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chk: whitelist some pc ranges for ok-but-sketchy asm functions

--- a/5e.c

+++ b/5e.c

@@ -7,7 +7,11 @@

 int vfp = 1;

 int nflag, pflag, bflag;

 int check;

-u32int mallocaddr, freeaddr, reallocaddr, vtraceaddr;

+u32int mallocaddr;

+u32int freeaddr;

+u32int reallocaddr;

+u32int setmalloctagaddr;

+u32int setrealloctagaddr;

 Ref nproc;

 void

@@ -132,8 +136,7 @@

 	dotext(argc, argv);

 	atnotify(notehandler, 1);

 	for(;;) {

-extern int vtrace;

-		if(ultraverbose || vtrace)

+		if(ultraverbose)

 			dump();

 		step();

 		while((P->notein - P->noteout) % NNOTE) {

--- a/arm.c

+++ b/arm.c

@@ -19,14 +19,11 @@

 	fH = 1<<5,

 };

-int vtrace;

-

 u32int mallocaddr;

 u32int freeaddr;

 u32int reallocaddr;

 u32int setmalloctagaddr;

 u32int setrealloctagaddr;

-u32int vtraceaddr;

 static u32int

 arg(int n)

@@ -348,8 +345,6 @@

 				P->hookpc = P->R[15];

 			}else if(npc == setrealloctagaddr){

 				P->hookpc = P->R[15];

-			}else if(npc == vtraceaddr){

-				vtrace = arg(0);

 			}

 		}

 	}

--- a/chk.c

+++ b/chk.c

@@ -6,6 +6,10 @@

 #include "dat.h"

 #include "fns.h"

+

+uvlong	okrange[32];

+int	nokrange;

+

 void

 dumpmap(Segment *seg, u32int off, u32int len, char *fmt, ...)

 {

@@ -22,7 +26,6 @@

 		print("not tracing\n");

 		return;

 	}

-print("off: %d, len: %d\n", off, len);

 	for(i = off/8; i <= (off+len+7)/8; i++){

 		if(i >= off/8 && i+40 < off/8)

 			c = '*';

@@ -43,6 +46,20 @@

 	return *(u32int*) vaddrnol(P->R[13] + 4 + 4 * n, 4, ARD);

 }

+static int

+okfunc(u32int pc)

+{

+	uvlong *p;

+	int i;

+

+	for(i = 0, p = okrange; i < nokrange; i += 2, p += 2)

+{print("check %#llux <= %#x <= %#llux\n", p[0], pc, p[1]);

+		if(p[0] <= pc && pc <= p[1])

+			return 1;

+}

+	return 0;

+}

+

 void

 checkaccess(Segment *seg, u32int off, u32int len, int chk)

 {

@@ -63,8 +80,8 @@

 		exits("bad access");

 	}

 	for(; off != end; off++){

-		bits = seg->shadow[off>>2] >> 2*(off&3);

-		if((bits&3) != chk){

+		bits = seg->shadow[off>>2] >> (2*(off&3));

+		if((bits&chk) != chk && !okfunc(P->R[15]-4)){

 			if(chk&MARKALLOC)

 				print("%d: access outside alloc: %#x at PC %#x\n",

 					P->pid, seg->start+off, P->R[15] - 4);

@@ -85,6 +102,7 @@

 	end = off+len;

 	if(end > seg->size)

 		end = seg->size;

+//print("valid: %#x..%#x\n", seg->start+off, seg->start+end);

 	for(; off != end; off++)

 		seg->shadow[off>>2] |= chk<<(2*(off&3));

 }

@@ -97,6 +115,7 @@

 	end = off+len;

 	if(end > seg->size)

 		end = seg->size;

+//print("invalid: %#x..%#x\n", seg->start+off, seg->start+end);

 	for(; off != end; off++)

 		seg->shadow[off>>2] &= ~(chk<<(2*(off&3)));

 }

--- a/dat.h

+++ b/dat.h

@@ -80,7 +80,8 @@

 extern u32int reallocaddr;

 extern u32int setmalloctagaddr;

 extern u32int setrealloctagaddr;

-extern u32int vtraceaddr;

+extern uvlong okrange[];

+extern int nokrange;

 enum {

 	SEGFLLOCK = 1,

--- a/proc.c

+++ b/proc.c

@@ -205,6 +205,18 @@

 	return s.value;

 }

+int

+getokrange(char *name, uvlong *bounds)

+{

+	uvlong addr;

+

+	if((addr = hookaddr(name)) == -1)

+		return 0;

+	if(fnbound(addr, bounds) == 0)

+		return 0;

+	return 2;

+}

+

 static void

 inithooks(void)

 {

@@ -213,7 +225,12 @@

 	freeaddr = hookaddr("poolfree");

 	setmalloctagaddr = hookaddr("setmalloctag");

 	setrealloctagaddr = hookaddr("setrealloctag");

-	vtraceaddr = hookaddr("vtrace");

+	nokrange += getokrange("memmove", &okrange[nokrange]);

+	nokrange += getokrange("memcpy", &okrange[nokrange]);

+	nokrange += getokrange("memset", &okrange[nokrange]);

+	nokrange += getokrange("strchr", &okrange[nokrange]);

+	nokrange += getokrange("strcmp", &okrange[nokrange]);

+	nokrange += getokrange("strcpy", &okrange[nokrange]);

 }

 int

@@ -246,7 +263,7 @@

 		markvalid(text, 0, fp.txtsz+fp.hdrsz, MARKALLOC|MARKINIT);

 		markvalid(data, 0, fp.datsz, MARKALLOC|MARKINIT);

 		markvalid(bss, 0, fp.bsssz, MARKALLOC|MARKINIT);

-		markvalid(stk, 0, stk->size, MARKALLOC|MARKINIT);

+		markvalid(stk, 0, stk->size, MARKALLOC);

 	}

 	seek(fd, fp.txtoff - fp.hdrsz, 0);

 	if(readn(fd, text->data, fp.txtsz + fp.hdrsz) < fp.txtsz + fp.hdrsz)

@@ -400,7 +417,6 @@

 void

 donote(char *msg, ulong type)

 {

-extern int vtrace;

 	int rc;

 	u32int *ureg, *sp, uregp, msgp;

 	char *msgb;

@@ -429,7 +445,7 @@

 	switch(rc = setjmp(P->notejmp) - 1) {

 	case -1:

 		for(;;) {

-			if(ultraverbose || vtrace)

+			if(ultraverbose)

 				dump();

 			step();

 		}