fs: fat: Fix mkcksum() function parameters

The mkcksum() function now takes one parameter, the pointer to
11-byte wide character array, which it then operates on.

Currently, the function is wrongly passed (dir_entry)->name, which
is only 8-byte wide character array. Though by further inspecting
the dir_entry structure, it can be noticed that the name[8] entry
is immediatelly followed by ext[3] entry. Thus, name[8] and ext[3]
in the dir_entry structure actually work as this 11-byte wide array
since they're placed right next to each other by current compiler
behavior.

Depending on this is obviously wrong, thus fix this by correctly
passing both (dir_entry)->name and (dir_entry)->ext to the mkcksum()
function and adjust the function appropriately.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Tom Rini <trini@ti.com>

diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index 80156c8..4a60a25 100644 (file)
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -567,15 +567,16 @@ get_vfatname(fsdata *mydata, int curclust, __u8 *cluster,
 }
 
 /* Calculate short name checksum */
-static __u8 mkcksum(const char *str)
+static __u8 mkcksum(const char name[8], const char ext[3])
 {
        int i;
 
        __u8 ret = 0;
 
-       for (i = 0; i < 11; i++) {
-               ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + str[i];
-       }
+       for (i = 0; i < sizeof(name); i++)
+               ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + name[i];
+       for (i = 0; i < sizeof(ext); i++)
+               ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + ext[i];
 
        return ret;
 }
@@ -678,7 +679,8 @@ static dir_entry *get_dentfromdir(fsdata *mydata, int startsect,
                                return NULL;
                        }
 #ifdef CONFIG_SUPPORT_VFAT
-                       if (dols && mkcksum(dentptr->name) == prevcksum) {
+                       __u8 csum = mkcksum(dentptr->name, dentptr->ext);
+                       if (dols && csum == prevcksum) {
                                prevcksum = 0xffff;
                                dentptr++;
                                continue;
@@ -946,13 +948,16 @@ do_fat_read_at(const char *filename, unsigned long pos, void *buffer,
 
                for (i = 0; i < DIRENTSPERBLOCK; i++) {
                        char s_name[14], l_name[VFAT_MAXLEN_BYTES];
+                       __u8 csum;
 
                        l_name[0] = '\0';
                        if (dentptr->name[0] == DELETED_FLAG) {
                                dentptr++;
                                continue;
                        }
-                       if ((dentptr->attr & ATTR_VOLUME)) {
+
+                       csum = mkcksum(dentptr->name, dentptr->ext);
+                       if (dentptr->attr & ATTR_VOLUME) {
 #ifdef CONFIG_SUPPORT_VFAT
                                if ((dentptr->attr & ATTR_VFAT) == ATTR_VFAT &&
                                    (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
@@ -1015,8 +1020,7 @@ do_fat_read_at(const char *filename, unsigned long pos, void *buffer,
                                goto exit;
                        }
 #ifdef CONFIG_SUPPORT_VFAT
-                       else if (dols == LS_ROOT &&
-                                mkcksum(dentptr->name) == prevcksum) {
+                       else if (dols == LS_ROOT && csum == prevcksum) {
                                prevcksum = 0xffff;
                                dentptr++;
                                continue;

diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c
index 5829adf..4a1bda0 100644 (file)
--- a/fs/fat/fat_write.c
+++ b/fs/fat/fat_write.c
@@ -335,7 +335,7 @@ fill_dir_slot(fsdata *mydata, dir_entry **dentptr, const char *l_name)
 
        /* Get short file name and checksum value */
        strncpy(s_name, (*dentptr)->name, 16);
-       checksum = mkcksum(s_name);
+       checksum = mkcksum((*dentptr)->name, (*dentptr)->ext);
 
        do {
                memset(slotptr, 0x00, sizeof(dir_slot));