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-rw-r--r--fs/open.c37
1 files changed, 22 insertions, 15 deletions
diff --git a/fs/open.c b/fs/open.c
index a145008..a99ad09 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -16,6 +16,7 @@
#include <linux/namei.h>
#include <linux/backing-dev.h>
#include <linux/capability.h>
+#include <linux/securebits.h>
#include <linux/security.h>
#include <linux/mount.h>
#include <linux/vfs.h>
@@ -425,7 +426,7 @@ asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode)
{
struct nameidata nd;
int old_fsuid, old_fsgid;
- kernel_cap_t old_cap;
+ kernel_cap_t uninitialized_var(old_cap); /* !SECURE_NO_SETUID_FIXUP */
int res;
if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
@@ -433,23 +434,27 @@ asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode)
old_fsuid = current->fsuid;
old_fsgid = current->fsgid;
- old_cap = current->cap_effective;
current->fsuid = current->uid;
current->fsgid = current->gid;
- /*
- * Clear the capabilities if we switch to a non-root user
- *
- * FIXME: There is a race here against sys_capset. The
- * capabilities can change yet we will restore the old
- * value below. We should hold task_capabilities_lock,
- * but we cannot because user_path_walk can sleep.
- */
- if (current->uid)
- cap_clear(current->cap_effective);
- else
- current->cap_effective = current->cap_permitted;
+ if (!issecure(SECURE_NO_SETUID_FIXUP)) {
+ /*
+ * Clear the capabilities if we switch to a non-root user
+ */
+#ifndef CONFIG_SECURITY_FILE_CAPABILITIES
+ /*
+ * FIXME: There is a race here against sys_capset. The
+ * capabilities can change yet we will restore the old
+ * value below. We should hold task_capabilities_lock,
+ * but we cannot because user_path_walk can sleep.
+ */
+#endif /* ndef CONFIG_SECURITY_FILE_CAPABILITIES */
+ if (current->uid)
+ old_cap = cap_set_effective(__cap_empty_set);
+ else
+ old_cap = cap_set_effective(current->cap_permitted);
+ }
res = __user_walk_fd(dfd, filename, LOOKUP_FOLLOW|LOOKUP_ACCESS, &nd);
if (res)
@@ -478,7 +483,9 @@ out_path_release:
out:
current->fsuid = old_fsuid;
current->fsgid = old_fsgid;
- current->cap_effective = old_cap;
+
+ if (!issecure(SECURE_NO_SETUID_FIXUP))
+ cap_set_effective(old_cap);
return res;
}