#define EROFS_SUPER_OFFSET 1024
+#define EROFS_FEATURE_COMPAT_SB_CHKSUM 0x00000001
+
/*
* Any bits that aren't in EROFS_ALL_FEATURE_INCOMPAT should
* be incompatible with this kernel version.
__u8 uuid[16]; /* 128-bit uuid for volume */
__u8 volume_name[16]; /* volume name */
__le32 feature_incompat;
-
__u8 reserved2[44];
};
#include <linux/statfs.h>
#include <linux/parser.h>
#include <linux/seq_file.h>
+#include <linux/crc32c.h>
#include "xattr.h"
#define CREATE_TRACE_POINTS
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;
sbi = EROFS_SB(sb);
- data = kmap_atomic(page);
+ data = kmap(page);
dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
ret = -EINVAL;
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) {
}
ret = 0;
out:
- kunmap_atomic(data);
+ kunmap(page);
put_page(page);
return ret;
}