From c920d0da9c8a9ebdcc6c94acf98eda8d975f3e15 Mon Sep 17 00:00:00 2001
From: Rob Swindell <rob@synchro.net>
Date: Wed, 2 Mar 2022 10:06:20 -0800
Subject: [PATCH] Fix possible negative offset to lseek()
CID 327965
---
src/sbbs3/js_file.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)
diff --git a/src/sbbs3/js_file.c b/src/sbbs3/js_file.c
index 6df0610a5d..d7b84c5c06 100644
--- a/src/sbbs3/js_file.c
+++ b/src/sbbs3/js_file.c
@@ -406,15 +406,18 @@ js_raw_read(JSContext *cx, uintN argc, jsval *arglist)
* required by POSIX.
*/
fflush(p->fp);
- pos = ftell(p->fp);
- fd = fileno(p->fp);
- lseek(fd, pos, SEEK_SET);
- len = read(fileno(p->fp),buf,len);
- fseeko(p->fp, pos + (len >= 0 ? len : 0), SEEK_SET);
- dbprintf(FALSE, p, "read %u raw bytes",len);
- if(len<0)
- len=0;
-
+ pos = ftello(p->fp);
+ if(pos < 0)
+ len = 0;
+ else {
+ fd = fileno(p->fp);
+ lseek(fd, pos, SEEK_SET);
+ len = read(fileno(p->fp),buf,len);
+ fseeko(p->fp, pos + (len >= 0 ? len : 0), SEEK_SET);
+ dbprintf(FALSE, p, "read %d raw bytes",len);
+ if(len<0)
+ len=0;
+ }
JS_RESUMEREQUEST(cx, rc);
str = JS_NewStringCopyN(cx, buf, len);
--
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