Commit 48c4d3be authored by Ryusuke Konishi's avatar Ryusuke Konishi Committed by Zhao Wenhui
Browse files

nilfs2: protect references to superblock parameters exposed in sysfs 

stable inclusion
from stable-v6.6.51
commit 8c6e43b3d5f109cf9c61bc188fcc8175404e924f
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IARYCR
CVE: CVE-2024-46780

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8c6e43b3d5f109cf9c61bc188fcc8175404e924f

--------------------------------

commit 683408258917541bdb294cd717c210a04381931e upstream.

The superblock buffers of nilfs2 can not only be overwritten at runtime
for modifications/repairs, but they are also regularly swapped, replaced
during resizing, and even abandoned when degrading to one side due to
backing device issues.  So, accessing them requires mutual exclusion using
the reader/writer semaphore "nilfs->ns_sem".

Some sysfs attribute show methods read this superblock buffer without the
necessary mutual exclusion, which can cause problems with pointer
dereferencing and memory access, so fix it.

Link: https://lkml.kernel.org/r/20240811100320.9913-1-konishi.ryusuke@gmail.com


Fixes: da7141fb ("nilfs2: add /sys/fs/nilfs2/<device> group")
Signed-off-by: default avatarRyusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarZhao Wenhui <zhaowenhui8@huawei.com>
parent bde3235c

fs/nilfs2/sysfs.c

+33 −10
Original line number Diff line number Diff line
@@ -836,9 +836,15 @@ ssize_t nilfs_dev_revision_show(struct nilfs_dev_attr *attr, 
				struct the_nilfs *nilfs,

				char *buf)

{

	struct nilfs_super_block **sbp = nilfs->ns_sbp;

	u32 major = le32_to_cpu(sbp[0]->s_rev_level);

	u16 minor = le16_to_cpu(sbp[0]->s_minor_rev_level);

	struct nilfs_super_block *raw_sb;

	u32 major;

	u16 minor;



	down_read(&nilfs->ns_sem);

	raw_sb = nilfs->ns_sbp[0];

	major = le32_to_cpu(raw_sb->s_rev_level);

	minor = le16_to_cpu(raw_sb->s_minor_rev_level);

	up_read(&nilfs->ns_sem);



	return sysfs_emit(buf, "%d.%d\n", major, minor);

}
@@ -856,8 +862,13 @@ ssize_t nilfs_dev_device_size_show(struct nilfs_dev_attr *attr, 
				    struct the_nilfs *nilfs,

				    char *buf)

{

	struct nilfs_super_block **sbp = nilfs->ns_sbp;

	u64 dev_size = le64_to_cpu(sbp[0]->s_dev_size);

	struct nilfs_super_block *raw_sb;

	u64 dev_size;



	down_read(&nilfs->ns_sem);

	raw_sb = nilfs->ns_sbp[0];

	dev_size = le64_to_cpu(raw_sb->s_dev_size);

	up_read(&nilfs->ns_sem);



	return sysfs_emit(buf, "%llu\n", dev_size);

}
@@ -879,9 +890,15 @@ ssize_t nilfs_dev_uuid_show(struct nilfs_dev_attr *attr, 
			    struct the_nilfs *nilfs,

			    char *buf)

{

	struct nilfs_super_block **sbp = nilfs->ns_sbp;

	struct nilfs_super_block *raw_sb;

	ssize_t len;



	return sysfs_emit(buf, "%pUb\n", sbp[0]->s_uuid);

	down_read(&nilfs->ns_sem);

	raw_sb = nilfs->ns_sbp[0];

	len = sysfs_emit(buf, "%pUb\n", raw_sb->s_uuid);

	up_read(&nilfs->ns_sem);



	return len;

}



static
@@ -889,10 +906,16 @@ ssize_t nilfs_dev_volume_name_show(struct nilfs_dev_attr *attr, 
				    struct the_nilfs *nilfs,

				    char *buf)

{

	struct nilfs_super_block **sbp = nilfs->ns_sbp;

	struct nilfs_super_block *raw_sb;

	ssize_t len;



	down_read(&nilfs->ns_sem);

	raw_sb = nilfs->ns_sbp[0];

	len = scnprintf(buf, sizeof(raw_sb->s_volume_name), "%s\n",

			raw_sb->s_volume_name);

	up_read(&nilfs->ns_sem);



	return scnprintf(buf, sizeof(sbp[0]->s_volume_name), "%s\n",

			 sbp[0]->s_volume_name);

	return len;

}



static const char dev_readme_str[] =