linux-kernel - [PATCH 3.18 117/120] ext4: avoid running out of journal credits when appending to an inline file

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20181011152554.630158762@linuxfoundation.org>
Date:   Thu, 11 Oct 2018 17:34:58 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Theodore Tso <tytso@....edu>,
        Ben Hutchings <ben@...adent.org.uk>,
        Greg Hackmann <ghackmann@...gle.com>
Subject: [PATCH 3.18 117/120] ext4: avoid running out of journal credits when appending to an inline file

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Theodore Ts'o <tytso@....edu>

commit 8bc1379b82b8e809eef77a9fedbb75c6c297be19 upstream.

Use a separate journal transaction if it turns out that we need to
convert an inline file to use an data block.  Otherwise we could end
up failing due to not having journal credits.

This addresses CVE-2018-10883.

https://bugzilla.kernel.org/show_bug.cgi?id=200071

Signed-off-by: Theodore Ts'o <tytso@....edu>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
Signed-off-by: Greg Hackmann <ghackmann@...gle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/ext4/ext4.h   |    3 ---
 fs/ext4/inline.c |   38 +-------------------------------------
 fs/ext4/xattr.c  |   18 ++----------------
 3 files changed, 3 insertions(+), 56 deletions(-)

--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2663,9 +2663,6 @@ extern struct buffer_head *ext4_get_firs
 extern int ext4_inline_data_fiemap(struct inode *inode,
 				   struct fiemap_extent_info *fieinfo,
 				   int *has_inline);
-extern int ext4_try_to_evict_inline_data(handle_t *handle,
-					 struct inode *inode,
-					 int needed);
 extern void ext4_inline_data_truncate(struct inode *inode, int *has_inline);
 
 extern int ext4_convert_inline_data(struct inode *inode);
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -873,11 +873,11 @@ retry_journal:
 	}
 
 	if (ret == -ENOSPC) {
+		ext4_journal_stop(handle);
 		ret = ext4_da_convert_inline_data_to_extent(mapping,
 							    inode,
 							    flags,
 							    fsdata);
-		ext4_journal_stop(handle);
 		if (ret == -ENOSPC &&
 		    ext4_should_retry_alloc(inode->i_sb, &retries))
 			goto retry_journal;
@@ -1842,42 +1842,6 @@ out:
 	return (error < 0 ? error : 0);
 }
 
-/*
- * Called during xattr set, and if we can sparse space 'needed',
- * just create the extent tree evict the data to the outer block.
- *
- * We use jbd2 instead of page cache to move data to the 1st block
- * so that the whole transaction can be committed as a whole and
- * the data isn't lost because of the delayed page cache write.
- */
-int ext4_try_to_evict_inline_data(handle_t *handle,
-				  struct inode *inode,
-				  int needed)
-{
-	int error;
-	struct ext4_xattr_entry *entry;
-	struct ext4_inode *raw_inode;
-	struct ext4_iloc iloc;
-
-	error = ext4_get_inode_loc(inode, &iloc);
-	if (error)
-		return error;
-
-	raw_inode = ext4_raw_inode(&iloc);
-	entry = (struct ext4_xattr_entry *)((void *)raw_inode +
-					    EXT4_I(inode)->i_inline_off);
-	if (EXT4_XATTR_LEN(entry->e_name_len) +
-	    EXT4_XATTR_SIZE(le32_to_cpu(entry->e_value_size)) < needed) {
-		error = -ENOSPC;
-		goto out;
-	}
-
-	error = ext4_convert_inline_data_nolock(handle, inode, &iloc);
-out:
-	brelse(iloc.bh);
-	return error;
-}
-
 void ext4_inline_data_truncate(struct inode *inode, int *has_inline)
 {
 	handle_t *handle;
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1045,22 +1045,8 @@ int ext4_xattr_ibody_inline_set(handle_t
 	if (EXT4_I(inode)->i_extra_isize == 0)
 		return -ENOSPC;
 	error = ext4_xattr_set_entry(i, s, inode);
-	if (error) {
-		if (error == -ENOSPC &&
-		    ext4_has_inline_data(inode)) {
-			error = ext4_try_to_evict_inline_data(handle, inode,
-					EXT4_XATTR_LEN(strlen(i->name) +
-					EXT4_XATTR_SIZE(i->value_len)));
-			if (error)
-				return error;
-			error = ext4_xattr_ibody_find(inode, i, is);
-			if (error)
-				return error;
-			error = ext4_xattr_set_entry(i, s, inode);
-		}
-		if (error)
-			return error;
-	}
+	if (error)
+		return error;
 	header = IHDR(inode, ext4_raw_inode(&is->iloc));
 	if (!IS_LAST_ENTRY(s->first)) {
 		header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);