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-rw-r--r--fs/fat/fat_write.c27
1 files changed, 27 insertions, 0 deletions
diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c
index 90d6ab63bf..ba7e3aeb0b 100644
--- a/fs/fat/fat_write.c
+++ b/fs/fat/fat_write.c
@@ -139,6 +139,11 @@ static __u32 get_fatent_value(fsdata *mydata, __u32 entry)
__u32 ret = 0x00;
__u16 val1, val2;
+ if (CHECK_CLUST(entry, mydata->fatsize)) {
+ printf("Error: Invalid FAT entry: 0x%08x\n", entry);
+ return ret;
+ }
+
switch (mydata->fatsize) {
case 32:
bufnum = entry / FAT32BUFSIZE;
@@ -881,6 +886,28 @@ static dir_entry *find_directory_entry(fsdata *mydata, int startsect,
return dentptr;
}
+ /*
+ * In FAT16/12, the root dir is locate before data area, shows
+ * in following:
+ * -------------------------------------------------------------
+ * | Boot | FAT1 & 2 | Root dir | Data (start from cluster #2) |
+ * -------------------------------------------------------------
+ *
+ * As a result if curclust is in Root dir, it is a negative
+ * number or 0, 1.
+ *
+ */
+ if (mydata->fatsize != 32 && (int)curclust <= 1) {
+ /* Current clust is in root dir, set to next clust */
+ curclust++;
+ if ((int)curclust <= 1)
+ continue; /* continue to find */
+
+ /* Reach the end of root dir */
+ empty_dentptr = dentptr;
+ return NULL;
+ }
+
curclust = get_fatent_value(mydata, dir_curclust);
if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
empty_dentptr = dentptr;
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