Messages in this thread Patch in this message | | | From | David Howells <> | Subject | [PATCH] NOMMU: Check fd read permission in validate_mmap_request() | Date | Fri, 14 Aug 2009 12:29:32 +0100 |
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From: Graff Yang <graff.yang@gmail.com>
According to the POSIX (1003.1-2008), the file descriptor shall have been opened with read permission, regardless of the protection options specified to mmap(). The ltp test cases mmap06/07 need this.
Signed-off-by: Graff Yang <graff.yang@gmail.com> Acked-by: Paul Mundt <lethal@linux-sh.org> Signed-off-by: David Howells <dhowells@redhat.com> ---
mm/nommu.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/mm/nommu.c b/mm/nommu.c index 1b2b59b..fd1e2b5 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -919,6 +919,10 @@ static int validate_mmap_request(struct file *file, if (!file->f_op->read) capabilities &= ~BDI_CAP_MAP_COPY; + /* The file shall have been opened with read permission. */ + if (!(file->f_mode & FMODE_READ)) + return -EACCES; + if (flags & MAP_SHARED) { /* do checks for writing, appending and locking */ if ((prot & PROT_WRITE) &&
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