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Message-Id: <20230524034951.779531-2-tytso@mit.edu>
Date: Tue, 23 May 2023 23:49:48 -0400
From: "Theodore Ts'o" <tytso@....edu>
To: Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc: "Theodore Ts'o" <tytso@....edu>,
syzbot+cbb68193bdb95af4340a@...kaller.appspotmail.com,
syzbot+62120febbd1ee3c3c860@...kaller.appspotmail.com,
syzbot+edce54daffee36421b4c@...kaller.appspotmail.com,
stable@...nel.org
Subject: [PATCH 1/4] ext4: add EA_INODE checking to ext4_iget()
Add a new flag, EXT4_IGET_EA_INODE which indicates whether the inode
is expected to have the EA_INODE flag or not. If the flag is not
set/clear as expected, then fail the iget() operation and mark the
file system as corrupted.
This commit also makes the ext4_iget() always perform the
is_bad_inode() check even when the inode is already inode cache. This
allows us to remove the is_bad_inode() check from the callers of
ext4_iget() in the ea_inode code.
Reported-by: syzbot+cbb68193bdb95af4340a@...kaller.appspotmail.com
Reported-by: syzbot+62120febbd1ee3c3c860@...kaller.appspotmail.com
Reported-by: syzbot+edce54daffee36421b4c@...kaller.appspotmail.com
Signed-off-by: Theodore Ts'o <tytso@....edu>
Cc: stable@...nel.org
---
fs/ext4/ext4.h | 3 ++-
fs/ext4/inode.c | 31 ++++++++++++++++++++++++++-----
fs/ext4/xattr.c | 36 +++++++-----------------------------
3 files changed, 35 insertions(+), 35 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 6948d673bba2..9525c52b78dc 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2901,7 +2901,8 @@ 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_BAD = 0x0004 /* Allow to iget a bad inode */
+ EXT4_IGET_BAD = 0x0004, /* Allow to iget a bad inode */
+ EXT4_IGET_EA_INODE = 0x0008 /* Inode should contain an EA value */
} 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 ce5f21b6c2b3..258f3cbed347 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4641,6 +4641,21 @@ static inline void ext4_inode_set_iversion_queried(struct inode *inode, u64 val)
inode_set_iversion_queried(inode, val);
}
+static const char *check_igot_inode(struct inode *inode, ext4_iget_flags flags)
+
+{
+ if (flags & EXT4_IGET_EA_INODE) {
+ if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
+ return "missing EA_INODE flag";
+ } else {
+ if ((EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
+ return "unexpected EA_INODE flag";
+ }
+ if (is_bad_inode(inode) && !(flags & EXT4_IGET_BAD))
+ return "unexpected bad inode w/o EXT4_IGET_BAD";
+ return NULL;
+}
+
struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
ext4_iget_flags flags, const char *function,
unsigned int line)
@@ -4650,6 +4665,7 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
struct ext4_inode_info *ei;
struct ext4_super_block *es = EXT4_SB(sb)->s_es;
struct inode *inode;
+ const char *err_str;
journal_t *journal = EXT4_SB(sb)->s_journal;
long ret;
loff_t size;
@@ -4677,8 +4693,14 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
inode = iget_locked(sb, ino);
if (!inode)
return ERR_PTR(-ENOMEM);
- if (!(inode->i_state & I_NEW))
+ if (!(inode->i_state & I_NEW)) {
+ if ((err_str = check_igot_inode(inode, flags)) != NULL) {
+ ext4_error_inode(inode, function, line, 0, err_str);
+ iput(inode);
+ return ERR_PTR(-EFSCORRUPTED);
+ }
return inode;
+ }
ei = EXT4_I(inode);
iloc.bh = NULL;
@@ -4944,10 +4966,9 @@ 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");
- 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;
+ if ((err_str = check_igot_inode(inode, flags)) != NULL) {
+ ext4_error_inode(inode, function, line, 0, err_str);
+ ret = -EFSCORRUPTED;
goto bad_inode;
}
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index dfc2e223bd10..a27208129a80 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -433,7 +433,7 @@ static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
return -EFSCORRUPTED;
}
- inode = ext4_iget(parent->i_sb, ea_ino, EXT4_IGET_NORMAL);
+ inode = ext4_iget(parent->i_sb, ea_ino, EXT4_IGET_EA_INODE);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
ext4_error(parent->i_sb,
@@ -441,23 +441,6 @@ static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
err);
return err;
}
-
- if (is_bad_inode(inode)) {
- ext4_error(parent->i_sb,
- "error while reading EA inode %lu is_bad_inode",
- ea_ino);
- err = -EIO;
- goto error;
- }
-
- if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
- ext4_error(parent->i_sb,
- "EA inode %lu does not have EXT4_EA_INODE_FL flag",
- ea_ino);
- err = -EINVAL;
- goto error;
- }
-
ext4_xattr_inode_set_class(inode);
/*
@@ -478,9 +461,6 @@ static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
*ea_inode = inode;
return 0;
-error:
- iput(inode);
- return err;
}
/* Remove entry from mbcache when EA inode is getting evicted */
@@ -1556,11 +1536,10 @@ ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
while (ce) {
ea_inode = ext4_iget(inode->i_sb, ce->e_value,
- EXT4_IGET_NORMAL);
- if (!IS_ERR(ea_inode) &&
- !is_bad_inode(ea_inode) &&
- (EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) &&
- i_size_read(ea_inode) == value_len &&
+ EXT4_IGET_EA_INODE);
+ if (IS_ERR(ea_inode))
+ goto next_entry;
+ if (i_size_read(ea_inode) == value_len &&
!ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
!ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
value_len) &&
@@ -1570,9 +1549,8 @@ ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
kvfree(ea_data);
return ea_inode;
}
-
- if (!IS_ERR(ea_inode))
- iput(ea_inode);
+ iput(ea_inode);
+ next_entry:
ce = mb_cache_entry_find_next(ea_inode_cache, ce);
}
kvfree(ea_data);
--
2.31.0
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