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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>
michael 17 년 전
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8ce4e5c2c0
2개의 변경된 파일6개의 추가작업 그리고 5개의 파일을 삭제
  1. 4 4
      fs/fat/fat.c
  2. 2 1
      include/fat.h

+ 4 - 4
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;

+ 2 - 1
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 */