NAK: [SRU][F][PATCH 1/4] ext4: save the error code which triggered an ext4_error() in the superblock
Tim Gardner
tim.gardner at canonical.com
Fri Oct 8 12:32:28 UTC 2021
On 10/7/21 2:05 PM, Luke Nowakowski-Krijger wrote:
> From: Theodore Ts'o <tytso at mit.edu>
>
> This allows the cause of an ext4_error() report to be categorized
> based on whether it was triggered due to an I/O error, or an memory
> allocation error, or other possible causes. Most errors are caused by
> a detected file system inconsistency, so the default code stored in
> the superblock will be EXT4_ERR_EFSCORRUPTED.
>
> Link: https://lore.kernel.org/r/20191204032335.7683-1-tytso@mit.edu
> Signed-off-by: Theodore Ts'o <tytso at mit.edu>
> (backported from commit 878520ac45f9f698432d4276db3d9144b83931b6)
> [lukenow: updated minor context change to include sbi_array_rcu_deref
> define]
This isn't accurate. What you did was to add error number codes to
fs/ext4/ext4.h. sbi_array_rcu_deref() already existed. It was otherwise
a simple enough context adjustment.
> CVE-2021-3428
> Signed-off-by: Luke Nowakowski-Krijger <luke.nowakowskikrijger at canonical.com>
> ---
> fs/ext4/balloc.c | 1 +
> fs/ext4/ext4.h | 30 +++++++++++++++++++-
> fs/ext4/ext4_jbd2.c | 3 ++
> fs/ext4/extents.c | 1 +
> fs/ext4/ialloc.c | 2 ++
> fs/ext4/inline.c | 2 ++
> fs/ext4/inode.c | 8 +++++-
> fs/ext4/mballoc.c | 4 +++
> fs/ext4/mmp.c | 6 +++-
> fs/ext4/namei.c | 4 +++
> fs/ext4/super.c | 68 ++++++++++++++++++++++++++++++++++++++++++++-
> fs/ext4/xattr.c | 4 ++-
> 12 files changed, 128 insertions(+), 5 deletions(-)
>
> diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
> index 031ff3f19018..f6fee620e57d 100644
> --- a/fs/ext4/balloc.c
> +++ b/fs/ext4/balloc.c
> @@ -514,6 +514,7 @@ int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group,
> return -EFSCORRUPTED;
> wait_on_buffer(bh);
> if (!buffer_uptodate(bh)) {
> + ext4_set_errno(sb, EIO);
> ext4_error(sb, "Cannot read block bitmap - "
> "block_group = %u, block_bitmap = %llu",
> block_group, (unsigned long long) bh->b_blocknr);
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index ae2cb15d9540..68778d362467 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -1338,7 +1338,8 @@ struct ext4_super_block {
> __u8 s_lastcheck_hi;
> __u8 s_first_error_time_hi;
> __u8 s_last_error_time_hi;
> - __u8 s_pad[2];
> + __u8 s_first_error_errcode;
> + __u8 s_last_error_errcode;
> __le16 s_encoding; /* Filename charset encoding */
> __le16 s_encoding_flags; /* Filename charset encoding flags */
> __le32 s_reserved[95]; /* Padding to the end of the block */
> @@ -1590,6 +1591,32 @@ static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)
> _v; \
> })
>
> +/*
> + * Error number codes for s_{first,last}_error_errno
> + *
> + * Linux errno numbers are architecture specific, so we need to translate
> + * them into something which is architecture independent. We don't define
> + * codes for all errno's; just the ones which are most likely to be the cause
> + * of an ext4_error() call.
> + */
> +#define EXT4_ERR_UNKNOWN 1
> +#define EXT4_ERR_EIO 2
> +#define EXT4_ERR_ENOMEM 3
> +#define EXT4_ERR_EFSBADCRC 4
> +#define EXT4_ERR_EFSCORRUPTED 5
> +#define EXT4_ERR_ENOSPC 6
> +#define EXT4_ERR_ENOKEY 7
> +#define EXT4_ERR_EROFS 8
> +#define EXT4_ERR_EFBIG 9
> +#define EXT4_ERR_EEXIST 10
> +#define EXT4_ERR_ERANGE 11
> +#define EXT4_ERR_EOVERFLOW 12
> +#define EXT4_ERR_EBUSY 13
> +#define EXT4_ERR_ENOTDIR 14
> +#define EXT4_ERR_ENOTEMPTY 15
> +#define EXT4_ERR_ESHUTDOWN 16
> +#define EXT4_ERR_EFAULT 17
> +
> /*
> * Inode dynamic state flags
> */
> @@ -2711,6 +2738,7 @@ extern const char *ext4_decode_error(struct super_block *sb, int errno,
> extern void ext4_mark_group_bitmap_corrupted(struct super_block *sb,
> ext4_group_t block_group,
> unsigned int flags);
> +extern void ext4_set_errno(struct super_block *sb, int err);
>
> extern __printf(4, 5)
> void __ext4_error(struct super_block *, const char *, unsigned int,
> diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c
> index 7c70b08d104c..c48541cc7f78 100644
> --- a/fs/ext4/ext4_jbd2.c
> +++ b/fs/ext4/ext4_jbd2.c
> @@ -58,6 +58,7 @@ static int ext4_journal_check_start(struct super_block *sb)
> * take the FS itself readonly cleanly.
> */
> if (journal && is_journal_aborted(journal)) {
> + ext4_set_errno(sb, -journal->j_errno);
> ext4_abort(sb, "Detected aborted journal");
> return -EROFS;
> }
> @@ -234,6 +235,7 @@ int __ext4_forget(const char *where, unsigned int line, handle_t *handle,
> if (err) {
> ext4_journal_abort_handle(where, line, __func__,
> bh, handle, err);
> + ext4_set_errno(inode->i_sb, -err);
> __ext4_abort(inode->i_sb, where, line,
> "error %d when attempting revoke", err);
> }
> @@ -304,6 +306,7 @@ int __ext4_handle_dirty_metadata(const char *where, unsigned int line,
> es = EXT4_SB(inode->i_sb)->s_es;
> es->s_last_error_block =
> cpu_to_le64(bh->b_blocknr);
> + ext4_set_errno(inode->i_sb, EIO);
> ext4_error_inode(inode, where, line,
> bh->b_blocknr,
> "IO error syncing itable block");
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index ae73e6793683..486374d8f07b 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -480,6 +480,7 @@ static int __ext4_ext_check(const char *function, unsigned int line,
> return 0;
>
> corrupted:
> + ext4_set_errno(inode->i_sb, -err);
> ext4_error_inode(inode, function, line, 0,
> "pblk %llu bad header/extent: %s - magic %x, "
> "entries %u, max %u(%u), depth %u(%u)",
> diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
> index 83846cc81485..139fa1e9048a 100644
> --- a/fs/ext4/ialloc.c
> +++ b/fs/ext4/ialloc.c
> @@ -194,6 +194,7 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
> wait_on_buffer(bh);
> if (!buffer_uptodate(bh)) {
> put_bh(bh);
> + ext4_set_errno(sb, EIO);
> ext4_error(sb, "Cannot read inode bitmap - "
> "block_group = %u, inode_bitmap = %llu",
> block_group, bitmap_blk);
> @@ -1227,6 +1228,7 @@ struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
> inode = ext4_iget(sb, ino, EXT4_IGET_NORMAL);
> if (IS_ERR(inode)) {
> err = PTR_ERR(inode);
> + ext4_set_errno(sb, -err);
> ext4_error(sb, "couldn't read orphan inode %lu (err %d)",
> ino, err);
> return inode;
> diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
> index 46151bda6236..fcfe37783041 100644
> --- a/fs/ext4/inline.c
> +++ b/fs/ext4/inline.c
> @@ -98,6 +98,7 @@ int ext4_get_max_inline_size(struct inode *inode)
>
> error = ext4_get_inode_loc(inode, &iloc);
> if (error) {
> + ext4_set_errno(inode->i_sb, -error);
> ext4_error_inode(inode, __func__, __LINE__, 0,
> "can't get inode location %lu",
> inode->i_ino);
> @@ -1767,6 +1768,7 @@ bool empty_inline_dir(struct inode *dir, int *has_inline_data)
>
> err = ext4_get_inode_loc(dir, &iloc);
> if (err) {
> + ext4_set_errno(dir->i_sb, -err);
> EXT4_ERROR_INODE(dir, "error %d getting inode %lu block",
> err, dir->i_ino);
> return true;
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 4ff06480dcac..1d48cdd77fbb 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -304,6 +304,7 @@ void ext4_evict_inode(struct inode *inode)
> if (inode->i_blocks) {
> err = ext4_truncate(inode);
> if (err) {
> + ext4_set_errno(inode->i_sb, -err);
> ext4_error(inode->i_sb,
> "couldn't truncate inode %lu (err %d)",
> inode->i_ino, err);
> @@ -2597,10 +2598,12 @@ static int mpage_map_and_submit_extent(handle_t *handle,
> EXT4_I(inode)->i_disksize = disksize;
> up_write(&EXT4_I(inode)->i_data_sem);
> err2 = ext4_mark_inode_dirty(handle, inode);
> - if (err2)
> + if (err2) {
> + ext4_set_errno(inode->i_sb, -err2);
> ext4_error(inode->i_sb,
> "Failed to mark inode %lu dirty",
> inode->i_ino);
> + }
> if (!err)
> err = err2;
> }
> @@ -4712,6 +4715,7 @@ static int __ext4_get_inode_loc(struct inode *inode,
> blk_finish_plug(&plug);
> wait_on_buffer(bh);
> if (!buffer_uptodate(bh)) {
> + ext4_set_errno(inode->i_sb, EIO);
> EXT4_ERROR_INODE_BLOCK(inode, block,
> "unable to read itable block");
> brelse(bh);
> @@ -4926,6 +4930,7 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
> }
>
> if (!ext4_inode_csum_verify(inode, raw_inode, ei)) {
> + ext4_set_errno(inode->i_sb, EFSBADCRC);
> ext4_error_inode(inode, function, line, 0,
> "iget: checksum invalid");
> ret = -EFSBADCRC;
> @@ -5477,6 +5482,7 @@ int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
> if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync)
> sync_dirty_buffer(iloc.bh);
> if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
> + ext4_set_errno(inode->i_sb, EIO);
> EXT4_ERROR_INODE_BLOCK(inode, iloc.bh->b_blocknr,
> "IO error syncing inode");
> err = -EIO;
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index b67ea979f0cf..584a96634547 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -3924,6 +3924,7 @@ ext4_mb_discard_group_preallocations(struct super_block *sb,
> bitmap_bh = ext4_read_block_bitmap(sb, group);
> if (IS_ERR(bitmap_bh)) {
> err = PTR_ERR(bitmap_bh);
> + ext4_set_errno(sb, -err);
> ext4_error(sb, "Error %d reading block bitmap for %u",
> err, group);
> return 0;
> @@ -4092,6 +4093,7 @@ void ext4_discard_preallocations(struct inode *inode)
> err = ext4_mb_load_buddy_gfp(sb, group, &e4b,
> GFP_NOFS|__GFP_NOFAIL);
> if (err) {
> + ext4_set_errno(sb, -err);
> ext4_error(sb, "Error %d loading buddy information for %u",
> err, group);
> continue;
> @@ -4100,6 +4102,7 @@ void ext4_discard_preallocations(struct inode *inode)
> bitmap_bh = ext4_read_block_bitmap(sb, group);
> if (IS_ERR(bitmap_bh)) {
> err = PTR_ERR(bitmap_bh);
> + ext4_set_errno(sb, -err);
> ext4_error(sb, "Error %d reading block bitmap for %u",
> err, group);
> ext4_mb_unload_buddy(&e4b);
> @@ -4354,6 +4357,7 @@ ext4_mb_discard_lg_preallocations(struct super_block *sb,
> err = ext4_mb_load_buddy_gfp(sb, group, &e4b,
> GFP_NOFS|__GFP_NOFAIL);
> if (err) {
> + ext4_set_errno(sb, -err);
> ext4_error(sb, "Error %d loading buddy information for %u",
> err, group);
> continue;
> diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
> index 9d00e0dd2ba9..87f7551c5132 100644
> --- a/fs/ext4/mmp.c
> +++ b/fs/ext4/mmp.c
> @@ -174,8 +174,10 @@ static int kmmpd(void *data)
> * (s_mmp_update_interval * 60) seconds.
> */
> if (retval) {
> - if ((failed_writes % 60) == 0)
> + if ((failed_writes % 60) == 0) {
> + ext4_set_errno(sb, -retval);
> ext4_error(sb, "Error writing to MMP block");
> + }
> failed_writes++;
> }
>
> @@ -206,6 +208,7 @@ static int kmmpd(void *data)
>
> retval = read_mmp_block(sb, &bh_check, mmp_block);
> if (retval) {
> + ext4_set_errno(sb, -retval);
> ext4_error(sb, "error reading MMP data: %d",
> retval);
> goto exit_thread;
> @@ -219,6 +222,7 @@ static int kmmpd(void *data)
> "Error while updating MMP info. "
> "The filesystem seems to have been"
> " multiply mounted.");
> + ext4_set_errno(sb, EBUSY);
> ext4_error(sb, "abort");
> put_bh(bh_check);
> retval = -EBUSY;
> diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
> index 9905720df924..5ec855a3b3e7 100644
> --- a/fs/ext4/namei.c
> +++ b/fs/ext4/namei.c
> @@ -156,6 +156,7 @@ static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
> if (ext4_dx_csum_verify(inode, dirent))
> set_buffer_verified(bh);
> else {
> + ext4_set_errno(inode->i_sb, EFSBADCRC);
> ext4_error_inode(inode, func, line, block,
> "Directory index failed checksum");
> brelse(bh);
> @@ -166,6 +167,7 @@ static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
> if (ext4_dirblock_csum_verify(inode, bh))
> set_buffer_verified(bh);
> else {
> + ext4_set_errno(inode->i_sb, EFSBADCRC);
> ext4_error_inode(inode, func, line, block,
> "Directory block failed checksum");
> brelse(bh);
> @@ -1528,6 +1530,7 @@ static struct buffer_head *__ext4_find_entry(struct inode *dir,
> goto next;
> wait_on_buffer(bh);
> if (!buffer_uptodate(bh)) {
> + ext4_set_errno(sb, EIO);
> EXT4_ERROR_INODE(dir, "reading directory lblock %lu",
> (unsigned long) block);
> brelse(bh);
> @@ -1538,6 +1541,7 @@ static struct buffer_head *__ext4_find_entry(struct inode *dir,
> !is_dx_internal_node(dir, block,
> (struct ext4_dir_entry *)bh->b_data) &&
> !ext4_dirblock_csum_verify(dir, bh)) {
> + ext4_set_errno(sb, EFSBADCRC);
> EXT4_ERROR_INODE(dir, "checksumming directory "
> "block %lu", (unsigned long)block);
> brelse(bh);
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index a29ec0fa3d71..41a384a744d3 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -367,6 +367,8 @@ static void __save_error_info(struct super_block *sb, const char *func,
> ext4_update_tstamp(es, s_last_error_time);
> strncpy(es->s_last_error_func, func, sizeof(es->s_last_error_func));
> es->s_last_error_line = cpu_to_le32(line);
> + if (es->s_last_error_errcode == 0)
> + es->s_last_error_errcode = EXT4_ERR_EFSCORRUPTED;
> if (!es->s_first_error_time) {
> es->s_first_error_time = es->s_last_error_time;
> es->s_first_error_time_hi = es->s_last_error_time_hi;
> @@ -375,6 +377,7 @@ static void __save_error_info(struct super_block *sb, const char *func,
> es->s_first_error_line = cpu_to_le32(line);
> es->s_first_error_ino = es->s_last_error_ino;
> es->s_first_error_block = es->s_last_error_block;
> + es->s_first_error_errcode = es->s_last_error_errcode;
> }
> /*
> * Start the daily error reporting function if it hasn't been
> @@ -713,6 +716,66 @@ const char *ext4_decode_error(struct super_block *sb, int errno,
> return errstr;
> }
>
> +void ext4_set_errno(struct super_block *sb, int err)
> +{
> + if (err < 0)
> + err = -err;
> +
> + switch (err) {
> + case EIO:
> + err = EXT4_ERR_EIO;
> + break;
> + case ENOMEM:
> + err = EXT4_ERR_ENOMEM;
> + break;
> + case EFSBADCRC:
> + err = EXT4_ERR_EFSBADCRC;
> + break;
> + case EFSCORRUPTED:
> + err = EXT4_ERR_EFSCORRUPTED;
> + break;
> + case ENOSPC:
> + err = EXT4_ERR_ENOSPC;
> + break;
> + case ENOKEY:
> + err = EXT4_ERR_ENOKEY;
> + break;
> + case EROFS:
> + err = EXT4_ERR_EROFS;
> + break;
> + case EFBIG:
> + err = EXT4_ERR_EFBIG;
> + break;
> + case EEXIST:
> + err = EXT4_ERR_EEXIST;
> + break;
> + case ERANGE:
> + err = EXT4_ERR_ERANGE;
> + break;
> + case EOVERFLOW:
> + err = EXT4_ERR_EOVERFLOW;
> + break;
> + case EBUSY:
> + err = EXT4_ERR_EBUSY;
> + break;
> + case ENOTDIR:
> + err = EXT4_ERR_ENOTDIR;
> + break;
> + case ENOTEMPTY:
> + err = EXT4_ERR_ENOTEMPTY;
> + break;
> + case ESHUTDOWN:
> + err = EXT4_ERR_ESHUTDOWN;
> + break;
> + case EFAULT:
> + err = EXT4_ERR_EFAULT;
> + break;
> + default:
> + err = EXT4_ERR_UNKNOWN;
> + }
> + EXT4_SB(sb)->s_es->s_last_error_errcode = err;
> +}
> +
> /* __ext4_std_error decodes expected errors from journaling functions
> * automatically and invokes the appropriate error response. */
>
> @@ -737,6 +800,7 @@ void __ext4_std_error(struct super_block *sb, const char *function,
> sb->s_id, function, line, errstr);
> }
>
> + ext4_set_errno(sb, -errno);
> save_error_info(sb, function, line);
> ext4_handle_error(sb);
> }
> @@ -1066,8 +1130,10 @@ static void ext4_put_super(struct super_block *sb)
> aborted = is_journal_aborted(sbi->s_journal);
> err = jbd2_journal_destroy(sbi->s_journal);
> sbi->s_journal = NULL;
> - if ((err < 0) && !aborted)
> + if ((err < 0) && !aborted) {
> + ext4_set_errno(sb, -err);
> ext4_abort(sb, "Couldn't clean up the journal");
> + }
> }
>
> ext4_unregister_sysfs(sb);
> diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
> index 20e40cac819e..aa3ec833b01f 100644
> --- a/fs/ext4/xattr.c
> +++ b/fs/ext4/xattr.c
> @@ -2908,9 +2908,11 @@ int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
> bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
> if (IS_ERR(bh)) {
> error = PTR_ERR(bh);
> - if (error == -EIO)
> + if (error == -EIO) {
> + ext4_set_errno(inode->i_sb, EIO);
> EXT4_ERROR_INODE(inode, "block %llu read error",
> EXT4_I(inode)->i_file_acl);
> + }
> bh = NULL;
> goto cleanup;
> }
>
--
-----------
Tim Gardner
Canonical, Inc
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