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: Adrian Bunk <bunk@stusta.de>

diff --git a/fs/udf/super.c b/fs/udf/super.c
index 368d8f81fe54777c8c0f3a6e2e9d7aac2b912562..c5191e1d7fcfb85587445863d554f0baedb09725 100644 (file)
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -1657,7 +1657,7 @@ 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);
                        }
                }
        }