Fix possible UDF deadlock and memory corruption (CVE-2006-4145)

UDF code is not really ready to handle extents larger that 1GB. This is
the easy way to forbid creating those.

Also truncation code did not count with the case when there are no
extents in the file and we are extending the file.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/udf/super.c b/fs/udf/super.c
index 7de172efa0841eac8239b72b839138e0adab4146..fcce1a21a51bdc1c0a095ccc815d35bd6399bf0f 100644 (file)
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -1659,7 +1659,7 @@ static int udf_fill_super(struct super_block *sb, void *options, int silent)
                iput(inode);
                goto error_out;
        }
-       sb->s_maxbytes = MAX_LFS_FILESIZE;
+       sb->s_maxbytes = 1<<30;
        return 0;
 
 error_out:

diff --git a/fs/udf/truncate.c b/fs/udf/truncate.c
index e1b0e8cfecb4947a120c2c5eeb78848b7604fa32..0abd66ce36ea042091bd6564ff17b003257a2d24 100644 (file)
--- a/fs/udf/truncate.c
+++ b/fs/udf/truncate.c
@@ -239,37 +239,51 @@ void udf_truncate_extents(struct inode * inode)
        {
                if (offset)
                {
-                       extoffset -= adsize;
-                       etype = udf_next_aext(inode, &bloc, &extoffset, &eloc, &elen, &bh, 1);
-                       if (etype == (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
-                       {
-                               extoffset -= adsize;
-                               elen = EXT_NOT_RECORDED_NOT_ALLOCATED | (elen + offset);
-                               udf_write_aext(inode, bloc, &extoffset, eloc, elen, bh, 0);
+                       /*
+                        *  OK, there is not extent covering inode->i_size and
+                        *  no extent above inode->i_size => truncate is
+                        *  extending the file by 'offset'.
+                        */
+                       if ((!bh && extoffset == udf_file_entry_alloc_offset(inode)) ||
+                           (bh && extoffset == sizeof(struct allocExtDesc))) {
+                               /* File has no extents at all! */
+                               memset(&eloc, 0x00, sizeof(kernel_lb_addr));
+                               elen = EXT_NOT_RECORDED_NOT_ALLOCATED | offset;
+                               udf_add_aext(inode, &bloc, &extoffset, eloc, elen, &bh, 1);
                        }
-                       else if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30))
-                       {
-                               kernel_lb_addr neloc = { 0, 0 };
+                       else {
                                extoffset -= adsize;
-                               nelen = EXT_NOT_RECORDED_NOT_ALLOCATED |
-                                       ((elen + offset + inode->i_sb->s_blocksize - 1) &
-                                       ~(inode->i_sb->s_blocksize - 1));
-                               udf_write_aext(inode, bloc, &extoffset, neloc, nelen, bh, 1);
-                               udf_add_aext(inode, &bloc, &extoffset, eloc, (etype << 30) | elen, &bh, 1);
-                       }
-                       else
-                       {
-                               if (elen & (inode->i_sb->s_blocksize - 1))
+                               etype = udf_next_aext(inode, &bloc, &extoffset, &eloc, &elen, &bh, 1);
+                               if (etype == (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
+                               {
+                                       extoffset -= adsize;
+                                       elen = EXT_NOT_RECORDED_NOT_ALLOCATED | (elen + offset);
+                                       udf_write_aext(inode, bloc, &extoffset, eloc, elen, bh, 0);
+                               }
+                               else if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30))
                                {
+                                       kernel_lb_addr neloc = { 0, 0 };
                                        extoffset -= adsize;
-                                       elen = EXT_RECORDED_ALLOCATED |
-                                               ((elen + inode->i_sb->s_blocksize - 1) &
+                                       nelen = EXT_NOT_RECORDED_NOT_ALLOCATED |
+                                               ((elen + offset + inode->i_sb->s_blocksize - 1) &
                                                ~(inode->i_sb->s_blocksize - 1));
-                                       udf_write_aext(inode, bloc, &extoffset, eloc, elen, bh, 1);
+                                       udf_write_aext(inode, bloc, &extoffset, neloc, nelen, bh, 1);
+                                       udf_add_aext(inode, &bloc, &extoffset, eloc, (etype << 30) | elen, &bh, 1);
+                               }
+                               else
+                               {
+                                       if (elen & (inode->i_sb->s_blocksize - 1))
+                                       {
+                                               extoffset -= adsize;
+                                               elen = EXT_RECORDED_ALLOCATED |
+                                                       ((elen + inode->i_sb->s_blocksize - 1) &
+                                                       ~(inode->i_sb->s_blocksize - 1));
+                                               udf_write_aext(inode, bloc, &extoffset, eloc, elen, bh, 1);
+                                       }
+                                       memset(&eloc, 0x00, sizeof(kernel_lb_addr));
+                                       elen = EXT_NOT_RECORDED_NOT_ALLOCATED | offset;
+                                       udf_add_aext(inode, &bloc, &extoffset, eloc, elen, &bh, 1);
                                }
-                               memset(&eloc, 0x00, sizeof(kernel_lb_addr));
-                               elen = EXT_NOT_RECORDED_NOT_ALLOCATED | offset;
-                               udf_add_aext(inode, &bloc, &extoffset, eloc, elen, &bh, 1);
                        }
                }
        }