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Add fixes for ext4 security issues relating to corrupted disk images

This commit is contained in:
Ben Hutchings 2018-07-02 21:34:14 +01:00
parent f0d3d32b75
commit 2e3f7d9495
13 changed files with 731 additions and 0 deletions
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18
debian/changelog vendored
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@ -89,6 +89,24 @@ linux (4.17.3-1) UNRELEASED; urgency=medium
* dm: Enable DM_INTEGRITY as module (except on armel) (Closes: #896649)
* debian/lib/python/debian_linux/debian.py: Accept arbitrary revision
suffixes (Closes: #898087)
* ext4: add corruption check in ext4_xattr_set_entry() (CVE-2018-10879)
* ext4: always verify the magic number in xattr blocks (CVE-2018-10879)
* ext4: always check block group bounds in ext4_init_block_bitmap()
(CVE-2018-10878)
* ext4: make sure bitmaps and the inode table don't overlap with bg
descriptors (CVE-2018-10878)
* ext4: only look at the bg_flags field if it is valid (CVE-2018-10876)
* ext4: verify the depth of extent tree in ext4_find_extent()
(CVE-2018-10877)
* ext4: clear i_data in ext4_inode_info when removing inline data
(CVE-2018-10881)
* ext4: never move the system.data xattr out of the inode body
(CVE-2018-10880)
* jbd2: don't mark block as modified if the handle is out of credits
(CVE-2018-10883)
* ext4: avoid running out of journal credits when appending to an inline file
(CVE-2018-10883)
* ext4: add more inode number paranoia checks (CVE-2018-10882)
[ Romain Perier ]
* [x86] amdgpu: Enable DCN 1.0 Raven family (Closes: #901349)

48
debian/patches/bugfix/all/ext4-add-corruption-check-in-ext4_xattr_set_entry.patch vendored Normal file
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@ -0,0 +1,48 @@
From: Theodore Ts'o <tytso@mit.edu>
Date: Wed, 13 Jun 2018 00:23:11 -0400
Subject: ext4: add corruption check in ext4_xattr_set_entry()
Origin: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git/commit?id=4fda60bbdbb61de76e3d3c48ed77c9e9b96b00d1
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2018-10879
In theory this should have been caught earlier when the xattr list was
verified, but in case it got missed, it's simple enough to add check
to make sure we don't overrun the xattr buffer.
This addresses CVE-2018-10879.
https://bugzilla.kernel.org/show_bug.cgi?id=200001
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
---
fs/ext4/xattr.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index fc4ced59c565..230ba79715f6 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1560,7 +1560,7 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
handle_t *handle, struct inode *inode,
bool is_block)
{
- struct ext4_xattr_entry *last;
+ struct ext4_xattr_entry *last, *next;
struct ext4_xattr_entry *here = s->here;
size_t min_offs = s->end - s->base, name_len = strlen(i->name);
int in_inode = i->in_inode;
@@ -1595,7 +1595,13 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
/* Compute min_offs and last. */
last = s->first;
- for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
+ for (; !IS_LAST_ENTRY(last); last = next) {
+ next = EXT4_XATTR_NEXT(last);
+ if ((void *)next >= s->end) {
+ EXT4_ERROR_INODE(inode, "corrupted xattr entries");
+ ret = -EFSCORRUPTED;
+ goto out;
+ }
if (!last->e_value_inum && last->e_value_size) {
size_t offs = le16_to_cpu(last->e_value_offs);
if (offs < min_offs)

63
debian/patches/bugfix/all/ext4-add-more-inode-number-paranoia-checks.patch vendored Normal file
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@ -0,0 +1,63 @@
From: Theodore Ts'o <tytso@mit.edu>
Date: Sun, 17 Jun 2018 00:41:14 -0400
Subject: ext4: add more inode number paranoia checks
Origin: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git/commit?id=a0b4bd6c4418a8d2ba51f27968f5af005e5dbbdd
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2018-10882
If there is a directory entry pointing to a system inode (such as a
journal inode), complain and declare the file system to be corrupted.
Also, if the superblock's first inode number field is too small,
refuse to mount the file system.
This addresses CVE-2018-10882.
https://bugzilla.kernel.org/show_bug.cgi?id=200069
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
fs/ext4/ext4.h | 5 -----
fs/ext4/inode.c | 3 ++-
fs/ext4/super.c | 5 +++++
3 files changed, 7 insertions(+), 6 deletions(-)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1501,11 +1501,6 @@ static inline struct ext4_inode_info *EX
static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)
{
return ino == EXT4_ROOT_INO ||
- ino == EXT4_USR_QUOTA_INO ||
- ino == EXT4_GRP_QUOTA_INO ||
- ino == EXT4_BOOT_LOADER_INO ||
- ino == EXT4_JOURNAL_INO ||
- ino == EXT4_RESIZE_INO ||
(ino >= EXT4_FIRST_INO(sb) &&
ino <= le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count));
}
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4506,7 +4506,8 @@ static int __ext4_get_inode_loc(struct i
int inodes_per_block, inode_offset;
iloc->bh = NULL;
- if (!ext4_valid_inum(sb, inode->i_ino))
+ if (inode->i_ino < EXT4_ROOT_INO ||
+ inode->i_ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
return -EFSCORRUPTED;
iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3817,6 +3817,11 @@ static int ext4_fill_super(struct super_
} else {
sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
+ if (sbi->s_first_ino < EXT4_GOOD_OLD_FIRST_INO) {
+ ext4_msg(sb, KERN_ERR, "invalid first ino: %u",
+ sbi->s_first_ino);
+ goto failed_mount;
+ }
if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
(!is_power_of_2(sbi->s_inode_size)) ||
(sbi->s_inode_size > blocksize)) {

54
debian/patches/bugfix/all/ext4-always-check-block-group-bounds-in-ext4_init_bl.patch vendored Normal file
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@ -0,0 +1,54 @@
From: Theodore Ts'o <tytso@mit.edu>
Date: Wed, 13 Jun 2018 23:00:48 -0400
Subject: ext4: always check block group bounds in ext4_init_block_bitmap()
Origin: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git/commit?id=dcf37fefac3f699aa1341f86bcd7808ccc651c33
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2018-10878
Regardless of whether the flex_bg feature is set, we should always
check to make sure the bits we are setting in the block bitmap are
within the block group bounds.
https://bugzilla.kernel.org/show_bug.cgi?id=199865
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[bwh: Backported to 4.17: adjust context]
---
fs/ext4/balloc.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -184,7 +184,6 @@ static int ext4_init_block_bitmap(struct
unsigned int bit, bit_max;
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_fsblk_t start, tmp;
- int flex_bg = 0;
struct ext4_group_info *grp;
J_ASSERT_BH(bh, buffer_locked(bh));
@@ -217,22 +216,19 @@ static int ext4_init_block_bitmap(struct
start = ext4_group_first_block_no(sb, block_group);
- if (ext4_has_feature_flex_bg(sb))
- flex_bg = 1;
-
/* Set bits for block and inode bitmaps, and inode table */
tmp = ext4_block_bitmap(sb, gdp);
- if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
+ if (ext4_block_in_group(sb, tmp, block_group))
ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
tmp = ext4_inode_bitmap(sb, gdp);
- if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
+ if (ext4_block_in_group(sb, tmp, block_group))
ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
tmp = ext4_inode_table(sb, gdp);
for (; tmp < ext4_inode_table(sb, gdp) +
sbi->s_itb_per_group; tmp++) {
- if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
+ if (ext4_block_in_group(sb, tmp, block_group))
ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
}

45
debian/patches/bugfix/all/ext4-always-verify-the-magic-number-in-xattr-blocks.patch vendored Normal file
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@ -0,0 +1,45 @@
From: Theodore Ts'o <tytso@mit.edu>
Date: Wed, 13 Jun 2018 00:51:28 -0400
Subject: ext4: always verify the magic number in xattr blocks
Origin: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git/commit?id=3345c50533c6a17ebc0284362ca7b69aaef37ac4
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2018-10879
If there an inode points to a block which is also some other type of
metadata block (such as a block allocation bitmap), the
buffer_verified flag can be set when it was validated as that other
metadata block type; however, it would make a really terrible external
attribute block. The reason why we use the verified flag is to avoid
constantly reverifying the block. However, it doesn't take much
overhead to make sure the magic number of the xattr block is correct,
and this will avoid potential crashes.
This addresses CVE-2018-10879.
https://bugzilla.kernel.org/show_bug.cgi?id=200001
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
---
fs/ext4/xattr.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 230ba79715f6..0263692979ec 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -230,12 +230,12 @@ __ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh,
{
int error = -EFSCORRUPTED;
- if (buffer_verified(bh))
- return 0;
-
if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
BHDR(bh)->h_blocks != cpu_to_le32(1))
goto errout;
+ if (buffer_verified(bh))
+ return 0;
+
error = -EFSBADCRC;
if (!ext4_xattr_block_csum_verify(inode, bh))
goto errout;

120
debian/patches/bugfix/all/ext4-avoid-running-out-of-journal-credits-when-appen.patch vendored Normal file
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@ -0,0 +1,120 @@
From: Theodore Ts'o <tytso@mit.edu>
Date: Sat, 16 Jun 2018 23:41:59 -0400
Subject: ext4: avoid running out of journal credits when appending to an
inline file
Origin: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git/commit?id=3886651521995071fab29401094e675b6ebfdc8c
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2018-10883
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@mit.edu>
---
fs/ext4/ext4.h | 3 ---
fs/ext4/inline.c | 38 +-------------------------------------
fs/ext4/xattr.c | 19 ++-----------------
3 files changed, 3 insertions(+), 57 deletions(-)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3005,9 +3005,6 @@ extern int ext4_inline_data_fiemap(struc
struct iomap;
extern int ext4_inline_data_iomap(struct inode *inode, struct iomap *iomap);
-extern int ext4_try_to_evict_inline_data(handle_t *handle,
- struct inode *inode,
- int needed);
extern int 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
@@ -887,11 +887,11 @@ retry_journal:
flags |= AOP_FLAG_NOFS;
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;
@@ -1891,42 +1891,6 @@ 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;
-}
-
int ext4_inline_data_truncate(struct inode *inode, int *has_inline)
{
handle_t *handle;
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -2212,23 +2212,8 @@ 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, handle, inode, false /* is_block */);
- 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, handle, inode,
- false /* is_block */);
- }
- 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);

42
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@ -0,0 +1,42 @@
From: Theodore Ts'o <tytso@mit.edu>
Date: Fri, 15 Jun 2018 12:28:16 -0400
Subject: ext4: clear i_data in ext4_inode_info when removing inline data
Origin: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git/commit?id=cd75e020ee28aa21985c6d8ebafc7457b4c51531
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2018-10881
When converting from an inode from storing the data in-line to a data
block, ext4_destroy_inline_data_nolock() was only clearing the on-disk
copy of the i_blocks[] array. It was not clearing copy of the
i_blocks[] in ext4_inode_info, in i_data[], which is the copy actually
used by ext4_map_blocks().
This didn't matter much if we are using extents, since the extents
header would be invalid and thus the extents could would re-initialize
the extents tree. But if we are using indirect blocks, the previous
contents of the i_blocks array will be treated as block numbers, with
potentially catastrophic results to the file system integrity and/or
user data.
This gets worse if the file system is using a 1k block size and
s_first_data is zero, but even without this, the file system can get
quite badly corrupted.
This addresses CVE-2018-10881.
https://bugzilla.kernel.org/show_bug.cgi?id=200015
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
fs/ext4/inline.c | 1 +
1 file changed, 1 insertion(+)
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -437,6 +437,7 @@ static int ext4_destroy_inline_data_nolo
memset((void *)ext4_raw_inode(&is.iloc)->i_block,
0, EXT4_MIN_INLINE_DATA_SIZE);
+ memset(ei->i_data, 0, EXT4_MIN_INLINE_DATA_SIZE);
if (ext4_has_feature_extents(inode->i_sb)) {
if (S_ISDIR(inode->i_mode) ||

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debian/patches/bugfix/all/ext4-make-sure-bitmaps-and-the-inode-table-don-t-ove.patch vendored Normal file
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@ -0,0 +1,74 @@
From: Theodore Ts'o <tytso@mit.edu>
Date: Wed, 13 Jun 2018 23:08:26 -0400
Subject: ext4: make sure bitmaps and the inode table don't overlap with bg
descriptors
Origin: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git/commit?id=6b506a7d09854128b1da9571d879ee9dea3ffb02
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2018-10878
It's really bad when the allocation bitmaps and the inode table
overlap with the block group descriptors, since it causes random
corruption of the bg descriptors. So we really want to head those off
at the pass.
https://bugzilla.kernel.org/show_bug.cgi?id=199865
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
fs/ext4/super.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2307,6 +2307,7 @@ static int ext4_check_descriptors(struct
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
ext4_fsblk_t last_block;
+ ext4_fsblk_t last_bg_block = sb_block + ext4_bg_num_gdb(sb, 0) + 1;
ext4_fsblk_t block_bitmap;
ext4_fsblk_t inode_bitmap;
ext4_fsblk_t inode_table;
@@ -2339,6 +2340,14 @@ static int ext4_check_descriptors(struct
if (!sb_rdonly(sb))
return 0;
}
+ if (block_bitmap >= sb_block + 1 &&
+ block_bitmap <= last_bg_block) {
+ ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
+ "Block bitmap for group %u overlaps "
+ "block group descriptors", i);
+ if (!sb_rdonly(sb))
+ return 0;
+ }
if (block_bitmap < first_block || block_bitmap > last_block) {
ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
"Block bitmap for group %u not in group "
@@ -2353,6 +2362,14 @@ static int ext4_check_descriptors(struct
if (!sb_rdonly(sb))
return 0;
}
+ if (inode_bitmap >= sb_block + 1 &&
+ inode_bitmap <= last_bg_block) {
+ ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
+ "Inode bitmap for group %u overlaps "
+ "block group descriptors", i);
+ if (!sb_rdonly(sb))
+ return 0;
+ }
if (inode_bitmap < first_block || inode_bitmap > last_block) {
ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
"Inode bitmap for group %u not in group "
@@ -2367,6 +2384,14 @@ static int ext4_check_descriptors(struct
if (!sb_rdonly(sb))
return 0;
}
+ if (inode_table >= sb_block + 1 &&
+ inode_table <= last_bg_block) {
+ ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
+ "Inode table for group %u overlaps "
+ "block group descriptors", i);
+ if (!sb_rdonly(sb))
+ return 0;
+ }
if (inode_table < first_block ||
inode_table + sbi->s_itb_per_group - 1 > last_block) {
ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "

34
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@ -0,0 +1,34 @@
From: Theodore Ts'o <tytso@mit.edu>
Date: Sat, 16 Jun 2018 15:40:48 -0400
Subject: ext4: never move the system.data xattr out of the inode body
Origin: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git/commit?id=896003d9fd652666080a06411d4238ee6eb4fb76
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2018-10880
When expanding the extra isize space, we must never move the
system.data xattr out of the inode body. For performance reasons, it
doesn't make any sense, and the inline data implementation assumes
that system.data xattr is never in the external xattr block.
This addresses CVE-2018-10880
https://bugzilla.kernel.org/show_bug.cgi?id=200005
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
fs/ext4/xattr.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -2657,6 +2657,11 @@ static int ext4_xattr_make_inode_space(h
last = IFIRST(header);
/* Find the entry best suited to be pushed into EA block */
for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
+ /* never move system.data out of the inode */
+ if ((last->e_name_len == 4) &&
+ (last->e_name_index == EXT4_XATTR_INDEX_SYSTEM) &&
+ !memcmp(last->e_name, "data", 4))
+ continue;
total_size = EXT4_XATTR_LEN(last->e_name_len);
if (!last->e_value_inum)
total_size += EXT4_XATTR_SIZE(

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debian/patches/bugfix/all/ext4-only-look-at-the-bg_flags-field-if-it-is-valid.patch vendored Normal file
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@ -0,0 +1,125 @@
From: Theodore Ts'o <tytso@mit.edu>
Date: Thu, 14 Jun 2018 00:58:00 -0400
Subject: ext4: only look at the bg_flags field if it is valid
Origin: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git/commit?id=32a82d31527ae9cb568f5d7fa5ad27b2860324ed
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2018-10876
The bg_flags field in the block group descripts is only valid if the
uninit_bg or metadata_csum feature is enabled. We were not
consistently looking at this field; fix this.
Also block group #0 must never have uninitialized allocation bitmaps,
or need to be zeroed, since that's where the root inode, and other
special inodes are set up. Check for these conditions and mark the
file system as corrupted if they are detected.
This addresses CVE-2018-10876.
https://bugzilla.kernel.org/show_bug.cgi?id=199403
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
fs/ext4/balloc.c | 11 ++++++++++-
fs/ext4/ialloc.c | 14 ++++++++++++--
fs/ext4/mballoc.c | 6 ++++--
fs/ext4/super.c | 11 ++++++++++-
4 files changed, 36 insertions(+), 6 deletions(-)
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -451,7 +451,16 @@ ext4_read_block_bitmap_nowait(struct sup
goto verify;
}
ext4_lock_group(sb, block_group);
- if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
+ if (ext4_has_group_desc_csum(sb) &&
+ (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
+ if (block_group == 0) {
+ ext4_unlock_group(sb, block_group);
+ unlock_buffer(bh);
+ ext4_error(sb, "Block bitmap for bg 0 marked "
+ "uninitialized");
+ err = -EFSCORRUPTED;
+ goto out;
+ }
err = ext4_init_block_bitmap(sb, bh, block_group, desc);
set_bitmap_uptodate(bh);
set_buffer_uptodate(bh);
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -155,7 +155,16 @@ ext4_read_inode_bitmap(struct super_bloc
}
ext4_lock_group(sb, block_group);
- if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
+ if (ext4_has_group_desc_csum(sb) &&
+ (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT))) {
+ if (block_group == 0) {
+ ext4_unlock_group(sb, block_group);
+ unlock_buffer(bh);
+ ext4_error(sb, "Inode bitmap for bg 0 marked "
+ "uninitialized");
+ err = -EFSCORRUPTED;
+ goto out;
+ }
memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
sb->s_blocksize * 8, bh->b_data);
@@ -1000,7 +1009,8 @@ got:
/* recheck and clear flag under lock if we still need to */
ext4_lock_group(sb, group);
- if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
+ if (ext4_has_group_desc_csum(sb) &&
+ (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
ext4_free_group_clusters_set(sb, gdp,
ext4_free_clusters_after_init(sb, group, gdp));
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2444,7 +2444,8 @@ int ext4_mb_add_groupinfo(struct super_b
* initialize bb_free to be able to skip
* empty groups without initialization
*/
- if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
+ if (ext4_has_group_desc_csum(sb) &&
+ (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
meta_group_info[i]->bb_free =
ext4_free_clusters_after_init(sb, group, desc);
} else {
@@ -3011,7 +3012,8 @@ ext4_mb_mark_diskspace_used(struct ext4_
#endif
ext4_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
ac->ac_b_ex.fe_len);
- if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
+ if (ext4_has_group_desc_csum(sb) &&
+ (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
ext4_free_group_clusters_set(sb, gdp,
ext4_free_clusters_after_init(sb,
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3098,13 +3098,22 @@ static ext4_group_t ext4_has_uninit_itab
ext4_group_t group, ngroups = EXT4_SB(sb)->s_groups_count;
struct ext4_group_desc *gdp = NULL;
+ if (!ext4_has_group_desc_csum(sb))
+ return ngroups;
+
for (group = 0; group < ngroups; group++) {
gdp = ext4_get_group_desc(sb, group, NULL);
if (!gdp)
continue;
- if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
+ if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED))
+ continue;
+ if (group != 0)
break;
+ ext4_error(sb, "Inode table for bg 0 marked as "
+ "needing zeroing");
+ if (sb_rdonly(sb))
+ return ngroups;
}
return group;

45
debian/patches/bugfix/all/ext4-verify-the-depth-of-extent-tree-in-ext4_find_ex.patch vendored Normal file
View File

@ -0,0 +1,45 @@
From: Theodore Ts'o <tytso@mit.edu>
Date: Thu, 14 Jun 2018 12:55:10 -0400
Subject: ext4: verify the depth of extent tree in ext4_find_extent()
Origin: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git/commit?id=0a8173832987f52ab6926dbdf1cd3991ca615000
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2018-10877
If there is a corupted file system where the claimed depth of the
extent tree is -1, this can cause a massive buffer overrun leading to
sadness.
This addresses CVE-2018-10877.
https://bugzilla.kernel.org/show_bug.cgi?id=199417
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
fs/ext4/ext4_extents.h | 1 +
fs/ext4/extents.c | 6 ++++++
2 files changed, 7 insertions(+)
--- a/fs/ext4/ext4_extents.h
+++ b/fs/ext4/ext4_extents.h
@@ -91,6 +91,7 @@ struct ext4_extent_header {
};
#define EXT4_EXT_MAGIC cpu_to_le16(0xf30a)
+#define EXT4_MAX_EXTENT_DEPTH 5
#define EXT4_EXTENT_TAIL_OFFSET(hdr) \
(sizeof(struct ext4_extent_header) + \
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -869,6 +869,12 @@ ext4_find_extent(struct inode *inode, ex
eh = ext_inode_hdr(inode);
depth = ext_depth(inode);
+ if (depth < 0 || depth > EXT4_MAX_EXTENT_DEPTH) {
+ EXT4_ERROR_INODE(inode, "inode has invalid extent depth: %d",
+ depth);
+ ret = -EFSCORRUPTED;
+ goto err;
+ }
if (path) {
ext4_ext_drop_refs(path);

52
debian/patches/bugfix/all/jbd2-don-t-mark-block-as-modified-if-the-handle-is-o.patch vendored Normal file
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@ -0,0 +1,52 @@
From: Theodore Ts'o <tytso@mit.edu>
Date: Sat, 16 Jun 2018 20:21:45 -0400
Subject: jbd2: don't mark block as modified if the handle is out of credits
Origin: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git/commit?id=aa18d2cefac6c34885659d12c3fdcffcd6c54e9a
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2018-10883
Do not set the b_modified flag in block's journal head should not
until after we're sure that jbd2_journal_dirty_metadat() will not
abort with an error due to there not being enough space reserved in
the jbd2 handle.
Otherwise, future attempts to modify the buffer may lead a large
number of spurious errors and warnings.
This addresses CVE-2018-10883.
https://bugzilla.kernel.org/show_bug.cgi?id=200071
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
fs/jbd2/transaction.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1363,6 +1363,13 @@ int jbd2_journal_dirty_metadata(handle_t
if (jh->b_transaction == transaction &&
jh->b_jlist != BJ_Metadata) {
jbd_lock_bh_state(bh);
+ if (jh->b_transaction == transaction &&
+ jh->b_jlist != BJ_Metadata)
+ pr_err("JBD2: assertion failure: h_type=%u "
+ "h_line_no=%u block_no=%llu jlist=%u\n",
+ handle->h_type, handle->h_line_no,
+ (unsigned long long) bh->b_blocknr,
+ jh->b_jlist);
J_ASSERT_JH(jh, jh->b_transaction != transaction ||
jh->b_jlist == BJ_Metadata);
jbd_unlock_bh_state(bh);
@@ -1382,11 +1389,11 @@ int jbd2_journal_dirty_metadata(handle_t
* of the transaction. This needs to be done
* once a transaction -bzzz
*/
- jh->b_modified = 1;
if (handle->h_buffer_credits <= 0) {
ret = -ENOSPC;
goto out_unlock_bh;
}
+ jh->b_modified = 1;
handle->h_buffer_credits--;
}

11
debian/patches/series vendored
View File

@ -133,6 +133,17 @@ features/all/lockdown/arm64-add-kernel-config-option-to-lock-down-when.patch
debian/i386-686-pae-pci-set-pci-nobios-by-default.patch
bugfix/x86/virt-vbox-Only-copy_from_user-the-request-header-onc.patch
bugfix/all/tracing-check-for-no-filter-when-processing-event-fi.patch
bugfix/all/ext4-add-corruption-check-in-ext4_xattr_set_entry.patch
bugfix/all/ext4-always-verify-the-magic-number-in-xattr-blocks.patch
bugfix/all/ext4-always-check-block-group-bounds-in-ext4_init_bl.patch
bugfix/all/ext4-make-sure-bitmaps-and-the-inode-table-don-t-ove.patch
bugfix/all/ext4-only-look-at-the-bg_flags-field-if-it-is-valid.patch
bugfix/all/ext4-verify-the-depth-of-extent-tree-in-ext4_find_ex.patch
bugfix/all/ext4-clear-i_data-in-ext4_inode_info-when-removing-i.patch
bugfix/all/ext4-never-move-the-system.data-xattr-out-of-the-ino.patch
bugfix/all/jbd2-don-t-mark-block-as-modified-if-the-handle-is-o.patch
bugfix/all/ext4-avoid-running-out-of-journal-credits-when-appen.patch
bugfix/all/ext4-add-more-inode-number-paranoia-checks.patch
# Fix exported symbol versions
bugfix/all/module-disable-matching-missing-version-crc.patch