Add `printf` hardening

3 files changed, 20 insertions, 0 deletions

diff --git a/include/stdio.h b/include/stdio.h
index b407d0f..c363edc 100644
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -38,6 +38,7 @@ extern "C" {
 #undef popen
 #undef vsnprintf
 #undef vsprintf
+#undef printf
 
 __access(read_only, 2)
 #if __has_builtin(__builtin_fdopen)
@@ -241,6 +242,17 @@ _FORTIFY_FN(sprintf) int sprintf(char *__s, const char *__f, ...)
 #endif
 }
 
+__format(printf, 1, 2)
+__access(read_only, 1)
+_FORTIFY_FN(printf) int printf(const char *__f, ...)
+{
+#if __has_builtin(__builtin___printf_chk) && USE_NATIVE_CHK
+        return __builtin___printf_chk(_FORTIFY_SOURCE, __f, __builtin_va_arg_pack());
+#else
+        return __orig_printf(__f, __builtin_va_arg_pack());
+#endif
+}
+
 #endif /* __has_builtin(__builtin_va_arg_pack) */
 
 #ifdef __cplusplus
diff --git a/tests/Makefile b/tests/Makefile
index 4e5ee00..a628a2a 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -64,6 +64,7 @@ RUNTIME_TARGETS= \
         test_ppoll_static            \
         test_pread_dynamic           \
         test_pread_static            \
+        test_printf                  \
         test_pwrite_dynamic          \
         test_pwrite_static           \
         test_read_dynamic            \
diff --git a/tests/test_printf.c b/tests/test_printf.c
new file mode 100644
index 0000000..d444a52
--- /dev/null
+++ b/tests/test_printf.c
@@ -0,0 +1,7 @@
+#include "common.h"
+
+#include <stdio.h>
+
+int main(int argc, char** argv) {
+  printf("%s", "1234567");
+}