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>
git-mirror · Aug 22, 2006 · 00a2b0f · 00a2b0f
1 parent c164a9b
commit 00a2b0f
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Showing 2 changed files with 40 additions and 26 deletions.
diff --git 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
@@ -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);
 			}
 		}
 	}