From f81cff0d4067e41fd7383d9c013cc82da7c169d2 Mon Sep 17 00:00:00 2001 From: Mike Frysinger Date: Wed, 6 Dec 2006 12:02:59 +1000 Subject: [PATCH] [PATCH] uclinux: fix mmap() of directory for nommu case I was playing with blackfin when i hit a neat bug ... doing an open() on a directory and then passing that fd to mmap() would cause the kernel to hang after poking into the code a bit more, i found that mm/nommu.c:validate_mmap_request() checks the length and if it is 0, just returns the address ... this is in stark contrast to mmu's mm/mmap.c:do_mmap_pgoff() where it returns -EINVAL for 0 length requests ... i then noticed that some other parts of the logic is out of date between the two funcs, so perhaps that's the easy fix ? Signed-off-by: Greg Ungerer Signed-off-by: Linus Torvalds --- mm/nommu.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/mm/nommu.c b/mm/nommu.c index 8bdde9508f3..6a2a8aada40 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -497,15 +497,17 @@ static int validate_mmap_request(struct file *file, (flags & MAP_TYPE) != MAP_SHARED) return -EINVAL; - if (PAGE_ALIGN(len) == 0) - return addr; - - if (len > TASK_SIZE) + if (!len) return -EINVAL; + /* Careful about overflows.. */ + len = PAGE_ALIGN(len); + if (!len || len > TASK_SIZE) + return -ENOMEM; + /* offset overflow? */ if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) - return -EINVAL; + return -EOVERFLOW; if (file) { /* validate file mapping requests */ -- 2.41.1