1 files changed, 46 insertions, 5 deletions

diff --git a/security/security.c b/security/security.c
index 5497a57fba01..3efc9b12aef4 100644
--- a/security/security.c
+++ b/security/security.c
@@ -20,6 +20,9 @@
 #include <linux/ima.h>
 #include <linux/evm.h>
 #include <linux/fsnotify.h>
+#include <linux/mman.h>
+#include <linux/mount.h>
+#include <linux/personality.h>
 #include <net/flow.h>
 
 #define MAX_LSM_EVM_XATTR       2
@@ -657,18 +660,56 @@ int security_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
         return security_ops->file_ioctl(file, cmd, arg);
 }
 
-int security_file_mmap(struct file *file, unsigned long reqprot,
-                        unsigned long prot, unsigned long flags,
-                        unsigned long addr, unsigned long addr_only)
+static inline unsigned long mmap_prot(struct file *file, unsigned long prot)
 {
-        int ret;
+        /*
+         * Does we have PROT_READ and does the application expect
+         * it to imply PROT_EXEC?  If not, nothing to talk about...
+         */
+        if ((prot & (PROT_READ | PROT_EXEC)) != PROT_READ)
+                return prot;
+        if (!(current->personality & READ_IMPLIES_EXEC))
+                return prot;
+        /*
+         * if that's an anonymous mapping, let it.
+         */
+        if (!file)
+                return prot | PROT_EXEC;
+        /*
+         * ditto if it's not on noexec mount, except that on !MMU we need
+         * BDI_CAP_EXEC_MMAP (== VM_MAYEXEC) in this case
+         */
+        if (!(file->f_path.mnt->mnt_flags & MNT_NOEXEC)) {
+#ifndef CONFIG_MMU
+                unsigned long caps = 0;
+                struct address_space *mapping = file->f_mapping;
+                if (mapping && mapping->backing_dev_info)
+                        caps = mapping->backing_dev_info->capabilities;
+                if (!(caps & BDI_CAP_EXEC_MAP))
+                        return prot;
+#endif
+                return prot | PROT_EXEC;
+        }
+        /* anything on noexec mount won't get PROT_EXEC */
+        return prot;
+}
 
-        ret = security_ops->file_mmap(file, reqprot, prot, flags, addr, addr_only);
+int security_mmap_file(struct file *file, unsigned long prot,
+                        unsigned long flags)
+{
+        int ret;
+        ret = security_ops->mmap_file(file, prot,
+                                        mmap_prot(file, prot), flags);
         if (ret)
                 return ret;
         return ima_file_mmap(file, prot);
 }
 
+int security_mmap_addr(unsigned long addr)
+{
+        return security_ops->mmap_addr(addr);
+}
+
 int security_file_mprotect(struct vm_area_struct *vma, unsigned long reqprot,
                             unsigned long prot)
 {