@@ -67,6 +67,39 @@ static int adfs_fplus_validate_tail(const struct adfs_bigdirheader *h,
return 0;
}
+static u8 adfs_fplus_checkbyte(struct adfs_dir *dir)
+{
+ struct adfs_bigdirheader *h = dir->bighead;
+ struct adfs_bigdirtail *t = dir->bigtail;
+ unsigned int end, bs, bi, i;
+ __le32 *bp;
+ u32 dircheck;
+
+ end = adfs_fplus_offset(h, le32_to_cpu(h->bigdirentries)) +
+ le32_to_cpu(h->bigdirnamesize);
+
+ /* Accumulate the contents of the header, entries and names */
+ for (dircheck = 0, bi = 0; end; bi++) {
+ bp = (void *)dir->bhs[bi]->b_data;
+ bs = dir->bhs[bi]->b_size;
+ if (bs > end)
+ bs = end;
+
+ for (i = 0; i < bs; i += sizeof(u32))
+ dircheck = ror32(dircheck, 13) ^ le32_to_cpup(bp++);
+
+ end -= bs;
+ }
+
+ /* Accumulate the contents of the tail except for the check byte */
+ dircheck = ror32(dircheck, 13) ^ le32_to_cpu(t->bigdirendname);
+ dircheck = ror32(dircheck, 13) ^ t->bigdirendmasseq;
+ dircheck = ror32(dircheck, 13) ^ t->reserved[0];
+ dircheck = ror32(dircheck, 13) ^ t->reserved[1];
+
+ return dircheck ^ dircheck >> 8 ^ dircheck >> 16 ^ dircheck >> 24;
+}
+
static int adfs_fplus_read(struct super_block *sb, u32 indaddr,
unsigned int size, struct adfs_dir *dir)
{
@@ -107,6 +140,11 @@ static int adfs_fplus_read(struct super_block *sb, u32 indaddr,
goto out;
}
+ if (adfs_fplus_checkbyte(dir) != t->bigdircheckbyte) {
+ adfs_error(sb, "dir %06x checkbyte mismatch\n", indaddr);
+ goto out;
+ }
+
dir->parent_id = le32_to_cpu(h->bigdirparent);
return 0;
When reading a big directory, calculate the validate the directory checkbyte to ensure that the directory contents are valid. Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> --- fs/adfs/dir_fplus.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+)