From c7a86d1645325697372b404f0b8cadac8a722ce9 Mon Sep 17 00:00:00 2001
From: Heinrich Schuchardt <xypron.glpk@gmx.de>
Date: Thu, 12 Sep 2019 19:19:29 +0200
Subject: [PATCH] fs: fat: treat invalid FAT clusters as errors
When hitting an invalid FAT cluster while reading a file always print an
error message and return an error code.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
---
fs/fat/fat.c | 30 ++++++++++++++++++++----------
1 file changed, 20 insertions(+), 10 deletions(-)
diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index 29cae8d391..2a5300d501 100644
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -301,10 +301,20 @@ get_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer, unsigned long size)
return 0;
}
-/*
+/**
+ * get_contents() - read from file
+ *
* Read at most 'maxsize' bytes from 'pos' in the file associated with 'dentptr'
- * into 'buffer'.
- * Update the number of bytes read in *gotsize or return -1 on fatal errors.
+ * into 'buffer'. Update the number of bytes read in *gotsize or return -1 on
+ * fatal errors.
+ *
+ * @mydata: file system description
+ * @dentprt: directory entry pointer
+ * @pos: position from where to read
+ * @buffer: buffer into which to read
+ * @maxsize: maximum number of bytes to read
+ * @gotsize: number of bytes actually read
+ * Return: -1 on error, otherwise 0
*/
static int get_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos,
__u8 *buffer, loff_t maxsize, loff_t *gotsize)
@@ -335,8 +345,8 @@ static int get_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos,
curclust = get_fatent(mydata, curclust);
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
- debug("Invalid FAT entry\n");
- return 0;
+ printf("Invalid FAT entry\n");
+ return -1;
}
actsize += bytesperclust;
}
@@ -374,8 +384,8 @@ static int get_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos,
curclust = get_fatent(mydata, curclust);
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
- debug("Invalid FAT entry\n");
- return 0;
+ printf("Invalid FAT entry\n");
+ return -1;
}
}
@@ -390,8 +400,8 @@ static int get_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos,
goto getit;
if (CHECK_CLUST(newclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", newclust);
- debug("Invalid FAT entry\n");
- return 0;
+ printf("Invalid FAT entry\n");
+ return -1;
}
endclust = newclust;
actsize += bytesperclust;
@@ -418,7 +428,7 @@ getit:
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
printf("Invalid FAT entry\n");
- return 0;
+ return -1;
}
actsize = bytesperclust;
endclust = curclust;
--
2.39.5