[src/trunk]: src/usr.bin/grep Fix asan heap buffer overflow. from enh at google.

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/f56bf5916c08
branches:  trunk
changeset: 998020:f56bf5916c08
user:      christos <christos%NetBSD.org@localhost>
date:      Fri Apr 05 13:34:41 2019 +0000

description:
Fix asan heap buffer overflow. from enh at google.

diffstat:

 usr.bin/grep/file.c |  33 ++++++++++++++++++---------------
 1 files changed, 18 insertions(+), 15 deletions(-)

diffs (97 lines):

diff -r f192b273f36f -r f56bf5916c08 usr.bin/grep/file.c
--- a/usr.bin/grep/file.c       Fri Apr 05 12:16:13 2019 +0000
+++ b/usr.bin/grep/file.c       Fri Apr 05 13:34:41 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: file.c,v 1.10 2018/08/12 09:03:21 christos Exp $       */
+/*     $NetBSD: file.c,v 1.11 2019/04/05 13:34:41 christos Exp $       */
 /*     $FreeBSD: head/usr.bin/grep/file.c 211496 2010-08-19 09:28:59Z des $    */
 /*     $OpenBSD: file.c,v 1.11 2010/07/02 20:48:48 nicm Exp $  */
 
@@ -35,7 +35,7 @@
 #endif
 
 #include <sys/cdefs.h>
-__RCSID("$NetBSD: file.c,v 1.10 2018/08/12 09:03:21 christos Exp $");
+__RCSID("$NetBSD: file.c,v 1.11 2019/04/05 13:34:41 christos Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
@@ -63,7 +63,7 @@
 static BZFILE* bzbufdesc;
 #endif
 
-static unsigned char buffer[MAXBUFSIZ];
+static unsigned char buffer[MAXBUFSIZ + 1];
 static unsigned char *bufpos;
 static size_t bufrem;
 
@@ -128,7 +128,7 @@
        return (0);
 }
 
-static inline int
+static inline void
 grep_lnbufgrow(size_t newlen)
 {
 
@@ -136,15 +136,19 @@
                lnbuf = grep_realloc(lnbuf, newlen);
                lnbuflen = newlen;
        }
+}
 
-       return (0);
+static void
+grep_copyline(size_t off, size_t len)
+{
+       memcpy(lnbuf + off, bufpos, len);
+       lnbuf[off + len] = '\0';
 }
 
 char *
 grep_fgetln(struct file *f, size_t *lenp)
 {
        unsigned char *p;
-       char *ret;
        size_t len;
        size_t off;
        ptrdiff_t diff;
@@ -162,20 +166,20 @@
        /* Look for a newline in the remaining part of the buffer */
        if ((p = memchr(bufpos, line_sep, bufrem)) != NULL) {
                ++p; /* advance over newline */
-               ret = (char *)bufpos;
                len = p - bufpos;
+               grep_lnbufgrow(len + 1);
+               grep_copyline(0, len);
+               *lenp = len;
                bufrem -= len;
                bufpos = p;
-               *lenp = len;
-               return (ret);
+               return (char *)lnbuf;
        }
 
        /* We have to copy the current buffered data to the line buffer */
        for (len = bufrem, off = 0; ; len += bufrem) {
                /* Make sure there is room for more data */
-               if (grep_lnbufgrow(len + LNBUFBUMP))
-                       goto error;
-               memcpy(lnbuf + off, bufpos, len - off);
+               grep_lnbufgrow(len + LNBUFBUMP);
+               grep_copyline(off, len - off);
                off = len;
                if (grep_refill(f) != 0)
                        goto error;
@@ -188,9 +192,8 @@
                ++p;
                diff = p - bufpos;
                len += diff;
-               if (grep_lnbufgrow(len))
-                   goto error;
-               memcpy(lnbuf + off, bufpos, diff);
+               grep_lnbufgrow(len + 1);
+               grep_copyline(off, diff);
                bufrem -= diff;
                bufpos = p;
                break;