performance(sqlcipher): Fix burn_stack performance issue

Implements a cross-platform version of https://github.com/OP-TEE/optee_os/pull/3102

1. Remove recursion
2. Use memset instead of while loop

go.mod

@@ -10,6 +10,8 @@ replace github.com/nfnt/resize => github.com/status-im/resize v0.0.0-20201215164
 
 replace github.com/forPelevin/gomoji => github.com/status-im/gomoji v1.1.3-0.20220213022530-e5ac4a8732d4
 
+replace github.com/mutecomm/go-sqlcipher v0.0.0-20190227152316-55dbde17881f => github.com/status-im/go-sqlcipher v0.1.0-status.1
+
 require (
 	github.com/anacrolix/torrent v1.41.0
 	github.com/beevik/ntp v0.3.0

go.sum

@@ -1551,8 +1551,6 @@ github.com/multiformats/go-varint v0.0.7 h1:sWSGR+f/eu5ABZA2ZpYKBILXTTs9JWpdEM/n
 github.com/multiformats/go-varint v0.0.7/go.mod h1:r8PUYw/fD/SjBCiKOoDlGF6QawOELpZAu9eioSos/OU=
 github.com/munnerz/goautoneg v0.0.0-20120707110453-a547fc61f48d/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
-github.com/mutecomm/go-sqlcipher v0.0.0-20190227152316-55dbde17881f h1:hd3r+uv9DNLScbOrnlj82rBldHQf3XWmCeXAWbw8euQ=
-github.com/mutecomm/go-sqlcipher v0.0.0-20190227152316-55dbde17881f/go.mod h1:MyUWrZlB1aI5bs7j9/pJ8ckLLZ4QcCYcNiSbsAW32D4=
 github.com/mutecomm/go-sqlcipher/v4 v4.4.0/go.mod h1:PyN04SaWalavxRGH9E8ZftG6Ju7rsPrGmQRjrEaVpiY=
 github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
 github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
@@ -1993,6 +1991,8 @@ github.com/status-im/go-ethereum v1.10.25-status.6 h1:5YC8k1inTBqA6LpON0uX6y86ni
 github.com/status-im/go-ethereum v1.10.25-status.6/go.mod h1:Dt4K5JYMhJRdtXJwBEyGZLZn9iz/chSOZyjVmt5ZhwQ=
 github.com/status-im/go-multiaddr-ethv4 v1.2.4 h1:7fw0Y48TJXEqx4fOHlDOUiM/uBq9zG5w4x975Mjh4E0=
 github.com/status-im/go-multiaddr-ethv4 v1.2.4/go.mod h1:PDh4D7h5CvecPIy0ji0rLNwTnzzEcyz9uTPHD42VyH4=
+github.com/status-im/go-sqlcipher v0.1.0-status.1 h1:5fkuM4FG3G5o754zFO9xErATxeig9pww+Nr6sVTUN4o=
+github.com/status-im/go-sqlcipher v0.1.0-status.1/go.mod h1:MyUWrZlB1aI5bs7j9/pJ8ckLLZ4QcCYcNiSbsAW32D4=
 github.com/status-im/gomoji v1.1.3-0.20220213022530-e5ac4a8732d4 h1:CtobZoiNdHpx+xurFxnuJ1xsGm3oKMfcZkB3vmomJmA=
 github.com/status-im/gomoji v1.1.3-0.20220213022530-e5ac4a8732d4/go.mod h1:hmpnZzkzSZJbFYWAUkrPV8I36x7mdYiPhPqnALP4fKA=
 github.com/status-im/keycard-go v0.0.0-20190316090335-8537d3370df4/go.mod h1:RZLeN1LMWmRsyYjvAu+I6Dm9QmlDaIIt+Y+4Kd7Tp+Q=

vendor/github.com/mutecomm/go-sqlcipher/burn_stack.c

@@ -21,10 +21,8 @@
 */
 void burn_stack(unsigned long len)
 {
-   unsigned char buf[32];
+   unsigned char buf[len];
    zeromem(buf, sizeof(buf));
-   if (len > (unsigned long)sizeof(buf))
-      burn_stack(len - sizeof(buf));
 }
 
 

vendor/github.com/mutecomm/go-sqlcipher/zeromem.c

@@ -9,12 +9,22 @@
  * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
  */
 #include "tomcrypt.h"
+#include <string.h>
 
 /**
    @file zeromem.c
    Zero a block of memory, Tom St Denis
 */
 
+/*
+ * Pointer to memset is volatile so that compiler must de-reference
+ * the pointer and can't assume that it points to any function in
+ * particular (such as memset, which it then might further "optimize")
+ */
+typedef void *(*memset_t)(void *, int, size_t);
+
+static volatile memset_t memset_func = memset;
+
 /**
    Zero a block of memory
    @param out    The destination of the area to zero
@@ -22,11 +32,8 @@
 */
 void zeromem(void *out, size_t outlen)
 {
-   unsigned char *mem = out;
    LTC_ARGCHKVD(out != NULL);
-   while (outlen-- > 0) {
+   memset_func((void *)out, 0, outlen);
-      *mem++ = 0;
-   }
 }
 
 /* $Source$ */

vendor/modules.txt

@@ -652,7 +652,7 @@ github.com/multiformats/go-multistream
 # github.com/multiformats/go-varint v0.0.7
 ## explicit; go 1.18
 github.com/multiformats/go-varint
-# github.com/mutecomm/go-sqlcipher v0.0.0-20190227152316-55dbde17881f
+# github.com/mutecomm/go-sqlcipher v0.0.0-20190227152316-55dbde17881f => github.com/status-im/go-sqlcipher v0.1.0-status.1
 ## explicit; go 1.12
 github.com/mutecomm/go-sqlcipher
 # github.com/nfnt/resize v0.0.0-00010101000000-000000000000 => github.com/status-im/resize v0.0.0-20201215164250-7c6d9f0d3088