; + if (!filename) + return -EIO; + + /* Initialize buffers */ + memset(dirent->name, ' ', sizeof(dirent->name)); + memset(dirent->ext, ' ', sizeof(dirent->ext)); + + /* Convert filename to upper case short name */ + period = strrchr(filename, '.'); + pos = (char *)filename; + if (*pos == '.') { + pos = period + 1; + period = 0; + } + if (period) + str2fat(dirent->ext, period + 1, sizeof(dirent->ext)); + period_location = str2fat(dirent->name, pos, sizeof(dirent->name)); + if (period_location < 0) + return period_location; + if (*dirent->name == ' ') + *dirent->name = '_'; + /* 0xe5 signals a deleted directory entry. Replace it by 0x05. */ + if (*dirent->name == 0xe5) + *dirent->name = 0x05; + + /* If filename and short name are the same, quit. */ + sprintf(buf, "%.*s.%.3s", period_location, dirent->name, dirent->ext); + if (!strcmp(buf, filename)) + return 1; + + /* Construct an indexed short name */ + for (i = 1; i < 0x200000; ++i) { + int suffix_len; + int suffix_start; + int j; + + /* To speed up the search use random numbers */ + if (i < 10) { + j = i; + } else { + j = 30 - fls(i); + j = 10 + (rand() >> j); + } + sprintf(buf, "~%d", j); + suffix_len = strlen(buf); + suffix_start = 8 - suffix_len; + if (suffix_start > period_location) + suffix_start = period_location; + memcpy(dirent->name + suffix_start, buf, suffix_len); + if (*dirent->ext != ' ') + sprintf(buf, "%.*s.%.3s", suffix_start + suffix_len, + dirent->name, dirent->ext); + else + sprintf(buf, "%.*s", suffix_start + suffix_len, + dirent->name); + debug("short name: %s\n", buf); + /* TODO: Check that the short name does not exist yet. */ + + /* Each long name directory entry takes 13 characters. */ + return (strlen(filename) + 25) / 13; } + return -EIO; }
static int total_sector; @@ -50,67 +165,6 @@ static int disk_write(__u32 block, __u32 nr_blocks, void *buf) return ret; }
-/** - * set_name() - set short name in directory entry - * - * @dirent: directory entry - * @filename: long file name - */ -static void set_name(dir_entry *dirent, const char *filename) -{ - char s_name[VFAT_MAXLEN_BYTES]; - char *period; - int period_location, len, i, ext_num; - - if (filename == NULL) - return; - - len = strlen(filename); - if (len == 0) - return; - - strncpy(s_name, filename, VFAT_MAXLEN_BYTES - 1); - s_name[VFAT_MAXLEN_BYTES - 1] = '\0'; - uppercase(s_name, len); - - period = strchr(s_name, '.'); - if (period == NULL) { - period_location = len; - ext_num = 0; - } else { - period_location = period - s_name; - ext_num = len - period_location - 1; - } - - /* Pad spaces when the length of file name is shorter than eight */ - if (period_location < 8) { - memcpy(dirent->name, s_name, period_location); - for (i = period_location; i < 8; i++) - dirent->name[i] = ' '; - } else if (period_location == 8) { - memcpy(dirent->name, s_name, period_location); - } else { - memcpy(dirent->name, s_name, 6); - /* - * TODO: Translating two long names with the same first six - * characters to the same short name is utterly wrong. - * Short names must be unique. - */ - dirent->name[6] = '~'; - dirent->name[7] = '1'; - } - - if (ext_num < 3) { - memcpy(dirent->ext, s_name + period_location + 1, ext_num); - for (i = ext_num; i < 3; i++) - dirent->ext[i] = ' '; - } else - memcpy(dirent->ext, s_name + period_location + 1, 3); - - debug("name : %s\n", dirent->name); - debug("ext : %s\n", dirent->ext); -} - /* * Write fat buffer into block device */ @@ -1181,13 +1235,15 @@ int file_fat_write_at(const char *filename, loff_t pos, void *buffer,
memset(itr->dent, 0, sizeof(*itr->dent));
- /* Calculate checksum for short name */ - set_name(itr->dent, filename); - - /* Set long name entries */ - if (fill_dir_slot(itr, filename)) { - ret = -EIO; + /* Check if long name is needed */ + ret = set_name(itr->dent, filename); + if (ret < 0) goto exit; + if (ret > 1) { + /* Set long name entries */ + ret = fill_dir_slot(itr, filename); + if (ret) + goto exit; }
/* Set short name entry */ @@ -1441,9 +1497,16 @@ int fat_mkdir(const char *new_dirname)
memset(itr->dent, 0, sizeof(*itr->dent));
- /* Set short name to set alias checksum field in dir_slot */ - set_name(itr->dent, dirname); - fill_dir_slot(itr, dirname); + /* Check if long name is needed */ + ret = set_name(itr->dent, dirname); + if (ret < 0) + goto exit; + if (ret > 1) { + /* Set long name entries */ + ret = fill_dir_slot(itr, dirname); + if (ret) + goto exit; + }
/* Set attribute as archive for regular file */ fill_dentry(itr->fsdata, itr->dent, dirname, 0, 0, diff --git a/lib/Kconfig b/lib/Kconfig index 7673d2e4e0..06eb8d07dc 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -168,7 +168,7 @@ config REGEX choice prompt "Pseudo-random library support type" depends on NET_RANDOM_ETHADDR || RANDOM_UUID || CMD_UUID || \ - RNG_SANDBOX || UT_LIB && AES + RNG_SANDBOX || UT_LIB && AES || FAT_WRITE default LIB_RAND help Select the library to provide pseudo-random number generator -- 2.29.2