X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=fs%2Fromfs%2Fmmap-nommu.c;h=eed99428f1046d6a3dbd6191340d9d70e18b7ce0;hb=c8618d16f91f58c01be4bdbec4d724efe426a081;hp=f0511e8169679fa3872938a2a9e0e9c19998049b;hpb=cd208bcc7cb0acd851e25c951ec2a9c14b084eab;p=pandora-kernel.git

diff --git a/fs/romfs/mmap-nommu.c b/fs/romfs/mmap-nommu.c
index f0511e816967..eed99428f104 100644
--- a/fs/romfs/mmap-nommu.c
+++ b/fs/romfs/mmap-nommu.c
@@ -27,14 +27,18 @@ static unsigned long romfs_get_unmapped_area(struct file *file,
 {
 	struct inode *inode = file->f_mapping->host;
 	struct mtd_info *mtd = inode->i_sb->s_mtd;
-	unsigned long isize, offset;
+	unsigned long isize, offset, maxpages, lpages;
 
 	if (!mtd)
 		goto cant_map_directly;
 
+	/* the mapping mustn't extend beyond the EOF */
+	lpages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	isize = i_size_read(inode);
 	offset = pgoff << PAGE_SHIFT;
-	if (offset > isize || len > isize || offset > isize - len)
+
+	maxpages = (isize + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	if ((pgoff >= maxpages) || (maxpages - pgoff < lpages))
 		return (unsigned long) -EINVAL;
 
 	/* we need to call down to the MTD layer to do the actual mapping */