Fix checking fat32 cluster size.

This fixes the cluster size tests in the FAT32 file system.
The current implementation of VFAT support doesn't work if the
referred cluster has an offset > 16bit representation, causing
"fatload" and "fatls" commands etc. to fail.

Signed-off-by: michael trimarchi <trimarchi@gandalf.sssup.it>

diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index c1e57412d77994b6a03789346a6d45b1a31de123..49c78ed79ac000aa5eb3259fdb51aa011fc94cdf 100644 (file)
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -352,7 +352,7 @@ get_contents(fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
                        newclust = get_fatent(mydata, endclust);
                        if((newclust -1)!=endclust)
                                goto getit;
-                       if (newclust <= 0x0001 || newclust >= 0xfff0) {
+                       if (CHECK_CLUST(newclust, mydata->fatsize)) {
                                FAT_DPRINT("curclust: 0x%x\n", newclust);
                                FAT_DPRINT("Invalid FAT entry\n");
                                return gotsize;
@@ -387,7 +387,7 @@ getit:
                filesize -= actsize;
                buffer += actsize;
                curclust = get_fatent(mydata, endclust);
-               if (curclust <= 0x0001 || curclust >= 0xfff0) {
+               if (CHECK_CLUST(curclust, mydata->fatsize)) {
                        FAT_DPRINT("curclust: 0x%x\n", curclust);
                        FAT_ERROR("Invalid FAT entry\n");
                        return gotsize;
@@ -459,7 +459,7 @@ get_vfatname(fsdata *mydata, int curclust, __u8 *cluster,
 
                slotptr--;
                curclust = get_fatent(mydata, curclust);
-               if (curclust <= 0x0001 || curclust >= 0xfff0) {
+               if (CHECK_CLUST(curclust, mydata->fatsize)) {
                        FAT_DPRINT("curclust: 0x%x\n", curclust);
                        FAT_ERROR("Invalid FAT entry\n");
                        return -1;
@@ -652,7 +652,7 @@ static dir_entry *get_dentfromdir (fsdata * mydata, int startsect,
            return retdent;
        }
        curclust = get_fatent (mydata, curclust);
-       if (curclust <= 0x0001 || curclust >= 0xfff0) {
+       if (CHECK_CLUST(curclust, mydata->fatsize)) {
            FAT_DPRINT ("curclust: 0x%x\n", curclust);
            FAT_ERROR ("Invalid FAT entry\n");
            return NULL;

diff --git a/include/fat.h b/include/fat.h
index 92638d535e4def9e99a694d6842a04840f4423b7..f993ccab1c2c2a20d4340dc162dbef9cd297256a 100644 (file)
--- a/include/fat.h
+++ b/include/fat.h
@@ -111,7 +111,8 @@
 #define START(dent)    (FAT2CPU16((dent)->start) \
                        + (mydata->fatsize != 32 ? 0 : \
                          (FAT2CPU16((dent)->starthi) << 16)))
-
+#define CHECK_CLUST(x, fatsize) ((x) <= 1 || \
+                               (x) >= ((fatsize) != 32 ? 0xfff0 : 0xffffff0))
 
 typedef struct boot_sector {
        __u8    ignored[3];     /* Bootstrap code */