From: Baokun Li <libaokun1@huawei.com>
To: <linux-ext4@vger.kernel.org>
Cc: <tytso@mit.edu>, <adilger.kernel@dilger.ca>, <jack@suse.cz>,
<ritesh.list@gmail.com>, <linux-kernel@vger.kernel.org>,
<yi.zhang@huawei.com>, <yukuai3@huawei.com>,
<libaokun1@huawei.com>
Subject: [PATCH v3 3/4] ext4: add EXT4_IGET_BAD flag to prevent unexpected bad inode
Date: Wed, 26 Oct 2022 12:23:09 +0800 [thread overview]
Message-ID: <20221026042310.3839669-4-libaokun1@huawei.com> (raw)
In-Reply-To: <20221026042310.3839669-1-libaokun1@huawei.com>
There are many places that will get unhappy (and crash) when ext4_iget()
returns a bad inode. However, if iget the boot loader inode, allows a bad
inode to be returned, because the inode may not be initialized. This
mechanism can be used to bypass some checks and cause panic. To solve this
problem, we add a special iget flag EXT4_IGET_BAD. Only with this flag
we'd be returning bad inode from ext4_iget(), otherwise we always return
the error code if the inode is bad inode.(suggested by Jan Kara)
Signed-off-by: Baokun Li <libaokun1@huawei.com>
---
fs/ext4/ext4.h | 3 ++-
fs/ext4/inode.c | 8 +++++++-
fs/ext4/ioctl.c | 3 ++-
3 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 8d5453852f98..2b574b143bde 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2964,7 +2964,8 @@ int do_journal_get_write_access(handle_t *handle, struct inode *inode,
typedef enum {
EXT4_IGET_NORMAL = 0,
EXT4_IGET_SPECIAL = 0x0001, /* OK to iget a system inode */
- EXT4_IGET_HANDLE = 0x0002 /* Inode # is from a handle */
+ EXT4_IGET_HANDLE = 0x0002, /* Inode # is from a handle */
+ EXT4_IGET_BAD = 0x0004 /* Allow to iget a bad inode */
} ext4_iget_flags;
extern struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ae3a836dd9d7..f767340229fd 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5043,8 +5043,14 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
if (IS_CASEFOLDED(inode) && !ext4_has_feature_casefold(inode->i_sb))
ext4_error_inode(inode, function, line, 0,
"casefold flag without casefold feature");
- brelse(iloc.bh);
+ if (is_bad_inode(inode) && !(flags & EXT4_IGET_BAD)) {
+ ext4_error_inode(inode, function, line, 0,
+ "bad inode without EXT4_IGET_BAD flag");
+ ret = -EUCLEAN;
+ goto bad_inode;
+ }
+ brelse(iloc.bh);
unlock_new_inode(inode);
return inode;
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index ded535535b27..e0be8026c996 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -375,7 +375,8 @@ static long swap_inode_boot_loader(struct super_block *sb,
blkcnt_t blocks;
unsigned short bytes;
- inode_bl = ext4_iget(sb, EXT4_BOOT_LOADER_INO, EXT4_IGET_SPECIAL);
+ inode_bl = ext4_iget(sb, EXT4_BOOT_LOADER_INO,
+ EXT4_IGET_SPECIAL | EXT4_IGET_BAD);
if (IS_ERR(inode_bl))
return PTR_ERR(inode_bl);
ei_bl = EXT4_I(inode_bl);
--
2.31.1
next prev parent reply other threads:[~2022-10-26 4:01 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-26 4:23 [PATCH v3 0/4] ext4: fix two bug_on in __es_tree_search Baokun Li
2022-10-26 4:23 ` [PATCH v3 1/4] ext4: fix bug_on in __es_tree_search caused by bad quota inode Baokun Li
2022-10-26 9:36 ` Jan Kara
2022-10-26 13:56 ` Jason Yan
2022-10-26 18:33 ` Chaitanya Kulkarni
2022-10-26 4:23 ` [PATCH v3 2/4] ext4: add helper to check quota inums Baokun Li
2022-10-26 9:38 ` Jan Kara
2022-10-26 13:57 ` Jason Yan
2022-10-26 4:23 ` Baokun Li [this message]
2022-10-26 9:41 ` [PATCH v3 3/4] ext4: add EXT4_IGET_BAD flag to prevent unexpected bad inode Jan Kara
2022-10-26 13:59 ` Jason Yan
2022-10-26 4:23 ` [PATCH v3 4/4] ext4: fix bug_on in __es_tree_search caused by bad boot loader inode Baokun Li
2022-10-26 10:12 ` Jan Kara
2022-10-26 14:05 ` Jason Yan
2022-12-06 21:01 ` [PATCH v3 0/4] ext4: fix two bug_on in __es_tree_search Theodore Ts'o
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