90 lines
3.2 KiB
Diff
90 lines
3.2 KiB
Diff
From: Phillip Lougher <plougher@redhat.com>
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Date: Wed, 2 Nov 2011 13:38:01 -0700
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Subject: [PATCH] hfs: fix hfs_find_init() sb->ext_tree NULL ptr oops
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commit 434a964daa14b9db083ce20404a4a2add54d037a upstream.
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Clement Lecigne reports a filesystem which causes a kernel oops in
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hfs_find_init() trying to dereference sb->ext_tree which is NULL.
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This proves to be because the filesystem has a corrupted MDB extent
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record, where the extents file does not fit into the first three extents
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in the file record (the first blocks).
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In hfs_get_block() when looking up the blocks for the extent file
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(HFS_EXT_CNID), it fails the first blocks special case, and falls
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through to the extent code (which ultimately calls hfs_find_init())
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which is in the process of being initialised.
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Hfs avoids this scenario by always having the extents b-tree fitting
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into the first blocks (the extents B-tree can't have overflow extents).
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The fix is to check at mount time that the B-tree fits into first
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blocks, i.e. fail if HFS_I(inode)->alloc_blocks >=
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HFS_I(inode)->first_blocks
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Note, the existing commit 47f365eb57573 ("hfs: fix oops on mount with
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corrupted btree extent records") becomes subsumed into this as a special
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case, but only for the extents B-tree (HFS_EXT_CNID), it is perfectly
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acceptable for the catalog B-Tree file to grow beyond three extents,
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with the remaining extent descriptors in the extents overfow.
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This fixes CVE-2011-2203
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Reported-by: Clement LECIGNE <clement.lecigne@netasq.com>
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Signed-off-by: Phillip Lougher <plougher@redhat.com>
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Cc: Jeff Mahoney <jeffm@suse.com>
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Cc: Christoph Hellwig <hch@lst.de>
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Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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---
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fs/hfs/btree.c | 20 +++++++++++++++-----
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1 files changed, 15 insertions(+), 5 deletions(-)
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diff --git a/fs/hfs/btree.c b/fs/hfs/btree.c
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index 3ebc437..1cbdeea 100644
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--- a/fs/hfs/btree.c
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+++ b/fs/hfs/btree.c
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@@ -46,11 +46,26 @@ struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp ke
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case HFS_EXT_CNID:
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hfs_inode_read_fork(tree->inode, mdb->drXTExtRec, mdb->drXTFlSize,
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mdb->drXTFlSize, be32_to_cpu(mdb->drXTClpSiz));
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+ if (HFS_I(tree->inode)->alloc_blocks >
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+ HFS_I(tree->inode)->first_blocks) {
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+ printk(KERN_ERR "hfs: invalid btree extent records\n");
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+ unlock_new_inode(tree->inode);
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+ goto free_inode;
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+ }
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+
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tree->inode->i_mapping->a_ops = &hfs_btree_aops;
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break;
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case HFS_CAT_CNID:
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hfs_inode_read_fork(tree->inode, mdb->drCTExtRec, mdb->drCTFlSize,
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mdb->drCTFlSize, be32_to_cpu(mdb->drCTClpSiz));
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+
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+ if (!HFS_I(tree->inode)->first_blocks) {
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+ printk(KERN_ERR "hfs: invalid btree extent records "
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+ "(0 size).\n");
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+ unlock_new_inode(tree->inode);
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+ goto free_inode;
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+ }
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+
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tree->inode->i_mapping->a_ops = &hfs_btree_aops;
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break;
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default:
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@@ -59,11 +74,6 @@ struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp ke
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}
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unlock_new_inode(tree->inode);
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- if (!HFS_I(tree->inode)->first_blocks) {
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- printk(KERN_ERR "hfs: invalid btree extent records (0 size).\n");
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- goto free_inode;
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- }
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-
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mapping = tree->inode->i_mapping;
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page = read_mapping_page(mapping, 0, NULL);
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if (IS_ERR(page))
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--
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1.7.7.2
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