X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/d9a64523371fa019c4575bb400cbbc3a50ac9903..e8c3f78193f1895ea514044358b93b1add9322f3:/bsd/kern/posix_shm.c?ds=sidebyside

diff --git a/bsd/kern/posix_shm.c b/bsd/kern/posix_shm.c
index 1fe787812..d220614db 100644
--- a/bsd/kern/posix_shm.c
+++ b/bsd/kern/posix_shm.c
@@ -865,6 +865,7 @@ pshm_mmap(__unused proc_t p, struct mmap_args *uap, user_addr_t *retval, struct
 	vm_map_offset_t	user_start_addr;
 	vm_map_size_t	map_size, mapped_size;
 	int prot = uap->prot;
+	int max_prot = VM_PROT_DEFAULT;
 	int flags = uap->flags;
 	vm_object_offset_t file_pos = (vm_object_offset_t)uap->pos;
 	vm_object_offset_t map_pos;
@@ -887,8 +888,12 @@ pshm_mmap(__unused proc_t p, struct mmap_args *uap, user_addr_t *retval, struct
 		return(EINVAL);
 
 
-	if ((prot & PROT_WRITE) && ((fp->f_flag & FWRITE) == 0)) {
-		return(EPERM);
+	/* Can't allow write permission if the shm_open() didn't */
+	if (!(fp->f_flag & FWRITE)) {
+		if (prot & VM_PROT_WRITE) {
+			return EPERM;
+		}
+		max_prot &= ~VM_PROT_WRITE;
 	}
 
 	if (((pnode = (struct pshmnode *)fp->f_data)) == PSHMNODE_NULL )
@@ -1000,7 +1005,7 @@ pshm_mmap(__unused proc_t p, struct mmap_args *uap, user_addr_t *retval, struct
 			file_pos - map_pos,
 			docow,
 			prot,
-			VM_PROT_DEFAULT, 
+			max_prot,
 			VM_INHERIT_SHARE);
 		if (kret != KERN_SUCCESS) 
 			goto out;