From 2fe79ce7d1e8ec5059e7dfc15f3c769ae9679569 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Thu, 20 Jun 2024 19:42:39 -0400 Subject: [PATCH] bcachefs: Fix a UAF after write_super() write_super() may reallocate the superblock buffer - but bch_sb_field_ext was referencing it; don't use it after the write_super call. Reported-by: syzbot+8992fc10a192067b8d8a@syzkaller.appspotmail.com Signed-off-by: Kent Overstreet --- fs/bcachefs/recovery.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/bcachefs/recovery.c b/fs/bcachefs/recovery.c index e632da69196cc..1f9d044ed9207 100644 --- a/fs/bcachefs/recovery.c +++ b/fs/bcachefs/recovery.c @@ -664,10 +664,10 @@ int bch2_fs_recovery(struct bch_fs *c) if (check_version_upgrade(c)) write_sb = true; + c->recovery_passes_explicit |= bch2_recovery_passes_from_stable(le64_to_cpu(ext->recovery_passes_required[0])); + if (write_sb) bch2_write_super(c); - - c->recovery_passes_explicit |= bch2_recovery_passes_from_stable(le64_to_cpu(ext->recovery_passes_required[0])); mutex_unlock(&c->sb_lock); if (c->opts.fsck && IS_ENABLED(CONFIG_BCACHEFS_DEBUG)) -- 2.49.0