From b451bfd224da44e93cf842f23455d755e48421dd Mon Sep 17 00:00:00 2001

From: Pavel Raiskup <praiskup@redhat.com>

Date: Mon, 28 Jul 2014 08:17:55 +0200

Subject: [PATCH 8/9] Fix for infinite loops during sparse file handling

Upstream bugreport (still downstream):

http://www.mail-archive.com/bug-tar@gnu.org/msg04432.html

Resolves: #1082608

---

 THANKS       |  1 +

 src/sparse.c | 48 ++++++++++++++++++++++++++++++++----------------

 2 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/THANKS b/THANKS

index b4c5427..e74f71c 100644

--- a/THANKS

+++ b/THANKS

@@ -175,6 +175,7 @@ Fabio d'Alessi		cars@civ.bio.unipd.it

 Frank Heckenbach	frank@g-n-u.de

 Frank Koenen		koenfr@lidp.com

 Franz-Werner Gergen	gergen@edvulx.mpi-stuttgart.mpg.de

+François Ouellet	fouell@gmail.com

 François Pinard		pinard@iro.umontreal.ca

 Fritz Elfert		fritz@fsun.triltsch.de

 George Chyu		gschyu@ccgate.dp.beckman.com

diff --git a/src/sparse.c b/src/sparse.c

index 6a97676..53c1868 100644

--- a/src/sparse.c

+++ b/src/sparse.c

@@ -301,6 +301,7 @@ sparse_dump_region (struct tar_sparse_file *file, size_t i)

 {

   union block *blk;

   off_t bytes_left = file->stat_info->sparse_map[i].numbytes;

+  const char *file_name = file->stat_info->orig_file_name;

   if (!lseek_or_error (file, file->stat_info->sparse_map[i].offset))

     return false;

@@ -314,13 +315,23 @@ sparse_dump_region (struct tar_sparse_file *file, size_t i)

       bytes_read = safe_read (file->fd, blk->buffer, bufsize);

       if (bytes_read == SAFE_READ_ERROR)

 	{

-          read_diag_details (file->stat_info->orig_file_name,

+          read_diag_details (file_name,

 	                     (file->stat_info->sparse_map[i].offset

 			      + file->stat_info->sparse_map[i].numbytes

 			      - bytes_left),

 			     bufsize);

 	  return false;

 	}

+      if (bytes_read == 0)

+        {

+          char buf[UINTMAX_STRSIZE_BOUND];

+          FATAL_ERROR ((0, 0,

+                        ngettext ("%s: File shrank by %s byte",

+                                  "%s: File shrank by %s bytes",

+                                  bytes_left),

+                        quotearg_colon (file_name),

+                        offtostr (bytes_left, buf)));

+        }

       memset (blk->buffer + bytes_read, 0, BLOCKSIZE - bytes_read);

       bytes_left -= bytes_read;

@@ -475,33 +486,37 @@ sparse_skip_file (struct tar_stat_info *st)

 static bool

 check_sparse_region (struct tar_sparse_file *file, off_t beg, off_t end)

 {

-  if (!lseek_or_error (file, beg))

+  off_t offset = beg;

+

+  if (!lseek_or_error (file, offset))

     return false;

-  while (beg < end)

+  while (offset < end)

     {

       size_t bytes_read;

-      size_t rdsize = BLOCKSIZE < end - beg ? BLOCKSIZE : end - beg;

+      size_t rdsize = BLOCKSIZE < end - offset ? BLOCKSIZE : end - offset;

       char diff_buffer[BLOCKSIZE];

       bytes_read = safe_read (file->fd, diff_buffer, rdsize);

       if (bytes_read == SAFE_READ_ERROR)

 	{

           read_diag_details (file->stat_info->orig_file_name,

-	                     beg,

-			     rdsize);

-	  return false;

-	}

-      if (!zero_block_p (diff_buffer, bytes_read))

-	{

-	  char begbuf[INT_BUFSIZE_BOUND (off_t)];

- 	  report_difference (file->stat_info,

-			     _("File fragment at %s is not a hole"),

-			     offtostr (beg, begbuf));

+	                     offset, rdsize);

 	  return false;

 	}

-      beg += bytes_read;

+      if (bytes_read == 0

+          || !zero_block_p (diff_buffer, bytes_read))

+        {

+          char begbuf[INT_BUFSIZE_BOUND (off_t)];

+          const char *msg = bytes_read ? _("File fragment at %s is not a hole")

+                                       : _("Hole starting at %s is truncated");

+

+          report_difference (file->stat_info, msg, offtostr (beg, begbuf));

+          return false;

+        }

+

+      offset += bytes_read;

     }

   return true;

 }

@@ -542,7 +557,8 @@ check_data_region (struct tar_sparse_file *file, size_t i)

       file->dumped_size += bytes_read;

       size_left -= bytes_read;

       mv_size_left (file->stat_info->archive_file_size - file->dumped_size);

-      if (memcmp (blk->buffer, diff_buffer, rdsize))

+      if (bytes_read == 0

+          || memcmp (blk->buffer, diff_buffer, bytes_read))

 	{

 	  report_difference (file->stat_info, _("Contents differ"));

 	  return false;

-- 

1.9.3