ipsec_xvalid: clear scratch SIMD registers after setting patterns

The cross validation tool sets patterns in buffers to search
for leftover sensitive data in various memory areas.
These patterns might be stored in SIMD registers, which might
be stored in stack when submitting jobs or expanding keys.
To avoid this problem, scratch SIMD registers are cleared
before calling the Multi Buffer API.

Change-Id: I304c04e21feba48f91c8cf34e4d047e9be17289a

LibTestApp/ipsec_xvalid.c

@@ -1133,6 +1133,29 @@ perform_safe_checks(MB_MGR *mgr, const enum arch_type_e arch,
         return 0;
 }
 
+static void
+clear_scratch_simd(const enum arch_type_e arch)
+{
+        switch (arch) {
+        case ARCH_SSE:
+        case ARCH_AESNI_EMU:
+                clear_scratch_xmms_sse();
+                break;
+        case ARCH_AVX:
+                clear_scratch_xmms_avx();
+                break;
+        case ARCH_AVX2:
+                clear_scratch_ymms();
+                break;
+        case ARCH_AVX512:
+                clear_scratch_zmms();
+                break;
+        default:
+                fprintf(stderr, "Invalid architecture\n");
+                exit(EXIT_FAILURE);
+        }
+}
+
 /* Performs test using AES_HMAC or DOCSIS */
 static int
 do_test(MB_MGR *enc_mb_mgr, const enum arch_type_e enc_arch,
@@ -1203,6 +1226,9 @@ do_test(MB_MGR *enc_mb_mgr, const enum arch_type_e enc_arch,
         if (safe_check) {
                 uint8_t *rsp_ptr;
 
+                /* Clear scratch registers before expanding keys to prevent
+                 * other functions from storing sensitive data in stack */
+                clear_scratch_simd(enc_arch);
                 if (prepare_keys(enc_mb_mgr, enc_keys, key, params, 0) < 0)
                         goto exit;
 
@@ -1252,6 +1278,10 @@ do_test(MB_MGR *enc_mb_mgr, const enum arch_type_e enc_arch,
                 /* Randomize memory for input digest */
                 generate_random_buf(in_digest, tag_size);
 
+                /* Clear scratch registers before submitting job to prevent
+                 * other functions from storing sensitive data in stack */
+                if (safe_check)
+                        clear_scratch_simd(enc_arch);
                 job = IMB_SUBMIT_JOB(enc_mb_mgr);
 
                 if (!job)
@@ -1294,6 +1324,10 @@ do_test(MB_MGR *enc_mb_mgr, const enum arch_type_e enc_arch,
                              buf_size, tag_size, DECRYPT, dec_keys, iv) < 0)
                         goto exit;
 
+                /* Clear scratch registers before submitting job to prevent
+                 * other functions from storing sensitive data in stack */
+                if (safe_check)
+                        clear_scratch_simd(dec_arch);
                 job = IMB_SUBMIT_JOB(dec_mb_mgr);
 
                 if (!job)

LibTestApp/misc.asm

@@ -134,3 +134,118 @@ dump_zmms:
 %endrep
 
         ret
+
+;
+; This function clears all scratch XMM registers
+;
+; void clear_scratch_xmms_sse(void)
+MKGLOBAL(clear_scratch_xmms_sse,function,internal)
+clear_scratch_xmms_sse:
+
+%ifdef LINUX
+%assign i 0
+%rep 16
+        pxor    xmm %+ i, xmm %+ i
+%assign i (i+1)
+%endrep
+; On Windows, XMM0-XMM5 registers are scratch registers
+%else
+%assign i 0
+%rep 6
+        pxor    xmm %+ i, xmm %+ i
+%assign i (i+1)
+%endrep
+%endif ; LINUX
+
+        ret
+
+;
+; This function clears all scratch XMM registers
+;
+; It should be called before restoring the XMM registers
+; for Windows (XMM6-XMM15)
+;
+; void clear_scratch_xmms_avx(void)
+MKGLOBAL(clear_scratch_xmms_avx,function,internal)
+clear_scratch_xmms_avx:
+
+%ifdef LINUX
+        vzeroall
+; On Windows, XMM0-XMM5 registers are scratch registers
+%else
+%assign i 0
+%rep 6
+        vpxor   xmm %+ i, xmm %+ i
+%assign i (i+1)
+%endrep
+%endif ; LINUX
+
+        ret
+
+;
+; This function clears all scratch YMM registers
+;
+; It should be called before restoring the XMM registers
+; for Windows (XMM6-XMM15)
+;
+; void clear_scratch_ymms(void)
+MKGLOBAL(clear_scratch_ymms,function,internal)
+clear_scratch_ymms:
+; On Linux, all YMM registers are scratch registers
+%ifdef LINUX
+        vzeroall
+; On Windows, YMM0-YMM5 registers are scratch registers.
+; YMM6-YMM15 upper 128 bits are scratch registers too, but
+; the lower 128 bits are to be restored after calling these function
+; which clears the upper bits too.
+%else
+%assign i 0
+%rep 6
+        vpxor   ymm %+ i, ymm %+ i
+%assign i (i+1)
+%endrep
+%endif ; LINUX
+
+        ret
+
+;
+; This function clears all scratch ZMM registers
+;
+; It should be called before restoring the XMM registers
+; for Windows (XMM6-XMM15). YMM registers are used
+; on purpose, since XOR'ing YMM registers is faster
+; than XOR'ing ZMM registers, and the operation clears
+; also the upper 256 bits
+;
+; void clear_scratch_zmms(void)
+MKGLOBAL(clear_scratch_zmms,function,internal)
+clear_scratch_zmms:
+
+; On Linux, all ZMM registers are scratch registers
+%ifdef LINUX
+        vzeroall
+        ;; vzeroall only clears the first 16 ZMM registers
+%assign i 16
+%rep 16
+        vpxorq  ymm %+ i, ymm %+ i
+%assign i (i+1)
+%endrep
+; On Windows, ZMM0-ZMM5 and ZMM16-ZMM31 registers are scratch registers.
+; ZMM6-ZMM15 upper 384 bits are scratch registers too, but
+; the lower 128 bits are to be restored after calling these function
+; which clears the upper bits too.
+%else
+%assign i 0
+%rep 6
+        vpxorq  ymm %+ i, ymm %+ i
+%assign i (i+1)
+%endrep
+
+%assign i 16
+%rep 16
+        vpxorq  ymm %+ i, ymm %+ i
+%assign i (i+1)
+%endrep
+%endif ; LINUX
+
+        ret

LibTestApp/misc.h

@@ -49,4 +49,10 @@ void dump_xmms_avx(void);
 void dump_ymms(void);
 void dump_zmms(void);
 
+/* Functions to clear all scratch SIMD registers */
+void clear_scratch_xmms_sse(void);
+void clear_scratch_xmms_avx(void);
+void clear_scratch_ymms(void);
+void clear_scratch_zmms(void);
+
 #endif /* XVALIDAPP_MISC_H */