korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-24 20:54:10 +08:00
Code Issues Packages Projects Releases Wiki Activity

erofs: support superblock checksum

Browse Source 
Introduce superblock checksum feature in order to
check at mounting time.

Note that the first 1024 bytes are ignore for x86
boot sectors and other oddities.

Link: https://lore.kernel.org/r/20191104024937.113939-1-gaoxiang25@huawei.com
Signed-off-by: Pratik Shinde <pratikshinde320@gmail.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
This commit is contained in:
Pratik Shinde 2019-11-04 10:49:37 +08:00 committed by Gao Xiang
parent a93f8c3687
commit b858a4844c
4 changed files with 38 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
fs/erofs/Kconfig
View File

@ -3,6 +3,7 @@
config EROFS_FS config EROFS_FS
tristate "EROFS filesystem support" tristate "EROFS filesystem support"
depends on BLOCK depends on BLOCK
select LIBCRC32C
help help
EROFS (Enhanced Read-Only File System) is a lightweight EROFS (Enhanced Read-Only File System) is a lightweight
read-only file system with modern designs (eg. page-sized read-only file system with modern designs (eg. page-sized

3
fs/erofs/erofs_fs.h
View File

@ -11,6 +11,8 @@
#define EROFS_SUPER_OFFSET 1024 #define EROFS_SUPER_OFFSET 1024
#define EROFS_FEATURE_COMPAT_SB_CHKSUM 0x00000001
/* /*
* Any bits that aren't in EROFS_ALL_FEATURE_INCOMPAT should * Any bits that aren't in EROFS_ALL_FEATURE_INCOMPAT should
* be incompatible with this kernel version. * be incompatible with this kernel version.
@ -37,7 +39,6 @@ struct erofs_super_block {
__u8 uuid[16]; /* 128-bit uuid for volume */ __u8 uuid[16]; /* 128-bit uuid for volume */
__u8 volume_name[16]; /* volume name */ __u8 volume_name[16]; /* volume name */
__le32 feature_incompat; __le32 feature_incompat;
__u8 reserved2[44]; __u8 reserved2[44];
}; };

1
fs/erofs/internal.h
View File

@ -85,6 +85,7 @@ struct erofs_sb_info {
u8 uuid[16]; /* 128-bit uuid for volume */ u8 uuid[16]; /* 128-bit uuid for volume */
u8 volume_name[16]; /* volume name */ u8 volume_name[16]; /* volume name */
u32 feature_compat;
u32 feature_incompat; u32 feature_incompat;
unsigned int mount_opt; unsigned int mount_opt;

36
fs/erofs/super.c
View File

@ -9,6 +9,7 @@
#include <linux/statfs.h> #include <linux/statfs.h>
#include <linux/parser.h> #include <linux/parser.h>
#include <linux/seq_file.h> #include <linux/seq_file.h>
#include <linux/crc32c.h>
#include "xattr.h" #include "xattr.h"
#define CREATE_TRACE_POINTS #define CREATE_TRACE_POINTS
@ -46,6 +47,30 @@ void _erofs_info(struct super_block *sb, const char *function,
va_end(args); va_end(args);
} }
static int erofs_superblock_csum_verify(struct super_block *sb, void *sbdata)
{
struct erofs_super_block *dsb;
u32 expected_crc, crc;
dsb = kmemdup(sbdata + EROFS_SUPER_OFFSET,
EROFS_BLKSIZ - EROFS_SUPER_OFFSET, GFP_KERNEL);
if (!dsb)
return -ENOMEM;
expected_crc = le32_to_cpu(dsb->checksum);
dsb->checksum = 0;
/* to allow for x86 boot sectors and other oddities. */
crc = crc32c(~0, dsb, EROFS_BLKSIZ - EROFS_SUPER_OFFSET);
kfree(dsb);
if (crc != expected_crc) {
erofs_err(sb, "invalid checksum 0x%08x, 0x%08x expected",
crc, expected_crc);
return -EBADMSG;
}
return 0;
}
static void erofs_inode_init_once(void *ptr) static void erofs_inode_init_once(void *ptr)
{ {
struct erofs_inode *vi = ptr; struct erofs_inode *vi = ptr;
@ -112,7 +137,7 @@ static int erofs_read_superblock(struct super_block *sb)
sbi = EROFS_SB(sb); sbi = EROFS_SB(sb);
data = kmap_atomic(page); data = kmap(page);
dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET); dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
ret = -EINVAL; ret = -EINVAL;
@ -121,6 +146,13 @@ static int erofs_read_superblock(struct super_block *sb)
goto out; goto out;
} }
sbi->feature_compat = le32_to_cpu(dsb->feature_compat);
if (sbi->feature_compat & EROFS_FEATURE_COMPAT_SB_CHKSUM) {
ret = erofs_superblock_csum_verify(sb, data);
if (ret)
goto out;
}
blkszbits = dsb->blkszbits; blkszbits = dsb->blkszbits;
/* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */ /* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */
if (blkszbits != LOG_BLOCK_SIZE) { if (blkszbits != LOG_BLOCK_SIZE) {
@ -155,7 +187,7 @@ static int erofs_read_superblock(struct super_block *sb)
} }
ret = 0; ret = 0;
out: out:
kunmap_atomic(data); kunmap(page);
put_page(page); put_page(page);
return ret; return ret;
} }