Tune the paranoia down a bit

size_t is guaranteed to be large enough to measure the size of things in
memory, so when doing exactely that (e.g. strlen(a) + strlen(b)), checking
for overflow is pointless since both objects are already in memory. If the
addition would overflow, the two strings would occupy more memory than
addressable.

(Possible exception being some kind of harward style architecture with
the two strings being in different kinds of memory of course.)

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

2 files changed, 4 insertions, 21 deletions

diff --git a/lib/fstree/fstree_from_dir.c b/lib/fstree/fstree_from_dir.c
index d6fac86..9aab5df 100644
--- a/lib/fstree/fstree_from_dir.c
+++ b/lib/fstree/fstree_from_dir.c
@@ -25,7 +25,6 @@
 static char *get_file_path(tree_node_t *n, const char *name)
 {
 	char *ptr, *new;
-	size_t len;
 	int ret;
 
 	if (n->parent == NULL) {
@@ -42,13 +41,7 @@ static char *get_file_path(tree_node_t *n, const char *name)
 	ret = canonicalize_name(ptr);
 	assert(ret == 0);
 
-	if (SZ_ADD_OV(strlen(ptr), strlen(name), &len) ||
-	    SZ_ADD_OV(len, 2, &len)) {
-		errno = EOVERFLOW;
-		goto fail;
-	}
-
-	new = realloc(ptr, len);
+	new = realloc(ptr, strlen(ptr) + strlen(name) + 2);
 	if (new == NULL)
 		goto fail;
 
diff --git a/lib/fstree/get_path.c b/lib/fstree/get_path.c
index f464ade..decf92e 100644
--- a/lib/fstree/get_path.c
+++ b/lib/fstree/get_path.c
@@ -7,11 +7,9 @@
 #include "config.h"
 
 #include "fstree.h"
-#include "util.h"
 
 #include <string.h>
 #include <stdlib.h>
-#include <errno.h>
 
 char *fstree_get_path(tree_node_t *node)
 {
@@ -23,19 +21,14 @@ char *fstree_get_path(tree_node_t *node)
 		return strdup("/");
 
 	for (it = node; it != NULL && it->parent != NULL; it = it->parent) {
-		if (SZ_ADD_OV(len, strlen(it->name), &len) ||
-		    SZ_ADD_OV(len, 1, &len))
-			goto fail_ov;
+		len += strlen(it->name) + 1;
 	}
 
-	if (SZ_ADD_OV(len, 1, &len))
-		goto fail_ov;
-
-	str = malloc(len);
+	str = malloc(len + 1);
 	if (str == NULL)
 		return NULL;
 
-	ptr = str + len - 1;
+	ptr = str + len;
 	*ptr = '\0';
 
 	for (it = node; it != NULL && it->parent != NULL; it = it->parent) {
@@ -47,7 +40,4 @@ char *fstree_get_path(tree_node_t *node)
 	}
 
 	return str;
-fail_ov:
-	errno = EOVERFLOW;
-	return NULL;
 }