2020-04-29 20:47:29

by ashwin-h

[permalink] [raw]
Subject: [PATCH 0/5] Backport to 4.4 - ext4: protect journal inode's blocks using block_validity

[PATCH 1/5] ext4: avoid declaring fs inconsistent due to invalid file
handles
This patch is backported as functionality in this commit is used by
Patch 2 in this patchset.

[PATCH 2/5] ext4: protect journal inode's blocks using block_validity
Backport to 4.4

[PATCH 3/5] ext4: don't perform block validity checks on the journal
[PATCH 4/5] ext4: fix block validity checks for journal inodes using
[PATCH 5/5] ext4: unsigned int compared against zero
Fixes issues found in Patch 2 in this patchset.


These patches addresses CVE-2019-19319

Colin Ian King (1):
ext4: unsigned int compared against zero

Theodore Ts'o (4):
ext4: avoid declaring fs inconsistent due to invalid file handles
ext4: protect journal inode's blocks using block_validity
ext4: don't perform block validity checks on the journal inode
ext4: fix block validity checks for journal inodes using indirect
blocks

fs/ext4/block_validity.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++
fs/ext4/ext4.h | 15 ++++++++++++--
fs/ext4/extents.c | 12 +++++++----
fs/ext4/ialloc.c | 2 +-
fs/ext4/inode.c | 48 ++++++++++++++++++++++++++++++------------
fs/ext4/ioctl.c | 2 +-
fs/ext4/namei.c | 4 ++--
fs/ext4/resize.c | 5 +++--
fs/ext4/super.c | 28 +++++++++----------------
9 files changed, 127 insertions(+), 43 deletions(-)

--
2.7.4


2020-04-29 20:47:41

by ashwin-h

[permalink] [raw]
Subject: [PATCH 3/5] ext4: don't perform block validity checks on the journal inode

From: Theodore Ts'o <[email protected]>

commit 0a944e8a6c66ca04c7afbaa17e22bf208a8b37f0 upstream.

Since the journal inode is already checked when we added it to the
block validity's system zone, if we check it again, we'll just trigger
a failure.

This was causing failures like this:

[ 53.897001] EXT4-fs error (device sda): ext4_find_extent:909: inode
#8: comm jbd2/sda-8: pblk 121667583 bad header/extent: invalid extent entries - magic f30a, entries 8, max 340(340), depth 0(0)
[ 53.931430] jbd2_journal_bmap: journal block not found at offset 49 on sda-8
[ 53.938480] Aborting journal on device sda-8.

... but only if the system was under enough memory pressure that
logical->physical mapping for the journal inode gets pushed out of the
extent cache. (This is why it wasn't noticed earlier.)

Fixes: 345c0dbf3a30 ("ext4: protect journal inode's blocks using block_validity")
Reported-by: Dan Rue <[email protected]>
Signed-off-by: Theodore Ts'o <[email protected]>
Tested-by: Naresh Kamboju <[email protected]>
Signed-off-by: Ashwin H <[email protected]>
---
fs/ext4/extents.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 8d98c9a..71492bf 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -525,10 +525,14 @@ __read_extent_tree_block(const char *function, unsigned int line,
}
if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
return bh;
- err = __ext4_ext_check(function, line, inode,
- ext_block_hdr(bh), depth, pblk);
- if (err)
- goto errout;
+ if (!ext4_has_feature_journal(inode->i_sb) ||
+ (inode->i_ino !=
+ le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum))) {
+ err = __ext4_ext_check(function, line, inode,
+ ext_block_hdr(bh), depth, pblk);
+ if (err)
+ goto errout;
+ }
set_buffer_verified(bh);
/*
* If this is a leaf block, cache all of its entries
--
2.7.4

2020-04-29 20:47:59

by ashwin-h

[permalink] [raw]
Subject: [PATCH 4/5] ext4: fix block validity checks for journal inodes using indirect blocks

From: Theodore Ts'o <[email protected]>

commit 170417c8c7bb2cbbdd949bf5c443c0c8f24a203b upstream.

Commit 345c0dbf3a30 ("ext4: protect journal inode's blocks using
block_validity") failed to add an exception for the journal inode in
ext4_check_blockref(), which is the function used by ext4_get_branch()
for indirect blocks. This caused attempts to read from the ext3-style
journals to fail with:

[ 848.968550] EXT4-fs error (device sdb7): ext4_get_branch:171: inode #8: block 30343695: comm jbd2/sdb7-8: invalid block

Fix this by adding the missing exception check.

Fixes: 345c0dbf3a30 ("ext4: protect journal inode's blocks using block_validity")
Reported-by: Arthur Marsh <[email protected]>
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Ashwin H <[email protected]>
---
fs/ext4/block_validity.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c
index 093639b..3f3d82d 100644
--- a/fs/ext4/block_validity.c
+++ b/fs/ext4/block_validity.c
@@ -274,6 +274,11 @@ int ext4_check_blockref(const char *function, unsigned int line,
__le32 *bref = p;
unsigned int blk;

+ if (ext4_has_feature_journal(inode->i_sb) &&
+ (inode->i_ino ==
+ le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
+ return 0;
+
while (bref < p+max) {
blk = le32_to_cpu(*bref++);
if (blk &&
--
2.7.4

2020-04-29 20:51:17

by ashwin-h

[permalink] [raw]
Subject: [PATCH 1/5] ext4: avoid declaring fs inconsistent due to invalid file handles

From: Theodore Ts'o <[email protected]>

commit 8a363970d1dc38c4ec4ad575c862f776f468d057 upstream.

If we receive a file handle, either from NFS or open_by_handle_at(2),
and it points at an inode which has not been initialized, and the file
system has metadata checksums enabled, we shouldn't try to get the
inode, discover the checksum is invalid, and then declare the file
system as being inconsistent.

This can be reproduced by creating a test file system via "mke2fs -t
ext4 -O metadata_csum /tmp/foo.img 8M", mounting it, cd'ing into that
directory, and then running the following program.

struct handle {
struct file_handle fh;
unsigned char fid[MAX_HANDLE_SZ];
};

int main(int argc, char **argv)
{
struct handle h = {{8, 1 }, { 12, }};

open_by_handle_at(AT_FDCWD, &h.fh, O_RDONLY);
return 0;
}

Google-Bug-Id: 120690101
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Ashwin H <[email protected]>
Cc: [email protected]
---
fs/ext4/ext4.h | 15 +++++++++++++--
fs/ext4/ialloc.c | 2 +-
fs/ext4/inode.c | 44 +++++++++++++++++++++++++++++++-------------
fs/ext4/ioctl.c | 2 +-
fs/ext4/namei.c | 4 ++--
fs/ext4/resize.c | 5 +++--
fs/ext4/super.c | 28 ++++++++++------------------
7 files changed, 61 insertions(+), 39 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index ab0f08c..de475259 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2497,8 +2497,19 @@ int do_journal_get_write_access(handle_t *handle,
#define FALL_BACK_TO_NONDELALLOC 1
#define CONVERT_INLINE_DATA 2

-extern struct inode *ext4_iget(struct super_block *, unsigned long);
-extern struct inode *ext4_iget_normal(struct super_block *, unsigned long);
+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_flags;
+
+extern struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
+ ext4_iget_flags flags, const char *function,
+ unsigned int line);
+
+#define ext4_iget(sb, ino, flags) \
+ __ext4_iget((sb), (ino), (flags), __func__, __LINE__)
+
extern int ext4_write_inode(struct inode *, struct writeback_control *);
extern int ext4_setattr(struct dentry *, struct iattr *);
extern int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index c31b05f..3753a8a 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -1150,7 +1150,7 @@ struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
if (!ext4_test_bit(bit, bitmap_bh->b_data))
goto bad_orphan;

- inode = ext4_iget(sb, ino);
+ inode = ext4_iget(sb, ino, EXT4_IGET_NORMAL);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
ext4_error(sb, "couldn't read orphan inode %lu (err %d)",
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index d1daac8d..00b2434 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4214,7 +4214,9 @@ static inline void ext4_iget_extra_inode(struct inode *inode,
EXT4_I(inode)->i_inline_off = 0;
}

-struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
+struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
+ ext4_iget_flags flags, const char *function,
+ unsigned int line)
{
struct ext4_iloc iloc;
struct ext4_inode *raw_inode;
@@ -4227,6 +4229,18 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
uid_t i_uid;
gid_t i_gid;

+ if (((flags & EXT4_IGET_NORMAL) &&
+ (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)) ||
+ (ino < EXT4_ROOT_INO) ||
+ (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))) {
+ if (flags & EXT4_IGET_HANDLE)
+ return ERR_PTR(-ESTALE);
+ __ext4_error(sb, function, line,
+ "inode #%lu: comm %s: iget: illegal inode #",
+ ino, current->comm);
+ return ERR_PTR(-EFSCORRUPTED);
+ }
+
inode = iget_locked(sb, ino);
if (!inode)
return ERR_PTR(-ENOMEM);
@@ -4242,11 +4256,18 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
raw_inode = ext4_raw_inode(&iloc);

if ((ino == EXT4_ROOT_INO) && (raw_inode->i_links_count == 0)) {
- EXT4_ERROR_INODE(inode, "root inode unallocated");
+ ext4_error_inode(inode, function, line, 0,
+ "iget: root inode unallocated");
ret = -EFSCORRUPTED;
goto bad_inode;
}

+ if ((flags & EXT4_IGET_HANDLE) &&
+ (raw_inode->i_links_count == 0) && (raw_inode->i_mode == 0)) {
+ ret = -ESTALE;
+ goto bad_inode;
+ }
+
if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
@@ -4273,7 +4294,8 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
}

if (!ext4_inode_csum_verify(inode, raw_inode, ei)) {
- EXT4_ERROR_INODE(inode, "checksum invalid");
+ ext4_error_inode(inode, function, line, 0,
+ "iget: checksum invalid");
ret = -EFSBADCRC;
goto bad_inode;
}
@@ -4321,7 +4343,8 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
inode->i_size = ext4_isize(raw_inode);
if ((size = i_size_read(inode)) < 0) {
- EXT4_ERROR_INODE(inode, "bad i_size value: %lld", size);
+ ext4_error_inode(inode, function, line, 0,
+ "iget: bad i_size value: %lld", size);
ret = -EFSCORRUPTED;
goto bad_inode;
}
@@ -4404,7 +4427,8 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
ret = 0;
if (ei->i_file_acl &&
!ext4_data_block_valid(EXT4_SB(sb), ei->i_file_acl, 1)) {
- EXT4_ERROR_INODE(inode, "bad extended attribute block %llu",
+ ext4_error_inode(inode, function, line, 0,
+ "iget: bad extended attribute block %llu",
ei->i_file_acl);
ret = -EFSCORRUPTED;
goto bad_inode;
@@ -4459,7 +4483,8 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
make_bad_inode(inode);
} else {
ret = -EFSCORRUPTED;
- EXT4_ERROR_INODE(inode, "bogus i_mode (%o)", inode->i_mode);
+ ext4_error_inode(inode, function, line, 0,
+ "iget: bogus i_mode (%o)", inode->i_mode);
goto bad_inode;
}
brelse(iloc.bh);
@@ -4473,13 +4498,6 @@ bad_inode:
return ERR_PTR(ret);
}

-struct inode *ext4_iget_normal(struct super_block *sb, unsigned long ino)
-{
- if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
- return ERR_PTR(-EFSCORRUPTED);
- return ext4_iget(sb, ino);
-}
-
static int ext4_inode_blocks_set(handle_t *handle,
struct ext4_inode *raw_inode,
struct ext4_inode_info *ei)
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index b02f210..d4addcc 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -105,7 +105,7 @@ static long swap_inode_boot_loader(struct super_block *sb,
if (!inode_owner_or_capable(inode) || !capable(CAP_SYS_ADMIN))
return -EPERM;

- inode_bl = ext4_iget(sb, EXT4_BOOT_LOADER_INO);
+ inode_bl = ext4_iget(sb, EXT4_BOOT_LOADER_INO, EXT4_IGET_SPECIAL);
if (IS_ERR(inode_bl))
return PTR_ERR(inode_bl);
ei_bl = EXT4_I(inode_bl);
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 49e0d97..566a8b0 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1601,7 +1601,7 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi
dentry);
return ERR_PTR(-EFSCORRUPTED);
}
- inode = ext4_iget_normal(dir->i_sb, ino);
+ inode = ext4_iget(dir->i_sb, ino, EXT4_IGET_NORMAL);
if (inode == ERR_PTR(-ESTALE)) {
EXT4_ERROR_INODE(dir,
"deleted inode referenced: %u",
@@ -1646,7 +1646,7 @@ struct dentry *ext4_get_parent(struct dentry *child)
return ERR_PTR(-EFSCORRUPTED);
}

- return d_obtain_alias(ext4_iget_normal(d_inode(child)->i_sb, ino));
+ return d_obtain_alias(ext4_iget(d_inode(child)->i_sb, ino, EXT4_IGET_NORMAL));
}

/*
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index f5b6667..7ed01bc 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1649,7 +1649,7 @@ int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
"No reserved GDT blocks, can't resize");
return -EPERM;
}
- inode = ext4_iget(sb, EXT4_RESIZE_INO);
+ inode = ext4_iget(sb, EXT4_RESIZE_INO, EXT4_IGET_SPECIAL);
if (IS_ERR(inode)) {
ext4_warning(sb, "Error opening resize inode");
return PTR_ERR(inode);
@@ -1977,7 +1977,8 @@ retry:
}

if (!resize_inode)
- resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
+ resize_inode = ext4_iget(sb, EXT4_RESIZE_INO,
+ EXT4_IGET_SPECIAL);
if (IS_ERR(resize_inode)) {
ext4_warning(sb, "Error opening resize inode");
return PTR_ERR(resize_inode);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index f2e0220..3653eb7 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1021,20 +1021,11 @@ static struct inode *ext4_nfs_get_inode(struct super_block *sb,
{
struct inode *inode;

- if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
- return ERR_PTR(-ESTALE);
- if (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
- return ERR_PTR(-ESTALE);
-
- /* iget isn't really right if the inode is currently unallocated!!
- *
- * ext4_read_inode will return a bad_inode if the inode had been
- * deleted, so we should be safe.
- *
+ /*
* Currently we don't know the generation for parent directory, so
* a generation of 0 means "accept any"
*/
- inode = ext4_iget_normal(sb, ino);
+ inode = ext4_iget(sb, ino, EXT4_IGET_HANDLE);
if (IS_ERR(inode))
return ERR_CAST(inode);
if (generation && inode->i_generation != generation) {
@@ -4035,7 +4026,7 @@ no_journal:
* so we can safely mount the rest of the filesystem now.
*/

- root = ext4_iget(sb, EXT4_ROOT_INO);
+ root = ext4_iget(sb, EXT4_ROOT_INO, EXT4_IGET_SPECIAL);
if (IS_ERR(root)) {
ext4_msg(sb, KERN_ERR, "get root inode failed");
ret = PTR_ERR(root);
@@ -4272,11 +4263,12 @@ static journal_t *ext4_get_journal(struct super_block *sb,

BUG_ON(!ext4_has_feature_journal(sb));

- /* First, test for the existence of a valid inode on disk. Bad
- * things happen if we iget() an unused inode, as the subsequent
- * iput() will try to delete it. */
-
- journal_inode = ext4_iget(sb, journal_inum);
+ /*
+ * Test for the existence of a valid inode on disk. Bad things
+ * happen if we iget() an unused inode, as the subsequent iput()
+ * will try to delete it.
+ */
+ journal_inode = ext4_iget(sb, journal_inum, EXT4_IGET_SPECIAL);
if (IS_ERR(journal_inode)) {
ext4_msg(sb, KERN_ERR, "no journal found");
return NULL;
@@ -5240,7 +5232,7 @@ static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
if (!qf_inums[type])
return -EPERM;

- qf_inode = ext4_iget(sb, qf_inums[type]);
+ qf_inode = ext4_iget(sb, qf_inums[type], EXT4_IGET_SPECIAL);
if (IS_ERR(qf_inode)) {
ext4_error(sb, "Bad quota inode # %lu", qf_inums[type]);
return PTR_ERR(qf_inode);
--
2.7.4