There is a use-after-free possibility in __ext4_journal_stop() in the
case that we free the handle in the first jbd2_journal_stop() because
we're referencing handle->h_err afterwards. This was introduced in
9705acd63b125dee8b15c705216d7186daea4625 and it is wrong. Fix it by
storing the handle->h_err value beforehand and avoid referencing
potentially freed handle.
Signed-off-by: Lukas Czerner <lczerner@xxxxxxxxxx>
---
fs/ext4/ext4_jbd2.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c
index d418431..e770c1ee 100644
--- a/fs/ext4/ext4_jbd2.c
+++ b/fs/ext4/ext4_jbd2.c
@@ -88,13 +88,13 @@ int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle)
return 0;
}
+ err = handle->h_err;
if (!handle->h_transaction) {
- err = jbd2_journal_stop(handle);
- return handle->h_err ? handle->h_err : err;
+ rc = jbd2_journal_stop(handle);
+ return err ? err : rc;
}
sb = handle->h_transaction->t_journal->j_private;
- err = handle->h_err;
rc = jbd2_journal_stop(handle);
if (!err)
--
1.8.3.1
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