Commit 164dfada 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-v4.19.322
commit b90beafac05931cbfcb6b1bd4f67c1923f47040e
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=b90beafac05931cbfcb6b1bd4f67c1923f47040e

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

[ Upstream commit 683408258917541bdb294cd717c210a04381931e ]

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 avatarSasha Levin <sashal@kernel.org>

Conflicts:
	fs/nilfs2/sysfs.c
[3bcd6c5b not merged.]
Signed-off-by: default avatarZhao Wenhui <zhaowenhui8@huawei.com>
parent c1c5cd9a

fs/nilfs2/sysfs.c

+33 −10
Original line number Diff line number Diff line
@@ -845,9 +845,15 @@ 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 snprintf(buf, PAGE_SIZE, "%d.%d\n", major, minor);

}
@@ -865,8 +871,13 @@ 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 snprintf(buf, PAGE_SIZE, "%llu\n", dev_size);

}
@@ -888,9 +899,15 @@ 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 snprintf(buf, PAGE_SIZE, "%pUb\n", sbp[0]->s_uuid);

	down_read(&nilfs->ns_sem);

	raw_sb = nilfs->ns_sbp[0];

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

	up_read(&nilfs->ns_sem);



	return len;

}



static
@@ -898,10 +915,16 @@ 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[] =