gentoo-overlay/sys-kernel/hardened-kernel/files/linux-6.12/0134-bcachefs-Guard-against...

64 lines
2.1 KiB
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From a5d7cf346646cb3d58221d896ed65224a306bf8f Mon Sep 17 00:00:00 2001
From: Kent Overstreet <kent.overstreet@linux.dev>
Date: Wed, 27 Nov 2024 21:58:43 -0500
Subject: [PATCH 134/233] bcachefs: Guard against journal seq overflow
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 8bit
Wraparound is impractical to handle since in various places we use 0 as
a sentinal value - but 64 bits (or 56, because the btree write buffer
steals a few bits) is enough for all practical purposes.
Reported-by: syzbot+73ed43fbe826227bd4e0@syzkaller.appspotmail.com
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Alexander Miroshnichenko <alex@millerson.name>
---
fs/bcachefs/journal.c | 9 +++++++++
fs/bcachefs/journal_types.h | 3 +++
2 files changed, 12 insertions(+)
diff --git a/fs/bcachefs/journal.c b/fs/bcachefs/journal.c
index 95cccda3b22c..dc66521964b7 100644
--- a/fs/bcachefs/journal.c
+++ b/fs/bcachefs/journal.c
@@ -382,6 +382,10 @@ static int journal_entry_open(struct journal *j)
if (nr_unwritten_journal_entries(j) == ARRAY_SIZE(j->buf))
return JOURNAL_ERR_max_in_flight;
+ if (bch2_fs_fatal_err_on(journal_cur_seq(j) >= JOURNAL_SEQ_MAX,
+ c, "cannot start: journal seq overflow"))
+ return JOURNAL_ERR_insufficient_devices; /* -EROFS */
+
BUG_ON(!j->cur_entry_sectors);
buf->expires =
@@ -1270,6 +1274,11 @@ int bch2_fs_journal_start(struct journal *j, u64 cur_seq)
bool had_entries = false;
u64 last_seq = cur_seq, nr, seq;
+ if (cur_seq >= JOURNAL_SEQ_MAX) {
+ bch_err(c, "cannot start: journal seq overflow");
+ return -EINVAL;
+ }
+
genradix_for_each_reverse(&c->journal_entries, iter, _i) {
i = *_i;
diff --git a/fs/bcachefs/journal_types.h b/fs/bcachefs/journal_types.h
index 425d1abb257e..e9bd716fbb71 100644
--- a/fs/bcachefs/journal_types.h
+++ b/fs/bcachefs/journal_types.h
@@ -9,6 +9,9 @@
#include "super_types.h"
#include "fifo.h"
+/* btree write buffer steals 8 bits for its own purposes: */
+#define JOURNAL_SEQ_MAX ((1ULL << 56) - 1)
+
#define JOURNAL_BUF_BITS 2
#define JOURNAL_BUF_NR (1U << JOURNAL_BUF_BITS)
#define JOURNAL_BUF_MASK (JOURNAL_BUF_NR - 1)
--
2.45.2