Add bounds check to __libc_ifunc_impl_list

Add a proper bounds check to __libc_ifunc_impl_list. This makes MAX_IFUNC
redundant and fixes several targets that will write outside the array.
To avoid unnecessary large diffs, pass the maximum in the argument 'i' to
IFUNC_IMPL_ADD - 'max' can be used in new ifunc definitions and existing
ones can be updated if desired.

Passes buildmanyglibc.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/include/ifunc-impl-list.h b/include/ifunc-impl-list.h
index 78087f015c..00bf48f3f1 100644
--- a/include/ifunc-impl-list.h
+++ b/include/ifunc-impl-list.h
@@ -34,15 +34,15 @@ struct libc_ifunc_impl
 
 /* Add an IFUNC implementation, IMPL, for function FUNC, to ARRAY with
    USABLE at index I and advance I by one.  */
-#define IFUNC_IMPL_ADD(array, i, func, usable, impl) \
+#define IFUNC_IMPL_ADD(array, max, func, usable, impl) \
   extern __typeof (func) impl attribute_hidden; \
-  (array)[i++] = (struct libc_ifunc_impl) { #impl, (void (*) (void)) impl, (usable) };
+  if (n < max) (array)[n++] = (struct libc_ifunc_impl) { #impl, (void (*) (void)) impl, (usable) };
 
 /* Return the number of IFUNC implementations, N, for function FUNC if
    string NAME matches FUNC.  */
-#define IFUNC_IMPL(n, name, func, ...) \
+#define IFUNC_IMPL(max, name, func, ...) \
   if (strcmp (name, #func) == 0) \
-    { \
+    { size_t n = 0;\
       __VA_ARGS__; \
       return n; \
     }