diff options
| -rw-r--r-- | Documentation/prctl/no_new_privs.txt | 7 | ||||
| -rw-r--r-- | Makefile | 2 | ||||
| -rw-r--r-- | fs/open.c | 6 | ||||
| -rw-r--r-- | include/linux/prctl.h | 2 |
4 files changed, 13 insertions, 4 deletions
diff --git a/Documentation/prctl/no_new_privs.txt b/Documentation/prctl/no_new_privs.txt index cb705ec69abe..f7be84fba910 100644 --- a/Documentation/prctl/no_new_privs.txt +++ b/Documentation/prctl/no_new_privs.txt @@ -25,6 +25,13 @@ bits will no longer change the uid or gid; file capabilities will not add to the permitted set, and LSMs will not relax constraints after execve. +To set no_new_privs, use prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0). + +Be careful, though: LSMs might also not tighten constraints on exec +in no_new_privs mode. (This means that setting up a general-purpose +service launcher to set no_new_privs before execing daemons may +interfere with LSM-based sandboxing.) + Note that no_new_privs does not prevent privilege changes that do not involve execve. An appropriately privileged task can still call setuid(2) and receive SCM_RIGHTS datagrams. @@ -1,7 +1,7 @@ VERSION = 3 PATCHLEVEL = 5 SUBLEVEL = 0 -EXTRAVERSION = -rc5 +EXTRAVERSION = -rc6 NAME = Saber-toothed Squirrel # *DOCUMENTATION* diff --git a/fs/open.c b/fs/open.c index d6c79a0dffc7..1540632d8387 100644 --- a/fs/open.c +++ b/fs/open.c @@ -397,10 +397,10 @@ SYSCALL_DEFINE1(fchdir, unsigned int, fd) { struct file *file; struct inode *inode; - int error; + int error, fput_needed; error = -EBADF; - file = fget(fd); + file = fget_raw_light(fd, &fput_needed); if (!file) goto out; @@ -414,7 +414,7 @@ SYSCALL_DEFINE1(fchdir, unsigned int, fd) if (!error) set_fs_pwd(current->fs, &file->f_path); out_putf: - fput(file); + fput_light(file, fput_needed); out: return error; } diff --git a/include/linux/prctl.h b/include/linux/prctl.h index 3988012255dc..289760f424aa 100644 --- a/include/linux/prctl.h +++ b/include/linux/prctl.h @@ -141,6 +141,8 @@ * Changing LSM security domain is considered a new privilege. So, for example, * asking selinux for a specific new context (e.g. with runcon) will result * in execve returning -EPERM. + * + * See Documentation/prctl/no_new_privs.txt for more details. */ #define PR_SET_NO_NEW_PRIVS 38 #define PR_GET_NO_NEW_PRIVS 39 |