From f2466297885cfdd3424033139d5aa14065791b84 Mon Sep 17 00:00:00 2001
From: rsc <devnull@localhost>
Date: Thu, 4 May 2006 19:10:11 +0000
Subject: paranoia about extension

---
 src/cmd/9pserve.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

(limited to 'src')

diff --git a/src/cmd/9pserve.c b/src/cmd/9pserve.c
index 623b966a..3693164b 100644
--- a/src/cmd/9pserve.c
+++ b/src/cmd/9pserve.c
@@ -10,7 +10,8 @@ enum
 {
 	STACK = 32768,
 	NHASH = 31,
-	MAXMSG = 64	/* per connection */
+	MAXMSG = 64,	/* per connection */
+	MAXMSGSIZE = 4*1024*1024
 };
 
 typedef struct Hash Hash;
@@ -231,6 +232,8 @@ mainproc(void *v)
 		if(n != nn)
 			sysfatal("error writing Tversion: %r\n");
 		n = read9pmsg(0, vbuf, sizeof vbuf);
+		if(n < 0)
+			sysfatal("read9pmsg failure"):
 		if(convM2S(vbuf, n, &f) != n)
 			sysfatal("convM2S failure");
 		if(f.msize < msize)
@@ -1220,6 +1223,8 @@ read9ppkt(Ioproc *io, int fd)
 	if(n != 4)
 		return nil;
 	n = GBIT32(buf);
+	if(n > MAXMSGSIZE)
+		return nil;
 	pkt = emalloc(n);
 	PBIT32(pkt, n);
 	nn = ioreadn(io, fd, pkt+4, n-4);
-- 
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