This is the mail archive of the libc-alpha@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH] Enforce NAME_MAX in readdir_r


On 10/12/2012 03:40 PM, Siddhesh Poyarekar wrote:
You'll need to resubmit your patch.  It reverts all of H. J.'s hard
work.

Yuck. I picked the wrong file. This should be the right one.


--
Florian Weimer / Red Hat Product Security Team
2012-10-12  Florian Weimer  <fweimer@redhat.com>

	[BZ #14699]
	* sysdeps/posix/dirstream.h (struct __dirstream): Add errcode
	member.
	* sysdeps/posix/opendir.c (__alloc_dir): Initialize errcode
	member.
	* sysdeps/posix/readdir_r.c (__READDIR_R): Enforce NAME_MAX limit.
	Return delayed error code.  Remove GETDENTS_64BIT_ALIGNED
	conditional.
	* sysdeps/unix/sysv/linux/wordsize-64/readdir_r.c: Do not define
	GETDENTS_64BIT_ALIGNED.
	* sysdeps/unix/sysv/linux/i386/readdir64_r.c: Likewise.

diff --git a/sysdeps/posix/dirstream.h b/sysdeps/posix/dirstream.h
index 6ca2904..a4ba36f 100644
--- a/sysdeps/posix/dirstream.h
+++ b/sysdeps/posix/dirstream.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 1993, 1995, 1996, 2007 Free Software Foundation, Inc.
+/* Copyright (C) 1993-2012 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -39,6 +39,8 @@ struct __dirstream
 
     off_t filepos;		/* Position of next entry to read.  */
 
+    int errcode;		/* Delayed error code.  */
+
     /* Directory block.  */
     char data[0] __attribute__ ((aligned (__alignof__ (void*))));
   };
diff --git a/sysdeps/posix/opendir.c b/sysdeps/posix/opendir.c
index e093142..a738d6c 100644
--- a/sysdeps/posix/opendir.c
+++ b/sysdeps/posix/opendir.c
@@ -1,5 +1,4 @@
-/* Copyright (C) 1991-1996,98,2000-2003,2005,2007,2009,2011
-   Free Software Foundation, Inc.
+/* Copyright (C) 1991-2012 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -223,6 +222,7 @@ __alloc_dir (int fd, bool close_fd, int flags, const struct stat64 *statp)
   dirp->size = 0;
   dirp->offset = 0;
   dirp->filepos = 0;
+  dirp->errcode = 0;
 
   return dirp;
 }
diff --git a/sysdeps/posix/readdir_r.c b/sysdeps/posix/readdir_r.c
index bfa2c0b..8db96c7 100644
--- a/sysdeps/posix/readdir_r.c
+++ b/sysdeps/posix/readdir_r.c
@@ -1,5 +1,4 @@
-/* Copyright (C) 1991,92,93,94,95,96,97,98,99,2000,02,10
-	Free Software Foundation, Inc.
+/* Copyright (C) 1991-2012 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -41,6 +40,7 @@ __READDIR_R (DIR *dirp, DIRENT_TYPE *entry, DIRENT_TYPE **result)
   DIRENT_TYPE *dp;
   size_t reclen;
   const int saved_errno = errno;
+  int ret;
 
   __libc_lock_lock (dirp->lock);
 
@@ -71,10 +71,10 @@ __READDIR_R (DIR *dirp, DIRENT_TYPE *entry, DIRENT_TYPE **result)
 		  bytes = 0;
 		  __set_errno (saved_errno);
 		}
+	      if (bytes < 0)
+		dirp->errcode = errno;
 
 	      dp = NULL;
-	      /* Reclen != 0 signals that an error occurred.  */
-	      reclen = bytes != 0;
 	      break;
 	    }
 	  dirp->size = (size_t) bytes;
@@ -107,29 +107,47 @@ __READDIR_R (DIR *dirp, DIRENT_TYPE *entry, DIRENT_TYPE **result)
       dirp->filepos += reclen;
 #endif
 
-      /* Skip deleted files.  */
+#ifdef NAME_MAX
+      if (reclen > offsetof (DIRENT_TYPE, d_name) + NAME_MAX + 1)
+	{
+	  /* The record is very long.  It could still fit into the
+	     caller-supplied buffer if we can skip padding at the
+	     end.  */
+	  size_t namelen = strlen(dp->d_name);
+	  if (namelen <= NAME_MAX)
+	    reclen = offsetof (DIRENT_TYPE, d_name) + namelen + 1;
+	  else
+	    {
+	      /* The name is too long.  Ignore this file.  */
+	      dirp->errcode = ENAMETOOLONG;
+	      dp->d_ino = 0;
+	      continue;
+	    }
+	}
+#endif
+
+      /* Skip deleted and ignored files.  */
     }
   while (dp->d_ino == 0);
 
   if (dp != NULL)
     {
-#ifdef GETDENTS_64BIT_ALIGNED
-      /* The d_reclen value might include padding which is not part of
-	 the DIRENT_TYPE data structure.  */
-      reclen = MIN (reclen,
-		    offsetof (DIRENT_TYPE, d_name) + sizeof (dp->d_name));
-#endif
       *result = memcpy (entry, dp, reclen);
-#ifdef GETDENTS_64BIT_ALIGNED
+#ifdef _DIRENT_HAVE_D_RECLEN
       entry->d_reclen = reclen;
 #endif
     }
   else
     *result = NULL;
 
+  if (dp != 0)
+    ret = 0;
+  else
+    ret = dirp->errcode;
+
   __libc_lock_unlock (dirp->lock);
 
-  return dp != NULL ? 0 : reclen ? errno : 0;
+  return ret;
 }
 
 #ifdef __READDIR_R_ALIAS
diff --git a/sysdeps/unix/sysv/linux/i386/readdir64_r.c b/sysdeps/unix/sysv/linux/i386/readdir64_r.c
index 8471f03..5256974 100644
--- a/sysdeps/unix/sysv/linux/i386/readdir64_r.c
+++ b/sysdeps/unix/sysv/linux/i386/readdir64_r.c
@@ -18,7 +18,6 @@
 #define __READDIR_R __readdir64_r
 #define __GETDENTS __getdents64
 #define DIRENT_TYPE struct dirent64
-#define GETDENTS_64BIT_ALIGNED 1
 
 #include <sysdeps/posix/readdir_r.c>
 
diff --git a/sysdeps/unix/sysv/linux/wordsize-64/readdir_r.c b/sysdeps/unix/sysv/linux/wordsize-64/readdir_r.c
index 5ed8e95..290f2c8 100644
--- a/sysdeps/unix/sysv/linux/wordsize-64/readdir_r.c
+++ b/sysdeps/unix/sysv/linux/wordsize-64/readdir_r.c
@@ -1,5 +1,4 @@
 #define readdir64_r __no_readdir64_r_decl
-#define GETDENTS_64BIT_ALIGNED 1
 #include <sysdeps/posix/readdir_r.c>
 #undef readdir64_r
 weak_alias (__readdir_r, readdir64_r)

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]