Commit 28bba2c2 authored by Ryan Roberts's avatar Ryan Roberts Committed by Andrew Morton
Browse files

fsnotify: pass correct offset to fsnotify_mmap_perm() 

fsnotify_mmap_perm() requires a byte offset for the file about to be
mmap'ed.  But it is called from vm_mmap_pgoff(), which has a page offset. 
Previously the conversion was done incorrectly so let's fix it, being
careful not to overflow on 32-bit platforms.

Discovered during code review.

Link: https://lkml.kernel.org/r/20251003155238.2147410-1-ryan.roberts@arm.com


Fixes: 066e053f ("fsnotify: add pre-content hooks on mmap()")
Signed-off-by: default avatarRyan Roberts <ryan.roberts@arm.com>
Reviewed-by: default avatarKiryl Shutsemau <kas@kernel.org>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent f04aad36

mm/util.c

+2 −1
Original line number Diff line number Diff line
@@ -566,6 +566,7 @@ unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr, 
	unsigned long len, unsigned long prot,

	unsigned long flag, unsigned long pgoff)

{

	loff_t off = (loff_t)pgoff << PAGE_SHIFT;

	unsigned long ret;

	struct mm_struct *mm = current->mm;

	unsigned long populate;
@@ -573,7 +574,7 @@ unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr, 


	ret = security_mmap_file(file, prot, flag);

	if (!ret)

		ret = fsnotify_mmap_perm(file, prot, pgoff >> PAGE_SHIFT, len);

		ret = fsnotify_mmap_perm(file, prot, off, len);

	if (!ret) {

		if (mmap_write_lock_killable(mm))

			return -EINTR;