From e4ba4fc2b98f659f525d02721643a01015a8e3ed Mon Sep 17 00:00:00 2001 From: Greg Ungerer Date: Tue, 2 Apr 2013 14:25:33 +1000 Subject: romfs: fix nommu map length to keep inside filesystem Checks introduced in commit 4991e7251 ("romfs: do not use mtd->get_unmapped_area directly") re-introduce problems fixed in the earlier commit 2b4b2482e ("romfs: fix romfs_get_unmapped_area() argument check"). If a flat binary app is located at the end of a romfs, its page aligned length may be outside of the romfs filesystem. The flat binary loader, via nommu do_mmap_pgoff(), page aligns the length it is mmaping. So simple offset+size checks will fail - returning EINVAL. We can truncate the length to keep it inside the romfs filesystem, and that also keeps the call to mtd_get_unmapped_area() happy. Are there any side effects to truncating the size here though? Signed-off-by: Greg Ungerer --- fs/romfs/mmap-nommu.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/romfs/mmap-nommu.c b/fs/romfs/mmap-nommu.c index e1a7779dd3cb..f373bde8f545 100644 --- a/fs/romfs/mmap-nommu.c +++ b/fs/romfs/mmap-nommu.c @@ -49,8 +49,11 @@ static unsigned long romfs_get_unmapped_area(struct file *file, return (unsigned long) -EINVAL; offset += ROMFS_I(inode)->i_dataoffset; - if (offset > mtd->size - len) + if (offset >= mtd->size) return (unsigned long) -EINVAL; + /* the mapping mustn't extend beyond the EOF */ + if ((offset + len) > mtd->size) + len = mtd->size - offset; ret = mtd_get_unmapped_area(mtd, len, offset, flags); if (ret == -EOPNOTSUPP) -- cgit v1.2.3