Merge tag 'efi-urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into x86/urgent

Pull EFI fixes from Matt Fleming:

 * Prevent accidental deletion of EFI variables through efivarfs that
   may brick machines. We use a whitelist of known-safe variables to
   allow things like installing distributions to work out of the box, and
   instead restrict vendor-specific variable deletion by making
   non-whitelist variables immutable (Peter Jones)

Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 87 insertions, 4 deletions

diff --git a/tools/testing/selftests/efivarfs/efivarfs.sh b/tools/testing/selftests/efivarfs/efivarfs.sh
index 77edcdcc016b..057278448515 100755
--- a/tools/testing/selftests/efivarfs/efivarfs.sh
+++ b/tools/testing/selftests/efivarfs/efivarfs.sh
@@ -88,7 +88,11 @@ test_delete()
                 exit 1
         fi
 
-        rm $file
+        rm $file 2>/dev/null
+        if [ $? -ne 0 ]; then
+                chattr -i $file
+                rm $file
+        fi
 
         if [ -e $file ]; then
                 echo "$file couldn't be deleted" >&2
@@ -111,6 +115,7 @@ test_zero_size_delete()
                 exit 1
         fi
 
+        chattr -i $file
         printf "$attrs" > $file
 
         if [ -e $file ]; then
@@ -141,7 +146,11 @@ test_valid_filenames()
                         echo "$file could not be created" >&2
                         ret=1
                 else
-                        rm $file
+                        rm $file 2>/dev/null
+                        if [ $? -ne 0 ]; then
+                                chattr -i $file
+                                rm $file
+                        fi
                 fi
         done
 
@@ -174,7 +183,11 @@ test_invalid_filenames()
 
                 if [ -e $file ]; then
                         echo "Creating $file should have failed" >&2
-                        rm $file
+                        rm $file 2>/dev/null
+                        if [ $? -ne 0 ]; then
+                                chattr -i $file
+                                rm $file
+                        fi
                         ret=1
                 fi
         done
diff --git a/tools/testing/selftests/efivarfs/open-unlink.c b/tools/testing/selftests/efivarfs/open-unlink.c
index 8c0764407b3c..4af74f733036 100644
--- a/tools/testing/selftests/efivarfs/open-unlink.c
+++ b/tools/testing/selftests/efivarfs/open-unlink.c
@@ -1,10 +1,68 @@
+#include <errno.h>
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <sys/ioctl.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
+#include <linux/fs.h>
+
+static int set_immutable(const char *path, int immutable)
+{
+        unsigned int flags;
+        int fd;
+        int rc;
+        int error;
+
+        fd = open(path, O_RDONLY);
+        if (fd < 0)
+                return fd;
+
+        rc = ioctl(fd, FS_IOC_GETFLAGS, &flags);
+        if (rc < 0) {
+                error = errno;
+                close(fd);
+                errno = error;
+                return rc;
+        }
+
+        if (immutable)
+                flags |= FS_IMMUTABLE_FL;
+        else
+                flags &= ~FS_IMMUTABLE_FL;
+
+        rc = ioctl(fd, FS_IOC_SETFLAGS, &flags);
+        error = errno;
+        close(fd);
+        errno = error;
+        return rc;
+}
+
+static int get_immutable(const char *path)
+{
+        unsigned int flags;
+        int fd;
+        int rc;
+        int error;
+
+        fd = open(path, O_RDONLY);
+        if (fd < 0)
+                return fd;
+
+        rc = ioctl(fd, FS_IOC_GETFLAGS, &flags);
+        if (rc < 0) {
+                error = errno;
+                close(fd);
+                errno = error;
+                return rc;
+        }
+        close(fd);
+        if (flags & FS_IMMUTABLE_FL)
+                return 1;
+        return 0;
+}
 
 int main(int argc, char **argv)
 {
@@ -27,7 +85,7 @@ int main(int argc, char **argv)
         buf[4] = 0;
 
         /* create a test variable */
-        fd = open(path, O_WRONLY | O_CREAT);
+        fd = open(path, O_WRONLY | O_CREAT, 0600);
         if (fd < 0) {
                 perror("open(O_WRONLY)");
                 return EXIT_FAILURE;
@@ -41,6 +99,18 @@ int main(int argc, char **argv)
 
         close(fd);
 
+        rc = get_immutable(path);
+        if (rc < 0) {
+                perror("ioctl(FS_IOC_GETFLAGS)");
+                return EXIT_FAILURE;
+        } else if (rc) {
+                rc = set_immutable(path, 0);
+                if (rc < 0) {
+                        perror("ioctl(FS_IOC_SETFLAGS)");
+                        return EXIT_FAILURE;
+                }
+        }
+
         fd = open(path, O_RDONLY);
         if (fd < 0) {
                 perror("open");