shithub: riscv

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kernel: make sure user text, data and bss wont overlap the stack segment in sysexec()

--- a/sys/src/9/port/sysproc.c

+++ b/sys/src/9/port/sysproc.c

@@ -283,7 +283,7 @@

 		text = l2be(exec.text);

 		entry = l2be(exec.entry);

 		if(n==sizeof(Exec) && (magic == AOUT_MAGIC)){

-			if(text >= USTKTOP-UTZERO

+			if(text >= (USTKTOP-USTKSIZE)-(UTZERO+sizeof(Exec))

 			|| entry < UTZERO+sizeof(Exec)

 			|| entry >= UTZERO+sizeof(Exec)+text)

 				error(Ebadexec);

@@ -322,7 +322,7 @@

 	d = (t + data + (BY2PG-1)) & ~(BY2PG-1);

 	bssend = t + data + bss;

 	b = (bssend + (BY2PG-1)) & ~(BY2PG-1);

-	if(t >= KZERO || d >= KZERO || b >= KZERO)

+	if(t >= (USTKTOP-USTKSIZE) || d >= (USTKTOP-USTKSIZE) || b >= (USTKTOP-USTKSIZE))

 		error(Ebadexec);

 	/*

-- 

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