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mkfs.btrfs: write zeroes instead on uninitialized data. 

Found by valgrind:
==8968== Use of uninitialised value of size 8
==8968==    at 0x41CE7D: crc32c_le (crc32c.c:98)
==8968==    by 0x40A1D0: csum_tree_block_size (disk-io.c:82)
==8968==    by 0x40A2D4: csum_tree_block (disk-io.c:105)
==8968==    by 0x40A7D6: write_tree_block (disk-io.c:241)
==8968==    by 0x40ACEE: __commit_transaction (disk-io.c:354)
==8968==    by 0x40AE9E: btrfs_commit_transaction (disk-io.c:385)
==8968==    by 0x42CF66: make_image (mkfs.c:1061)
==8968==    by 0x42DE63: main (mkfs.c:1410)
==8968==  Uninitialised value was created by a stack allocation
==8968==    at 0x42B5FB: add_inode_items (mkfs.c:493)

1. On-disk inode format has reserved (and thus, random at alloc time) fields:
   btrfs_inode_item: __le64 reserved[4]
2. Sometimes extents are created on disk without writing data there.
   (Or at least not all data is written there). Kernel code always had
   it kzalloc'ed.
Zero them all.

Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Signed-off-by: Hugo Mills <hugo@carfax.org.uk>
master
Sergei Trofimovich 2011-06-04 11:19:21 +03:00 committed by Chris Mason
parent f509f1762e
commit 8e4b7e883a
2 changed files with 8 additions and 0 deletions
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1
extent_io.c
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@ -568,6 +568,7 @@ static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
BUG();
return NULL;
}
memset(eb, 0, sizeof(struct extent_buffer) + blocksize);
eb->start = bytenr;
eb->len = blocksize;

7
mkfs.c
View File

@ -411,6 +411,13 @@ static int fill_inode_item(struct btrfs_trans_handle *trans,
u64 blocks = 0;
u64 sectorsize = root->sectorsize;
/*
* btrfs_inode_item has some reserved fields
* and represents on-disk inode entry, so
* zero everything to prevent information leak
*/
memset(dst, 0, sizeof (*dst));
btrfs_set_stack_inode_generation(dst, trans->transid);
btrfs_set_stack_inode_size(dst, src->st_size);
btrfs_set_stack_inode_nbytes(dst, 0);