diff options
| author | Pratik Shinde <pratikshinde320@gmail.com> | 2019-11-04 10:49:37 +0800 |
|---|---|---|
| committer | Gao Xiang <gaoxiang25@huawei.com> | 2019-11-24 11:02:41 +0800 |
| commit | b858a4844cfba3d90a8d8ffd3a04d9557f76b60f (patch) | |
| tree | e6f4c00ffe6fdd09fd393910f444c7bad2682d36 /fs/erofs/super.c | |
| parent | a93f8c36877b2ae9ba0ca07eda1933944dc5bcb8 (diff) | |
erofs: support superblock checksum
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>
Diffstat (limited to 'fs/erofs/super.c')
| -rw-r--r-- | fs/erofs/super.c | 36 |
1 files changed, 34 insertions, 2 deletions
diff --git a/fs/erofs/super.c b/fs/erofs/super.c index 0e369494f2f2..849c0bdf49d9 100644 --- a/fs/erofs/super.c +++ b/fs/erofs/super.c @@ -9,6 +9,7 @@ #include <linux/statfs.h> #include <linux/parser.h> #include <linux/seq_file.h> +#include <linux/crc32c.h> #include "xattr.h" #define CREATE_TRACE_POINTS @@ -46,6 +47,30 @@ void _erofs_info(struct super_block *sb, const char *function, 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) { struct erofs_inode *vi = ptr; @@ -112,7 +137,7 @@ static int erofs_read_superblock(struct super_block *sb) sbi = EROFS_SB(sb); - data = kmap_atomic(page); + data = kmap(page); dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET); ret = -EINVAL; @@ -121,6 +146,13 @@ static int erofs_read_superblock(struct super_block *sb) 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; /* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */ if (blkszbits != LOG_BLOCK_SIZE) { @@ -155,7 +187,7 @@ static int erofs_read_superblock(struct super_block *sb) } ret = 0; out: - kunmap_atomic(data); + kunmap(page); put_page(page); return ret; } |