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 A1033171A1 for ; Mon, 22 May 2023 19:25:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1FF25C433D2; Mon, 22 May 2023 19:25:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1684783538; bh=uSuoodPlvrw0FhXkwxiXvWD5EvuhdjzFAJdzq1s+Wto=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UgeZc7ORToG0S5Oq3LVXeZ1In/Hkis28BL1wx8ImJU2eHwHC6MjhoxE8bqWsqpSKt 8wuNI/usbnE7w/Q/S4kRzyjUNV2e14Gg6fAa6Fru15ZM2DcyTTWKYnLMS8d/Nhkaig pQRKRtejT8nK/hbwgFweC4vE9SbYvB8UA3w6E0U8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+4fec412f59eba8c01b77@syzkaller.appspotmail.com, Jan Kara , Sasha Levin Subject: [PATCH 6.1 077/292] ext2: Check block size validity during mount Date: Mon, 22 May 2023 20:07:14 +0100 Message-Id: <20230522190407.895444828@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230522190405.880733338@linuxfoundation.org> References: <20230522190405.880733338@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: Jan Kara [ Upstream commit 62aeb94433fcec80241754b70d0d1836d5926b0a ] Check that log of block size stored in the superblock has sensible value. Otherwise the shift computing the block size can overflow leading to undefined behavior. Reported-by: syzbot+4fec412f59eba8c01b77@syzkaller.appspotmail.com Signed-off-by: Jan Kara Signed-off-by: Sasha Levin --- fs/ext2/ext2.h | 1 + fs/ext2/super.c | 7 +++++++ 2 files changed, 8 insertions(+) diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h index 28de11a22e5f6..dc5dcb78bc27f 100644 --- a/fs/ext2/ext2.h +++ b/fs/ext2/ext2.h @@ -180,6 +180,7 @@ static inline struct ext2_sb_info *EXT2_SB(struct super_block *sb) #define EXT2_MIN_BLOCK_SIZE 1024 #define EXT2_MAX_BLOCK_SIZE 4096 #define EXT2_MIN_BLOCK_LOG_SIZE 10 +#define EXT2_MAX_BLOCK_LOG_SIZE 16 #define EXT2_BLOCK_SIZE(s) ((s)->s_blocksize) #define EXT2_ADDR_PER_BLOCK(s) (EXT2_BLOCK_SIZE(s) / sizeof (__u32)) #define EXT2_BLOCK_SIZE_BITS(s) ((s)->s_blocksize_bits) diff --git a/fs/ext2/super.c b/fs/ext2/super.c index 03f2af98b1b48..3feea4b31fa7e 100644 --- a/fs/ext2/super.c +++ b/fs/ext2/super.c @@ -945,6 +945,13 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent) goto failed_mount; } + if (le32_to_cpu(es->s_log_block_size) > + (EXT2_MAX_BLOCK_LOG_SIZE - BLOCK_SIZE_BITS)) { + ext2_msg(sb, KERN_ERR, + "Invalid log block size: %u", + le32_to_cpu(es->s_log_block_size)); + goto failed_mount; + } blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size); if (test_opt(sb, DAX)) { -- 2.39.2