lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20230504194413.3806354-7-sashal@kernel.org>
Date:   Thu,  4 May 2023 15:43:27 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Jan Kara <jack@...e.cz>,
        syzbot+4fec412f59eba8c01b77@...kaller.appspotmail.com,
        Sasha Levin <sashal@...nel.org>, jack@...e.com,
        linux-ext4@...r.kernel.org
Subject: [PATCH AUTOSEL 6.2 07/53] ext2: Check block size validity during mount

From: Jan Kara <jack@...e.cz>

[ 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@...kaller.appspotmail.com
Signed-off-by: Jan Kara <jack@...e.cz>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 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 69c88facfe90e..f342f347a695f 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

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ