Merge branch 'jk/path-name-safety-2.4' into maint-2.4

Bugfix patches were backported from the 'master' front to plug heap
corruption holes, to catch integer overflow in the computation of
pathname lengths, and to get rid of the name_path API.  Both of
these would have resulted in writing over an under-allocated buffer
when formulating pathnames while tree traversal.

* jk/path-name-safety-2.4:
  list-objects: pass full pathname to callbacks
  list-objects: drop name_path entirely
  list-objects: convert name_path to a strbuf
  show_object_with_name: simplify by using path_name()
  http-push: stop using name_path
  tree-diff: catch integer overflow in combine_diff_path allocation
  add helpers for detecting size_t overflow

1 files changed, 34 insertions, 0 deletions

diff --git a/git-compat-util.h b/git-compat-util.h
index af5af22680..061e33c774 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -96,6 +96,14 @@
 #define unsigned_add_overflows(a, b) \
     ((b) > maximum_unsigned_value_of_type(a) - (a))
 
+/*
+ * Returns true if the multiplication of "a" and "b" will
+ * overflow. The types of "a" and "b" must match and must be unsigned.
+ * Note that this macro evaluates "a" twice!
+ */
+#define unsigned_mult_overflows(a, b) \
+    ((a) && (b) > maximum_unsigned_value_of_type(a) / (a))
+
 #ifdef __GNUC__
 #define TYPEOF(x) (__typeof__(x))
 #else
@@ -698,6 +706,32 @@ extern void release_pack_memory(size_t);
 typedef void (*try_to_free_t)(size_t);
 extern try_to_free_t set_try_to_free_routine(try_to_free_t);
 
+static inline size_t st_add(size_t a, size_t b)
+{
+	if (unsigned_add_overflows(a, b))
+		die("size_t overflow: %"PRIuMAX" + %"PRIuMAX,
+		    (uintmax_t)a, (uintmax_t)b);
+	return a + b;
+}
+#define st_add3(a,b,c)   st_add((a),st_add((b),(c)))
+#define st_add4(a,b,c,d) st_add((a),st_add3((b),(c),(d)))
+
+static inline size_t st_mult(size_t a, size_t b)
+{
+	if (unsigned_mult_overflows(a, b))
+		die("size_t overflow: %"PRIuMAX" * %"PRIuMAX,
+		    (uintmax_t)a, (uintmax_t)b);
+	return a * b;
+}
+
+static inline size_t st_sub(size_t a, size_t b)
+{
+	if (a < b)
+		die("size_t underflow: %"PRIuMAX" - %"PRIuMAX,
+		    (uintmax_t)a, (uintmax_t)b);
+	return a - b;
+}
+
 #ifdef HAVE_ALLOCA_H
 # include <alloca.h>
 # define xalloca(size)      (alloca(size))