Add vasprintf/asprintf2.3

The only hardening being done here is to set the char** parameter to thos
functions to NULL in case of an error, to prevent it from being used should
people forget to check return values. This is already done on some BSD, as well
as in Rocky Linux.

5 files changed, 105 insertions, 3 deletions

diff --git a/README.md b/README.md
index 9b9a956..f47df41 100644
--- a/README.md
+++ b/README.md
@@ -59,6 +59,7 @@ At this point, the program will safely crash.
 
 - `FD_CLR`
 - `FD_SET`
+- `asprintf`
 - `bcopy`
 - `bzero`
 - `calloc`
@@ -121,6 +122,7 @@ At this point, the program will safely crash.
 - `umask` 
 - `vfprintf` 
 - `vprintf` 
+- `vasprintf`
 - `vsnprintf`
 - `vsprintf`
 - `wcrtomb`
diff --git a/include/stdio.h b/include/stdio.h
index c6817fa..abdef6c 100644
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -220,6 +220,26 @@ _FORTIFY_FN(vprintf) int vprintf(const char *__f, __builtin_va_list __v)
         return __orig_vprintf(__f, __v);
 #endif
 }
+
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+#undef vasprintf
+#if __has_builtin(__builtin_vasprintf)
+__diagnose_as_builtin(__builtin_vasprintf, 1, 2, 3)
+#endif
+_FORTIFY_FN(vasprintf) int vasprintf(char **restrict strp, const char *restrict fmt, __builtin_va_list ap)
+{
+#if __has_builtin(__builtin___vasprintf_chk) && USE_NATIVE_CHK
+        return __builtin___vasprintf_chk(_FORTIFY_SOURCE, strp, fmt, ap);
+#else
+        int ret = __orig_vasprintf(strp, fmt, ap);
+        if (ret < 0)
+                *strp = NULL;
+        return ret;
+#endif
+}
+
+
+#endif // defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
 #endif  // __clang__
 
 
@@ -312,6 +332,28 @@ _FORTIFY_FN(fprintf) int fprintf(FILE *__s, const char *__f, ...)
 #endif
 }
 
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+#ifndef __clang__
+#undef asprintf
+__fh_access(read_only, 2)
+__fh_format(printf, 2, 0)
+#if __has_builtin(__builtin_asprintf)
+__diagnose_as_builtin(__builtin_asprintf, 2, 3)
+#endif
+_FORTIFY_FN(asprintf) int asprintf(char **restrict strp, const char *restrict fmt, ...)
+{
+#if __has_builtin(__builtin___asprintf_chk) && USE_NATIVE_CHK
+        return __builtin___asprintf_chk(_FORTIFY_SOURCE, strp, fmt, __builtin_va_arg_pack());
+#else
+        int ret = __orig_asprintf(strp, fmt, __builtin_va_arg_pack());
+        if (ret<0)
+                *strp = NULL;
+        return ret;
+#endif
+}
+#endif // __clang__
+#endif
+
 #pragma GCC diagnostic pop
 #endif /* __has_builtin(__builtin_va_arg_pack) */
 
diff --git a/tests/Makefile b/tests/Makefile
index c18898e..32b17b0 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -1,4 +1,4 @@
-CFLAGS+=-I../include/ -D_FORTIFY_SOURCE=3 -static -O2 -DPEDANTIC_CHECKS
+CFLAGS+=-I../include/ -D_FORTIFY_SOURCE=3 -static -O2 -DPEDANTIC_CHECKS -Wno-format
 
 COMPTIME_TARGETS= \
         test_memcpy_overwrite_under  \
@@ -12,6 +12,7 @@ RUNTIME_TARGETS= \
         test_FD_SET_negative         \
         test_FD_ISSET_SETSIZE        \
         test_FD_ISSET_negative       \
+        test_asprintf                \
         test_bcopy_dynamic_read      \
         test_bcopy_dynamic_write     \
         test_bcopy_static_read       \
@@ -126,11 +127,12 @@ RUNTIME_TARGETS= \
         test_ttyname_r_dynamic       \
         test_ttyname_r_static        \
         test_umask                   \
+        test_vasprintf               \
+        test_vfprintf                \
+        test_vprintf                 \
         test_vsnprintf_dynamic       \
         test_vsnprintf_static        \
         test_vsprintf                \
-        test_vfprintf                \
-        test_vprintf                 \
         test_wcscat_static_write     \
         test_wcscpy_static_write     \
         test_wcsncat_static_write    \
diff --git a/tests/test_asprintf.c b/tests/test_asprintf.c
new file mode 100644
index 0000000..a02d110
--- /dev/null
+++ b/tests/test_asprintf.c
@@ -0,0 +1,20 @@
+#define _GNU_SOURCE
+#include "common.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char** argv) {
+    char* buf;
+    asprintf(&buf, "total: %d+%d=%d", 1, 2, 3);
+    puts(buf);
+    free(buf);
+
+#ifndef __clang__
+    asprintf(&buf, "total: %", 1);
+    assert(buf == NULL);
+#endif
+
+    return 0;
+}
diff --git a/tests/test_vasprintf.c b/tests/test_vasprintf.c
new file mode 100644
index 0000000..2f71714
--- /dev/null
+++ b/tests/test_vasprintf.c
@@ -0,0 +1,36 @@
+#define _GNU_SOURCE
+#include "common.h"
+
+#include <assert.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+void test(const char *fmt, ...)
+{
+    char* buf;
+    va_list args;
+    va_start(args, fmt);
+    vasprintf(&buf, fmt, args);
+    va_end(args);
+    puts(buf);
+    free(buf);
+}
+
+void test2(const char *fmt, ...)
+{
+    char* buf;
+    va_list args;
+    va_start(args, fmt);
+    vasprintf(&buf, fmt, args);
+    va_end(args);
+    assert(buf == NULL);
+}
+
+int main(int argc, char** argv) {
+    test("Total: %d+%d=%d", 1, 2, 3);
+#ifndef __clang__
+    test2("Total: %", 1, 2, 3);
+#endif
+    return 0;
+}