[PATCH/WIP 04/11] tree-walk.c: do not leak internal structure in tree_entry_len()

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

tree_entry_len() does not simply take two random arguments and return
a tree length. The two pointers must point to a tree item structure,
or struct name_entry. Passing random pointers will return incorrect
value.

Force callers to pass struct name_entry instead of two pointers (with
hope that they don't manually construct struct name_entry themselves)

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 builtin/grep.c         |    2 +-
 builtin/pack-objects.c |    2 +-
 tree-diff.c            |    6 +++---
 tree-walk.c            |   16 ++++++++--------
 tree-walk.h            |    6 +++---
 tree.c                 |    2 +-
 unpack-trees.c         |    6 +++---
 7 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/builtin/grep.c b/builtin/grep.c
index 7d0779f..2cd0612 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -547,7 +547,7 @@ static int grep_tree(struct grep_opt *opt, const struct pathspec *pathspec,
 	int old_baselen = base->len;
 
 	while (tree_entry(tree, &entry)) {
-		int te_len = tree_entry_len(entry.path, entry.sha1);
+		int te_len = tree_entry_len(&entry);
 
 		if (match != 2) {
 			match = tree_entry_interesting(&entry, base, tn_len, pathspec);
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 2b18de5..864154b 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -975,7 +975,7 @@ static void add_pbase_object(struct tree_desc *tree,
 	while (tree_entry(tree,&entry)) {
 		if (S_ISGITLINK(entry.mode))
 			continue;
-		cmp = tree_entry_len(entry.path, entry.sha1) != cmplen ? 1 :
+		cmp = tree_entry_len(&entry) != cmplen ? 1 :
 		      memcmp(name, entry.path, cmplen);
 		if (cmp > 0)
 			continue;
diff --git a/tree-diff.c b/tree-diff.c
index b3cc2e4..6782484 100644
--- a/tree-diff.c
+++ b/tree-diff.c
@@ -21,8 +21,8 @@ static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2,
 	sha1 = tree_entry_extract(t1, &path1, &mode1);
 	sha2 = tree_entry_extract(t2, &path2, &mode2);
 
-	pathlen1 = tree_entry_len(path1, sha1);
-	pathlen2 = tree_entry_len(path2, sha2);
+	pathlen1 = tree_entry_len(&t1->entry);
+	pathlen2 = tree_entry_len(&t2->entry);
 	cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
 	if (cmp < 0) {
 		show_entry(opt, "-", t1, base);
@@ -85,7 +85,7 @@ static void show_entry(struct diff_options *opt, const char *prefix,
 	unsigned mode;
 	const char *path;
 	const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
-	int pathlen = tree_entry_len(path, sha1);
+	int pathlen = tree_entry_len(&desc->entry);
 	int old_baselen = base->len;
 
 	strbuf_add(base, path, pathlen);
diff --git a/tree-walk.c b/tree-walk.c
index 418107e..f5d19f9 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -116,7 +116,7 @@ void setup_traverse_info(struct traverse_info *info, const char *base)
 
 char *make_traverse_path(char *path, const struct traverse_info *info, const struct name_entry *n)
 {
-	int len = tree_entry_len(n->path, n->sha1);
+	int len = tree_entry_len(n);
 	int pathlen = info->pathlen;
 
 	path[pathlen + len] = 0;
@@ -126,7 +126,7 @@ char *make_traverse_path(char *path, const struct traverse_info *info, const str
 			break;
 		path[--pathlen] = '/';
 		n = &info->name;
-		len = tree_entry_len(n->path, n->sha1);
+		len = tree_entry_len(n);
 		info = info->prev;
 		pathlen -= len;
 	}
@@ -253,7 +253,7 @@ static void extended_entry_extract(struct tree_desc_x *t,
 	 * The caller wants "first" from this tree, or nothing.
 	 */
 	path = a->path;
-	len = tree_entry_len(a->path, a->sha1);
+	len = tree_entry_len(a);
 	switch (check_entry_match(first, first_len, path, len)) {
 	case -1:
 		entry_clear(a);
@@ -271,7 +271,7 @@ static void extended_entry_extract(struct tree_desc_x *t,
 	while (probe.size) {
 		entry_extract(&probe, a);
 		path = a->path;
-		len = tree_entry_len(a->path, a->sha1);
+		len = tree_entry_len(a);
 		switch (check_entry_match(first, first_len, path, len)) {
 		case -1:
 			entry_clear(a);
@@ -362,7 +362,7 @@ int traverse_trees(int n, struct tree_desc *t, struct traverse_info *info)
 			e = entry + i;
 			if (!e->path)
 				continue;
-			len = tree_entry_len(e->path, e->sha1);
+			len = tree_entry_len(e);
 			if (!first) {
 				first = e->path;
 				first_len = len;
@@ -381,7 +381,7 @@ int traverse_trees(int n, struct tree_desc *t, struct traverse_info *info)
 				/* Cull the ones that are not the earliest */
 				if (!e->path)
 					continue;
-				len = tree_entry_len(e->path, e->sha1);
+				len = tree_entry_len(e);
 				if (name_compare(e->path, len, first, first_len))
 					entry_clear(e);
 			}
@@ -434,8 +434,8 @@ static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char
 		int entrylen, cmp;
 
 		sha1 = tree_entry_extract(t, &entry, mode);
+		entrylen = tree_entry_len(&t->entry);
 		update_tree_entry(t);
-		entrylen = tree_entry_len(entry, sha1);
 		if (entrylen > namelen)
 			continue;
 		cmp = memcmp(name, entry, entrylen);
@@ -596,7 +596,7 @@ int tree_entry_interesting(const struct name_entry *entry,
 				      ps->max_depth);
 	}
 
-	pathlen = tree_entry_len(entry->path, entry->sha1);
+	pathlen = tree_entry_len(entry);
 
 	for (i = ps->nr - 1; i >= 0; i--) {
 		const struct pathspec_item *item = ps->items+i;
diff --git a/tree-walk.h b/tree-walk.h
index 0089581..884d01a 100644
--- a/tree-walk.h
+++ b/tree-walk.h
@@ -20,9 +20,9 @@ static inline const unsigned char *tree_entry_extract(struct tree_desc *desc, co
 	return desc->entry.sha1;
 }
 
-static inline int tree_entry_len(const char *name, const unsigned char *sha1)
+static inline int tree_entry_len(const struct name_entry *ne)
 {
-	return (const char *)sha1 - name - 1;
+	return (const char *)ne->sha1 - ne->path - 1;
 }
 
 void update_tree_entry(struct tree_desc *);
@@ -58,7 +58,7 @@ extern void setup_traverse_info(struct traverse_info *info, const char *base);
 
 static inline int traverse_path_len(const struct traverse_info *info, const struct name_entry *n)
 {
-	return info->pathlen + tree_entry_len(n->path, n->sha1);
+	return info->pathlen + tree_entry_len(n);
 }
 
 extern int tree_entry_interesting(const struct name_entry *, struct strbuf *, int, const struct pathspec *ps);
diff --git a/tree.c b/tree.c
index 698ecf7..e622198 100644
--- a/tree.c
+++ b/tree.c
@@ -99,7 +99,7 @@ static int read_tree_1(struct tree *tree, struct strbuf *base,
 		else
 			continue;
 
-		len = tree_entry_len(entry.path, entry.sha1);
+		len = tree_entry_len(&entry);
 		strbuf_add(base, entry.path, len);
 		strbuf_addch(base, '/');
 		retval = read_tree_1(lookup_tree(sha1),
diff --git a/unpack-trees.c b/unpack-trees.c
index 8282f5e..7c9ecf6 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -446,7 +446,7 @@ static int traverse_trees_recursive(int n, unsigned long dirmask,
 	newinfo.prev = info;
 	newinfo.pathspec = info->pathspec;
 	newinfo.name = *p;
-	newinfo.pathlen += tree_entry_len(p->path, p->sha1) + 1;
+	newinfo.pathlen += tree_entry_len(p) + 1;
 	newinfo.conflicts |= df_conflicts;
 
 	for (i = 0; i < n; i++, dirmask >>= 1) {
@@ -495,7 +495,7 @@ static int do_compare_entry(const struct cache_entry *ce, const struct traverse_
 	ce_len -= pathlen;
 	ce_name = ce->name + pathlen;
 
-	len = tree_entry_len(n->path, n->sha1);
+	len = tree_entry_len(n);
 	return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
 }
 
@@ -626,7 +626,7 @@ static int find_cache_pos(struct traverse_info *info,
 	struct unpack_trees_options *o = info->data;
 	struct index_state *index = o->src_index;
 	int pfxlen = info->pathlen;
-	int p_len = tree_entry_len(p->path, p->sha1);
+	int p_len = tree_entry_len(p);
 
 	for (pos = o->cache_bottom; pos < index->cache_nr; pos++) {
 		struct cache_entry *ce = index->cache[pos];
-- 
1.7.3.1.256.g2539c.dirty