take security_mmap_file() outside of ->mmap_sem
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/security/security.c b/security/security.c
index d91c66d..3b11b3b 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
@@ -657,11 +660,35 @@
return security_ops->file_ioctl(file, cmd, arg);
}
-int security_mmap_file(struct file *file, unsigned long reqprot,
- unsigned long prot, unsigned long flags)
+int security_mmap_file(struct file *file, unsigned long prot,
+ unsigned long flags)
{
+ unsigned long reqprot = prot;
int ret;
-
+ /*
+ * Does the application expect PROT_READ to imply PROT_EXEC?
+ *
+ * (the exception is when the underlying filesystem is noexec
+ * mounted, in which case we dont add PROT_EXEC.)
+ */
+ if (!(reqprot & PROT_READ))
+ goto out;
+ if (!(current->personality & READ_IMPLIES_EXEC))
+ goto out;
+ if (!file) {
+ prot |= PROT_EXEC;
+ } else 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))
+ goto out;
+#endif
+ prot |= PROT_EXEC;
+ }
+out:
ret = security_ops->mmap_file(file, reqprot, prot, flags);
if (ret)
return ret;