diff options
| author | Kent Overstreet <kent.overstreet@linux.dev> | 2024-05-25 12:38:53 -0400 |
|---|---|---|
| committer | Kent Overstreet <kent.overstreet@linux.dev> | 2024-06-29 16:55:51 -0400 |
| commit | 8e4dc66768a38acbadc3d84fb070d1220d0fbebd (patch) | |
| tree | 595581a24058e996dfb39e3dce729545896113fa | |
| parent | fc21785d6383b87a48601eab8c1df26a5572ca43 (diff) | |
bcachefs: Fix sb-downgrade validation
Superblock downgrade entries are only two byte aligned, but section
sizes are 8 byte aligned, which means we have to be careful about
overrun checks; an entry that crosses the end of the section is allowed
(and ignored) as long as it has zero errors.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
(cherry picked from commit 9242a34b760648b722f4958749ad83ef7d0f7525)
| -rw-r--r-- | fs/bcachefs/sb-downgrade.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/fs/bcachefs/sb-downgrade.c b/fs/bcachefs/sb-downgrade.c index 13fb3292aba4..b01d4969fe02 100644 --- a/fs/bcachefs/sb-downgrade.c +++ b/fs/bcachefs/sb-downgrade.c @@ -146,6 +146,14 @@ static int bch2_sb_downgrade_validate(struct bch_sb *sb, struct bch_sb_field *f, for (const struct bch_sb_field_downgrade_entry *i = e->entries; (void *) i < vstruct_end(&e->field); i = downgrade_entry_next_c(i)) { + /* + * Careful: sb_field_downgrade_entry is only 2 byte aligned, but + * section sizes are 8 byte aligned - an empty entry spanning + * the end of the section is allowed (and ignored): + */ + if ((void *) &i->errors[0] > vstruct_end(&e->field)) + break; + if (BCH_VERSION_MAJOR(le16_to_cpu(i->version)) != BCH_VERSION_MAJOR(le16_to_cpu(sb->version))) { prt_printf(err, "downgrade entry with mismatched major version (%u != %u)", |