[vlc-devel] [PATCH] Fix Hurd build

[Samuel Thibault]

Denis Charmet, on Wed 27 Apr 2016 12:10:54 +0200, wrote:
> On 2016-04-26 21:14, Samuel Thibault wrote:
> >Rémi Denis-Courmont, on Tue 26 Apr 2016 22:12:04 +0300, wrote:
> >>I mean the following sprintf(). Maybe there was a nonobvious way to
> >>prevent
> >>overflow, but I don´t see it.
> >
> >Ok. The "idea" behind PATH_MAX is that it's supposed to be the maximum
> >size you'd want to pass with prefix and filename. But yes, that won't
> >prevent anybody from actually passing bigger filenames, and so the
> >second patch I sent, which uses malloc, just avoids the issue altogether.
> 
> I think the point of Rémi was: use snprintf and not sprintf regardless of
> your memory zone of allocation.

Then this?

>From 49ea01e4bc56d98a0c83179aa41bd1a3d35f4205 Mon Sep 17 00:00:00 2001
From: Samuel Thibault <samuel.thibault at ens-lyon.org>
Date: Tue, 26 Apr 2016 18:22:41 +0000
Subject: [PATCH] Fix hurd build

theme_loader.cpp contains an unconditional use of PATH_MAX,
which is not defined on GNU/Hurd to avoid imposing build-time
limits. This change replaces its use with dynamic allocation of the
required size.
---
 modules/gui/skins2/src/theme_loader.cpp | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/modules/gui/skins2/src/theme_loader.cpp b/modules/gui/skins2/src/theme_loader.cpp
index 1ec1dfc..6e7cb5f 100644
--- a/modules/gui/skins2/src/theme_loader.cpp
+++ b/modules/gui/skins2/src/theme_loader.cpp
@@ -549,7 +549,7 @@ int tar_extract_all( TAR *t, char *prefix )
     union tar_buffer buffer;
     int   len, err, getheader = 1, remaining = 0;
     FILE  *outfile = NULL;
-    char  fname[BLOCKSIZE + PATH_MAX];
+    char  *fname = NULL;
 
     while( 1 )
     {
@@ -566,6 +566,7 @@ int tar_extract_all( TAR *t, char *prefix )
         if( len != 0 && len != BLOCKSIZE )
         {
             fprintf( stderr, "gzread: incomplete block read\n" );
+            free( fname );
             return -1;
         }
 
@@ -583,13 +584,16 @@ int tar_extract_all( TAR *t, char *prefix )
                 break;
             }
 
-            sprintf( fname, "%s/%s", prefix, buffer.header.name );
+            size_t len = strlen(prefix) + 1 + strlen(buffer.header.name) + 1;
+            fname = (char*) malloc( len );
+            snprintf( fname, len, "%s/%s", prefix, buffer.header.name );
 
             /* Check magic value in header */
             if( strncmp( buffer.header.magic, "GNUtar", 6 ) &&
                 strncmp( buffer.header.magic, "ustar", 5 ) )
             {
                 //fprintf(stderr, "not a tar file\n");
+                free( fname );
                 return -1;
             }
 
@@ -659,6 +663,8 @@ int tar_extract_all( TAR *t, char *prefix )
         }
     }
 
+    free( fname );
+
     return 0;
 }
 
-- 
2.6.4