From: Ye Bin Date: Wed, 14 Sep 2022 10:08:12 +0000 (+0800) Subject: jbd2: fix potential use-after-free in jbd2_fc_wait_bufs X-Git-Tag: v5.19.17~597 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2e6d9f381c1ed844531a577783fc352de7a44c8a;p=thirdparty%2Fkernel%2Fstable.git jbd2: fix potential use-after-free in jbd2_fc_wait_bufs commit 243d1a5d505d0b0460c9af0ad56ed4a56ef0bebd upstream. In 'jbd2_fc_wait_bufs' use 'bh' after put buffer head reference count which may lead to use-after-free. So judge buffer if uptodate before put buffer head reference count. Cc: stable@kernel.org Signed-off-by: Ye Bin Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20220914100812.1414768-3-yebin10@huawei.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index c67b315d379a8..e4c1994f01ad6 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -926,16 +926,16 @@ int jbd2_fc_wait_bufs(journal_t *journal, int num_blks) for (i = j_fc_off - 1; i >= j_fc_off - num_blks; i--) { bh = journal->j_fc_wbuf[i]; wait_on_buffer(bh); - put_bh(bh); - journal->j_fc_wbuf[i] = NULL; /* * Update j_fc_off so jbd2_fc_release_bufs can release remain * buffer head. */ if (unlikely(!buffer_uptodate(bh))) { - journal->j_fc_off = i; + journal->j_fc_off = i + 1; return -EIO; } + put_bh(bh); + journal->j_fc_wbuf[i] = NULL; } return 0;