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authorNeilBrown <neilb@suse.de>2007-01-26 00:57:03 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-01-26 13:50:59 -0800
commitf49d5e62d9352d33b30c9befbaf0fd9c88265ec1 (patch)
tree32dee76e54b4922eac8ab09c30b1e8399b3107aa
parent1031be7a5fafd3a858dfaabb74d98f9ca20744a8 (diff)
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[PATCH] md: avoid reading past the end of a bitmap file
In most cases we check the size of the bitmap file before reading data from it. However when reading the superblock, we always read the first PAGE_SIZE bytes, which might not always be appropriate. So limit that read to the size of the file if appropriate. Also, we get the count of available bytes wrong in one place, so that too can read past the end of the file. Cc: "yang yin" <yinyang801120@gmail.com> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/md/bitmap.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 5432d07c074..11108165e26 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -479,9 +479,12 @@ static int bitmap_read_sb(struct bitmap *bitmap)
int err = -EINVAL;
/* page 0 is the superblock, read it... */
- if (bitmap->file)
- bitmap->sb_page = read_page(bitmap->file, 0, bitmap, PAGE_SIZE);
- else {
+ if (bitmap->file) {
+ loff_t isize = i_size_read(bitmap->file->f_mapping->host);
+ int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
+
+ bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
+ } else {
bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
}
if (IS_ERR(bitmap->sb_page)) {
@@ -877,7 +880,8 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
int count;
/* unmap the old page, we're done with it */
if (index == num_pages-1)
- count = bytes - index * PAGE_SIZE;
+ count = bytes + sizeof(bitmap_super_t)
+ - index * PAGE_SIZE;
else
count = PAGE_SIZE;
if (index == 0) {