[src/trunk]: src/sbin/fsck_msdos PR/44529: Martin Danielsson: fsck_msdos cras...

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

details:   https://anonhg.NetBSD.org/src/rev/739d4866277d
branches:  trunk
changeset: 761784:739d4866277d
user:      christos <christos%NetBSD.org@localhost>
date:      Mon Feb 07 17:36:42 2011 +0000

description:
PR/44529: Martin Danielsson: fsck_msdos crashes when verifying corrupt file
system. Avoid using the long name index when it is 0. Refactor the code to
avoid duplication.

diffstat:

 sbin/fsck_msdos/dir.c |  85 +++++++++++++++++++++++++++------------------------
 1 files changed, 45 insertions(+), 40 deletions(-)

diffs (143 lines):

diff -r 2b8c7c2e537f -r 739d4866277d sbin/fsck_msdos/dir.c
--- a/sbin/fsck_msdos/dir.c     Mon Feb 07 15:58:35 2011 +0000
+++ b/sbin/fsck_msdos/dir.c     Mon Feb 07 17:36:42 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: dir.c,v 1.23 2009/04/11 07:14:50 lukem Exp $   */
+/*     $NetBSD: dir.c,v 1.24 2011/02/07 17:36:42 christos Exp $        */
 
 /*
  * Copyright (C) 1995, 1996, 1997 Wolfgang Solfrank
@@ -30,7 +30,7 @@
 
 #include <sys/cdefs.h>
 #ifndef lint
-__RCSID("$NetBSD: dir.c,v 1.23 2009/04/11 07:14:50 lukem Exp $");
+__RCSID("$NetBSD: dir.c,v 1.24 2011/02/07 17:36:42 christos Exp $");
 #endif /* not lint */
 
 #include <stdio.h>
@@ -204,6 +204,7 @@
  * Global variables temporarily used during a directory scan
  */
 static char longName[DOSLONGNAMELEN] = "";
+static char *eLongName = longName + sizeof(longName);
 static u_char *buffer = NULL;
 static u_char *delbuf = NULL;
 
@@ -432,6 +433,26 @@
        return FSOK;
 }
 
+static int
+procName(int from, int to, char **dst, const u_char *src)
+{
+       int k;
+       char *t = *dst;
+
+       for (k = from; k < to && t < eLongName; k += 2) {
+               if (!src[k] && !src[k + 1])
+                       break;
+               *t++ = src[k];
+               /*
+                * Warn about those unusable chars in msdosfs here?     XXX
+                */
+               if (src[k + 1])
+                   t[-1] = '?';
+       }
+       *dst = t;
+       return k;
+}
+
 /*
  * Read a directory and
  *   - resolve long name records
@@ -526,6 +547,7 @@
                        }
 
                        if (p[11] == ATTR_WIN95) {
+                               u_int lrnomask = *p & LRNOMASK;
                                if (*p & LRFIRST) {
                                        if (shortSum != -1) {
                                                if (!invlfn) {
@@ -538,7 +560,7 @@
                                        vallfn = p;
                                        valcl = cl;
                                } else if (shortSum != p[13]
-                                          || lidx != (*p & LRNOMASK)) {
+                                  || lidx != lrnomask || lrnomask != 0) {
                                        if (!invlfn) {
                                                invlfn = vallfn;
                                                invcl = valcl;
@@ -549,52 +571,35 @@
                                        }
                                        vallfn = NULL;
                                }
-                               lidx = *p & LRNOMASK;
-                               t = longName + --lidx * 13;
-                               for (k = 1; k < 11 && t < longName + sizeof(longName); k += 2) {
-                                       if (!p[k] && !p[k + 1])
-                                               break;
-                                       *t++ = p[k];
-                                       /*
-                                        * Warn about those unusable chars in msdosfs here?     XXX
-                                        */
-                                       if (p[k + 1])
-                                               t[-1] = '?';
-                               }
-                               if (k >= 11)
-                                       for (k = 14; k < 26 && t < longName + sizeof(longName); k += 2) {
-                                               if (!p[k] && !p[k + 1])
-                                                       break;
-                                               *t++ = p[k];
-                                               if (p[k + 1])
-                                                       t[-1] = '?';
+                               lidx = lrnomask;
+                               if (lidx != 0) {
+                                       t = longName + --lidx * 13;
+                                       k = procName(1, 11, &t, p);
+                                       if (k >= 11)
+                                               k = procName(14, 26, &t, p);
+                                       if (k >= 26)
+                                               k = procName(28, 32, &t, p);
+                                       if (t >= eLongName) {
+                                               pwarn(
+                                                   "long filename too long\n");
+                                               if (!invlfn) {
+                                                       invlfn = vallfn;
+                                                       invcl = valcl;
+                                               }
+                                               vallfn = NULL;
                                        }
-                               if (k >= 26)
-                                       for (k = 28; k < 32 && t < longName + sizeof(longName); k += 2) {
-                                               if (!p[k] && !p[k + 1])
-                                                       break;
-                                               *t++ = p[k];
-                                               if (p[k + 1])
-                                                       t[-1] = '?';
-                                       }
-                               if (t >= longName + sizeof(longName)) {
-                                       pwarn("long filename too long\n");
-                                       if (!invlfn) {
-                                               invlfn = vallfn;
-                                               invcl = valcl;
-                                       }
-                                       vallfn = NULL;
                                }
                                if (p[26] | (p[27] << 8)) {
-                                       pwarn("long filename record cluster start != 0\n");
+                                       pwarn("long filename record cluster "
+                                           "start != 0\n");
                                        if (!invlfn) {
                                                invlfn = vallfn;
                                                invcl = cl;
                                        }
                                        vallfn = NULL;
                                }
-                               continue;       /* long records don't carry further
-                                                * information */
+                               continue;       /* long records don't carry
+                                                * further information */
                        }
 
                        /*