[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20241025100205.635960-1-lizhi.xu@windriver.com>
Date: Fri, 25 Oct 2024 18:02:05 +0800
From: Lizhi Xu <lizhi.xu@...driver.com>
To: <syzbot+9fc4dac4775d07bcfe34@...kaller.appspotmail.com>
CC: <bfoster@...hat.com>, <kent.overstreet@...ux.dev>,
<linux-bcachefs@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<syzkaller-bugs@...glegroups.com>
Subject: Re: [syzbot] [bcachefs?] KASAN: slab-use-after-free Read in bch2_reconstruct_alloc
The counters will cause sb to be realloc and release the old sb, which leads to uaf in ext
#syz test: upstream master
diff --git a/fs/bcachefs/recovery.c b/fs/bcachefs/recovery.c
index 55e1504a8130..9df0969c29ce 100644
--- a/fs/bcachefs/recovery.c
+++ b/fs/bcachefs/recovery.c
@@ -59,6 +59,7 @@ static void bch2_reconstruct_alloc(struct bch_fs *c)
mutex_lock(&c->sb_lock);
struct bch_sb_field_ext *ext = bch2_sb_field_get(c->disk_sb.sb, ext);
+ void *sb;
__set_bit_le64(BCH_RECOVERY_PASS_STABLE_check_allocations, ext->recovery_passes_required);
__set_bit_le64(BCH_RECOVERY_PASS_STABLE_check_alloc_info, ext->recovery_passes_required);
@@ -94,7 +95,10 @@ static void bch2_reconstruct_alloc(struct bch_fs *c)
__set_bit_le64(BCH_FSCK_ERR_accounting_mismatch, ext->errors_silent);
c->sb.compat &= ~(1ULL << BCH_COMPAT_alloc_info);
+ sb = c->disk_sb.sb;
bch2_write_super(c);
+ if (sb != c->disk_sb.sb)
+ ext = bch2_sb_field_get(c->disk_sb.sb, ext);
mutex_unlock(&c->sb_lock);
c->opts.recovery_passes |= bch2_recovery_passes_from_stable(le64_to_cpu(ext->recovery_passes_required[0]));
Powered by blists - more mailing lists