inode: move 'i_extra_size' to 'i_extra' buffer

[wimlib] / src / tagged_items.c

diff --git a/src/tagged_items.c b/src/tagged_items.c
index e3ba53f496612c7d95e8dabaa12d3512865edca6..723773f94be3e678afe6c0f88bae6a3355a961ce 100644 (file)
--- a/src/tagged_items.c
+++ b/src/tagged_items.c
@@ -44,12 +44,7 @@ struct tagged_item_header {
        le32 tag;
 
        /* Size of the data of this tagged item, in bytes.  This excludes this
-        * header and should be a multiple of 8.
-        *
-        * (Actually, the MS implementation seems to round this up to an 8 byte
-        * boundary when calculating the offset to the next tagged item, but
-        * uses this length unmodified when validating the item.  We might as
-        * well do the same.)  */
+        * header and should be a multiple of 8.  */
        le32 length;
 
        /* Variable length data  */
@@ -79,8 +74,14 @@ inode_get_tagged_item(const struct wim_inode *inode,
                      u32 desired_tag, u32 min_data_len)
 {
        size_t minlen_with_hdr = sizeof(struct tagged_item_header) + min_data_len;
-       size_t len_remaining = inode->i_extra_size;
-       u8 *p = inode->i_extra;
+       size_t len_remaining;
+       u8 *p;
+
+       if (!inode->i_extra)
+               return NULL;
+
+       len_remaining = inode->i_extra->size;
+       p = inode->i_extra->data;
 
        /* Iterate through the tagged items.  */
        while (len_remaining >= minlen_with_hdr) {
@@ -90,14 +91,16 @@ inode_get_tagged_item(const struct wim_inode *inode,
 
                hdr = (struct tagged_item_header *)p;
                tag = le32_to_cpu(hdr->tag);
-               len = le32_to_cpu(hdr->length);
+               len = ALIGN(le32_to_cpu(hdr->length), 8);
 
+               /* Length overflow?  */
+               if (unlikely(len > len_remaining - sizeof(struct tagged_item_header)))
+                       return NULL;
+
+               /* Matches the item we wanted?  */
                if (tag == desired_tag && len >= min_data_len)
                        return hdr->data;
 
-               len = (len + 7) & ~7;
-               if (len_remaining <= sizeof(struct tagged_item_header) + len)
-                       return NULL;
                len_remaining -= sizeof(struct tagged_item_header) + len;
                p += sizeof(struct tagged_item_header) + len;
        }
@@ -111,29 +114,31 @@ inode_add_tagged_item(struct wim_inode *inode, u32 tag, u32 len)
 {
        size_t itemsize;
        size_t newsize;
-       u8 *buf;
+       struct wim_inode_extra *extra;
        struct tagged_item_header *hdr;
 
        /* We prepend the item instead of appending it because it's easier.  */
 
-       itemsize = sizeof(struct tagged_item_header) + ((len + 7) & ~7);
-       newsize = itemsize + inode->i_extra_size;
+       itemsize = sizeof(struct tagged_item_header) + ALIGN(len, 8);
+       newsize = itemsize;
+       if (inode->i_extra)
+               newsize += inode->i_extra->size;
 
-       buf = MALLOC(newsize);
-       if (!buf)
+       extra = MALLOC(sizeof(struct wim_inode_extra) + newsize);
+       if (!extra)
                return NULL;
-
-       if (inode->i_extra_size) {
-               memcpy(buf + itemsize, inode->i_extra, inode->i_extra_size);
+       if (inode->i_extra) {
+               memcpy(&extra->data[itemsize], inode->i_extra->data,
+                      inode->i_extra->size);
                FREE(inode->i_extra);
        }
-       inode->i_extra = buf;
-       inode->i_extra_size = newsize;
+       extra->size = newsize;
+       inode->i_extra = extra;
 
-       hdr = (struct tagged_item_header *)buf;
+       hdr = (struct tagged_item_header *)extra->data;
        hdr->tag = cpu_to_le32(tag);
        hdr->length = cpu_to_le32(len);
-       return memset(hdr->data, 0, (len + 7) & ~7);
+       return memset(hdr->data, 0, ALIGN(len, 8));
 }
 
 static inline struct wimlib_unix_data_disk *