From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E8BF11C08 for ; Wed, 28 Dec 2022 16:46:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 678D4C433D2; Wed, 28 Dec 2022 16:46:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1672245987; bh=7/UN4rxCVt3+fYonT/vt3KbqXzFbTHIWNP6ebRLf9q4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fC+PYVxF8SPMhenkFyq2wAcYOmAfCycBLpQPbfH8+TRPX75fZ4AjpfCW4gCf34Eqr hCcJTOnTxRkPeubbRZAjo4yaI7wYksQMxAAhuYx3/lqjsBtTA2OoGxxpg4pDXay5KS uZCmZJcJOqU6+9uHcteKhBS0Pi9f62deR9J0f8ig= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ryusuke Konishi , Andrew Morton , Sasha Levin Subject: [PATCH 6.1 0958/1146] nilfs2: fix shift-out-of-bounds due to too large exponent of block size Date: Wed, 28 Dec 2022 15:41:37 +0100 Message-Id: <20221228144356.341466390@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20221228144330.180012208@linuxfoundation.org> References: <20221228144330.180012208@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Ryusuke Konishi [ Upstream commit ebeccaaef67a4895d2496ab8d9c2fb8d89201211 ] If field s_log_block_size of superblock data is corrupted and too large, init_nilfs() and load_nilfs() still can trigger a shift-out-of-bounds warning followed by a kernel panic (if panic_on_warn is set): shift exponent 38973 is too large for 32-bit type 'int' Call Trace: dump_stack_lvl+0xcd/0x134 ubsan_epilogue+0xb/0x50 __ubsan_handle_shift_out_of_bounds.cold.12+0x17b/0x1f5 init_nilfs.cold.11+0x18/0x1d [nilfs2] nilfs_mount+0x9b5/0x12b0 [nilfs2] ... This fixes the issue by adding and using a new helper function for getting block size with sanity check. Link: https://lkml.kernel.org/r/20221027044306.42774-3-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi Tested-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin --- fs/nilfs2/the_nilfs.c | 42 ++++++++++++++++++++++++++++++++++++++---- 1 file changed, 38 insertions(+), 4 deletions(-) diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c index a7c829a7d4f1..2064e6473d30 100644 --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -193,6 +193,34 @@ static int nilfs_store_log_cursor(struct the_nilfs *nilfs, return ret; } +/** + * nilfs_get_blocksize - get block size from raw superblock data + * @sb: super block instance + * @sbp: superblock raw data buffer + * @blocksize: place to store block size + * + * nilfs_get_blocksize() calculates the block size from the block size + * exponent information written in @sbp and stores it in @blocksize, + * or aborts with an error message if it's too large. + * + * Return Value: On success, 0 is returned. If the block size is too + * large, -EINVAL is returned. + */ +static int nilfs_get_blocksize(struct super_block *sb, + struct nilfs_super_block *sbp, int *blocksize) +{ + unsigned int shift_bits = le32_to_cpu(sbp->s_log_block_size); + + if (unlikely(shift_bits > + ilog2(NILFS_MAX_BLOCK_SIZE) - BLOCK_SIZE_BITS)) { + nilfs_err(sb, "too large filesystem blocksize: 2 ^ %u KiB", + shift_bits); + return -EINVAL; + } + *blocksize = BLOCK_SIZE << shift_bits; + return 0; +} + /** * load_nilfs - load and recover the nilfs * @nilfs: the_nilfs structure to be released @@ -246,11 +274,15 @@ int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb) nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime); /* verify consistency between two super blocks */ - blocksize = BLOCK_SIZE << le32_to_cpu(sbp[0]->s_log_block_size); + err = nilfs_get_blocksize(sb, sbp[0], &blocksize); + if (err) + goto scan_error; + if (blocksize != nilfs->ns_blocksize) { nilfs_warn(sb, "blocksize differs between two super blocks (%d != %d)", blocksize, nilfs->ns_blocksize); + err = -EINVAL; goto scan_error; } @@ -609,9 +641,11 @@ int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data) if (err) goto failed_sbh; - blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size); - if (blocksize < NILFS_MIN_BLOCK_SIZE || - blocksize > NILFS_MAX_BLOCK_SIZE) { + err = nilfs_get_blocksize(sb, sbp, &blocksize); + if (err) + goto failed_sbh; + + if (blocksize < NILFS_MIN_BLOCK_SIZE) { nilfs_err(sb, "couldn't mount because of unsupported filesystem blocksize %d", blocksize); -- 2.35.1