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authorAl Viro <viro@zeniv.linux.org.uk>2012-05-30 19:58:30 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2012-06-01 10:37:17 -0400
commit98de59bfe4b2ff6344d9ad8e5296f80de5dcc5b6 (patch)
treef2baf4a8eec3299d5e55dd3899812407cd6d52a7 /security
parent9ac4ed4bd0adec75db13a4b08a39a3918ec0e3c9 (diff)
downloadlinux-98de59bfe4b2ff6344d9ad8e5296f80de5dcc5b6.tar.gz
take calculation of final prot in security_mmap_file() into a helper
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'security')
-rw-r--r--security/security.c46
1 files changed, 28 insertions, 18 deletions
diff --git a/security/security.c b/security/security.c
index 3b11b3b72fe..3efc9b12aef 100644
--- a/security/security.c
+++ b/security/security.c
@@ -660,36 +660,46 @@ int security_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
return security_ops->file_ioctl(file, cmd, arg);
}
-int security_mmap_file(struct file *file, unsigned long prot,
- unsigned long flags)
+static inline unsigned long mmap_prot(struct file *file, unsigned long prot)
{
- 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.)
+ * Does we have PROT_READ and does the application expect
+ * it to imply PROT_EXEC? If not, nothing to talk about...
*/
- if (!(reqprot & PROT_READ))
- goto out;
+ if ((prot & (PROT_READ | PROT_EXEC)) != PROT_READ)
+ return prot;
if (!(current->personality & READ_IMPLIES_EXEC))
- goto out;
- if (!file) {
- prot |= PROT_EXEC;
- } else if (!(file->f_path.mnt->mnt_flags & MNT_NOEXEC)) {
+ 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))
- goto out;
+ return prot;
#endif
- prot |= PROT_EXEC;
+ return prot | PROT_EXEC;
}
-out:
- ret = security_ops->mmap_file(file, reqprot, prot, flags);
+ /* anything on noexec mount won't get PROT_EXEC */
+ return prot;
+}
+
+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);