Merge pull request #7902 from orenc17/fat_fix

Cruz Monrreal · web-flow · commit 2b04a02eb257 · 2018-10-11T10:08:46.000-05:00
Fix overflow in disk_get_sector_size()
diff --git a/features/storage/filesystem/fat/FATFileSystem.cpp b/features/storage/filesystem/fat/FATFileSystem.cpp
@@ -168,7 +168,10 @@ void ff_memfree(void *p)
 // Implementation of diskio functions (see ChaN/diskio.h)
 static WORD disk_get_sector_size(BYTE pdrv)
 {
-    WORD ssize = _ffs[pdrv]->get_erase_size();
+    bd_size_t sector_size = _ffs[pdrv]->get_erase_size();
+    MBED_ASSERT(sector_size <= WORD(-1));
+
+    WORD ssize = sector_size;
     if (ssize < 512) {
         ssize = 512;
     }

Original file line number	Diff line number	Diff line change
`@@ -168,7 +168,10 @@ void ff_memfree(void *p)`
`168`	`168`	`// Implementation of diskio functions (see ChaN/diskio.h)`
`169`	`169`	`static WORD disk_get_sector_size(BYTE pdrv)`
`170`	`170`	`{`
`171`		`- WORD ssize = _ffs[pdrv]->get_erase_size();`
	`171`	`+ bd_size_t sector_size = _ffs[pdrv]->get_erase_size();`
	`172`	`+ MBED_ASSERT(sector_size <= WORD(-1));`
	`173`	`+`
	`174`	`+ WORD ssize = sector_size;`
`172`	`175`	`if (ssize < 512) {`
`173`	`176`	`ssize = 512;`
`174`	`177`	`}`