2020-04-29 20:34:09

by ashwin-h

[permalink] [raw]
Subject: [PATCH 0/5] Backport to 4.14 - 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 4.14

[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 | 53 +++++++++++++++++++++++++++++++++--------------
fs/ext4/ioctl.c | 2 +-
fs/ext4/namei.c | 4 ++--
fs/ext4/resize.c | 5 +++--
fs/ext4/super.c | 19 +++++------------
fs/ext4/xattr.c | 5 +++--
10 files changed, 128 insertions(+), 43 deletions(-)

--
2.7.4


2020-04-29 20:34:09

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 | 49 ++++++++++++++++++++++++++++++++++---------------
fs/ext4/ioctl.c | 2 +-
fs/ext4/namei.c | 4 ++--
fs/ext4/resize.c | 5 +++--
fs/ext4/super.c | 19 +++++--------------
fs/ext4/xattr.c | 5 +++--
8 files changed, 62 insertions(+), 39 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 4aa0f8f..6c5b430 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2509,8 +2509,19 @@ 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(const struct path *, struct kstat *, u32, unsigned int);
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 2a480c0..2daef32 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -1239,7 +1239,7 @@ 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 5b0d5ca..07476c1 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4695,7 +4695,9 @@ int ext4_get_projid(struct inode *inode, kprojid_t *projid)
return 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;
@@ -4709,6 +4711,18 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
gid_t i_gid;
projid_t i_projid;

+ 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);
@@ -4724,18 +4738,26 @@ 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 >
EXT4_INODE_SIZE(inode->i_sb) ||
(ei->i_extra_isize & 3)) {
- EXT4_ERROR_INODE(inode,
- "bad extra_isize %u (inode size %u)",
+ ext4_error_inode(inode, function, line, 0,
+ "iget: bad extra_isize %u "
+ "(inode size %u)",
ei->i_extra_isize,
EXT4_INODE_SIZE(inode->i_sb));
ret = -EFSCORRUPTED;
@@ -4757,7 +4779,8 @@ 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;
}
@@ -4813,7 +4836,8 @@ 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(sb, 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;
}
@@ -4899,7 +4923,8 @@ 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;
@@ -4954,7 +4979,8 @@ 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);
@@ -4969,13 +4995,6 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
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 82e118e..9dbb554 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -111,7 +111,7 @@ 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 3f7b383..161099f 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1597,7 +1597,7 @@ 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",
@@ -1639,7 +1639,7 @@ struct dentry *ext4_get_parent(struct dentry *child)
return ERR_PTR(-EFSCORRUPTED);
}

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

/*
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index d42f747..19af346 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1652,7 +1652,7 @@ 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);
@@ -1980,7 +1980,8 @@ int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
}

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 0ced133..086fcbe 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1126,20 +1126,11 @@ 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) {
@@ -4370,7 +4361,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
* 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);
@@ -4620,7 +4611,7 @@ static struct inode *ext4_get_journal_inode(struct super_block *sb,
* happen if we iget() an unused inode, as the subsequent iput()
* will try to delete it.
*/
- journal_inode = ext4_iget(sb, journal_inum);
+ 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;
@@ -5693,7 +5684,7 @@ 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);
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index f2fde3ac..b0873b8 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -383,7 +383,7 @@ static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
struct inode *inode;
int err;

- inode = ext4_iget(parent->i_sb, ea_ino);
+ inode = ext4_iget(parent->i_sb, ea_ino, EXT4_IGET_NORMAL);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
ext4_error(parent->i_sb,
@@ -1486,7 +1486,8 @@ ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
}

while (ce) {
- ea_inode = ext4_iget(inode->i_sb, ce->e_value);
+ 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) &&
--
2.7.4

2020-04-29 20:34:12

by ashwin-h

[permalink] [raw]
Subject: [PATCH 2/5] ext4: protect journal inode's blocks using block_validity

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

commit 345c0dbf3a30872d9b204db96b5857cd00808cae upstream.

Add the blocks which belong to the journal inode to block_validity's
system zone so attempts to deallocate or overwrite the journal due a
corrupted file system where the journal blocks are also claimed by
another inode.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202879
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Ashwin H <[email protected]>
Cc: [email protected]
---
fs/ext4/block_validity.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
fs/ext4/inode.c | 4 ++++
2 files changed, 52 insertions(+)

diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c
index bee888e..2370dfd 100644
--- a/fs/ext4/block_validity.c
+++ b/fs/ext4/block_validity.c
@@ -137,6 +137,48 @@ static void debug_print_tree(struct ext4_sb_info *sbi)
printk(KERN_CONT "\n");
}

+static int ext4_protect_reserved_inode(struct super_block *sb, u32 ino)
+{
+ struct inode *inode;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct ext4_map_blocks map;
+ u32 i = 0, err = 0, num, n;
+
+ if ((ino < EXT4_ROOT_INO) ||
+ (ino > le32_to_cpu(sbi->s_es->s_inodes_count)))
+ return -EINVAL;
+ inode = ext4_iget(sb, ino, EXT4_IGET_SPECIAL);
+ if (IS_ERR(inode))
+ return PTR_ERR(inode);
+ num = (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
+ while (i < num) {
+ map.m_lblk = i;
+ map.m_len = num - i;
+ n = ext4_map_blocks(NULL, inode, &map, 0);
+ if (n < 0) {
+ err = n;
+ break;
+ }
+ if (n == 0) {
+ i++;
+ } else {
+ if (!ext4_data_block_valid(sbi, map.m_pblk, n)) {
+ ext4_error(sb, "blocks %llu-%llu from inode %u "
+ "overlap system zone", map.m_pblk,
+ map.m_pblk + map.m_len - 1, ino);
+ err = -EFSCORRUPTED;
+ break;
+ }
+ err = add_system_zone(sbi, map.m_pblk, n);
+ if (err < 0)
+ break;
+ i += n;
+ }
+ }
+ iput(inode);
+ return err;
+}
+
int ext4_setup_system_zone(struct super_block *sb)
{
ext4_group_t ngroups = ext4_get_groups_count(sb);
@@ -171,6 +213,12 @@ int ext4_setup_system_zone(struct super_block *sb)
if (ret)
return ret;
}
+ if (ext4_has_feature_journal(sb) && sbi->s_es->s_journal_inum) {
+ ret = ext4_protect_reserved_inode(sb,
+ le32_to_cpu(sbi->s_es->s_journal_inum));
+ if (ret)
+ return ret;
+ }

if (test_opt(sb, DEBUG))
debug_print_tree(EXT4_SB(sb));
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 07476c1..390431d 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -407,6 +407,10 @@ static int __check_block_validity(struct inode *inode, const char *func,
unsigned int line,
struct ext4_map_blocks *map)
{
+ 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;
if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), map->m_pblk,
map->m_len)) {
ext4_error_inode(inode, func, line, map->m_pblk,
--
2.7.4

2020-04-29 20:36:22

by ashwin-h

[permalink] [raw]
Subject: [PATCH 5/5] ext4: unsigned int compared against zero

From: Colin Ian King <[email protected]>

commit fbbbbd2f28aec991f3fbc248df211550fbdfd58c upstream.

There are two cases where u32 variables n and err are being checked
for less than zero error values, the checks is always false because
the variables are not signed. Fix this by making the variables ints.

Addresses-Coverity: ("Unsigned compared against 0")
Fixes: 345c0dbf3a30 ("ext4: protect journal inode's blocks using block_validity")
Signed-off-by: Colin Ian King <[email protected]>
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Ashwin H <[email protected]>
---
fs/ext4/block_validity.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c
index 7ba8920..13eb028 100644
--- a/fs/ext4/block_validity.c
+++ b/fs/ext4/block_validity.c
@@ -142,7 +142,8 @@ static int ext4_protect_reserved_inode(struct super_block *sb, u32 ino)
struct inode *inode;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_map_blocks map;
- u32 i = 0, err = 0, num, n;
+ u32 i = 0, num;
+ int err = 0, n;

if ((ino < EXT4_ROOT_INO) ||
(ino > le32_to_cpu(sbi->s_es->s_inodes_count)))
--
2.7.4