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-rw-r--r--mm/nommu.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/nommu.c b/mm/nommu.c
index 28754c40be9..4bde489ec43 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) &&