From: Lukas Czerner Date: Sun, 18 Oct 2015 02:57:06 +0000 (-0400) Subject: ext4: fix potential use after free in __ext4_journal_stop X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=6934da9238da947628be83635e365df41064b09b;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git ext4: fix potential use after free in __ext4_journal_stop 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. Fixes: 9705acd63b125dee8b15c705216d7186daea4625 Signed-off-by: Lukas Czerner Reviewed-by: Andreas Dilger Cc: stable@vger.kernel.org --- diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c index d41843181818..e770c1ee4613 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)