diff options
Diffstat (limited to '')
| -rw-r--r-- | debian/patches/debian/add-sysctl-to-disallow-unprivileged-CLONE_NEWUSER-by-default.patch | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/debian/patches/debian/add-sysctl-to-disallow-unprivileged-CLONE_NEWUSER-by-default.patch b/debian/patches/debian/add-sysctl-to-disallow-unprivileged-CLONE_NEWUSER-by-default.patch new file mode 100644 index 000000000..801fd6a8d --- /dev/null +++ b/debian/patches/debian/add-sysctl-to-disallow-unprivileged-CLONE_NEWUSER-by-default.patch @@ -0,0 +1,104 @@ +From: Serge Hallyn <serge.hallyn@canonical.com> +Date: Fri, 31 May 2013 19:12:12 +0000 (+0100) +Subject: add sysctl to disallow unprivileged CLONE_NEWUSER by default +Origin: http://kernel.ubuntu.com/git?p=serge%2Fubuntu-saucy.git;a=commit;h=5c847404dcb2e3195ad0057877e1422ae90892b8 + +add sysctl to disallow unprivileged CLONE_NEWUSER by default + +This is a short-term patch. Unprivileged use of CLONE_NEWUSER +is certainly an intended feature of user namespaces. However +for at least saucy we want to make sure that, if any security +issues are found, we have a fail-safe. + +Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com> +[bwh: Remove unneeded binary sysctl bits] +[bwh: Keep this sysctl, but change the default to enabled] +--- +diff --git a/kernel/fork.c b/kernel/fork.c +index efc5493203ae..bc596683cc31 100644 +--- a/kernel/fork.c ++++ b/kernel/fork.c +@@ -106,6 +106,11 @@ + + #define CREATE_TRACE_POINTS + #include <trace/events/task.h> ++#ifdef CONFIG_USER_NS ++extern int unprivileged_userns_clone; ++#else ++#define unprivileged_userns_clone 0 ++#endif + + /* + * Minimum number of threads to boot the kernel +@@ -1861,6 +1866,10 @@ static __latent_entropy struct task_struct *copy_process( + if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS)) + return ERR_PTR(-EINVAL); + ++ if ((clone_flags & CLONE_NEWUSER) && !unprivileged_userns_clone) ++ if (!capable(CAP_SYS_ADMIN)) ++ return ERR_PTR(-EPERM); ++ + /* + * Thread groups must share signals as well, and detached threads + * can only be started up within the thread group. +@@ -2961,6 +2970,12 @@ int ksys_unshare(unsigned long unshare_flags) + if (unshare_flags & CLONE_NEWNS) + unshare_flags |= CLONE_FS; + ++ if ((unshare_flags & CLONE_NEWUSER) && !unprivileged_userns_clone) { ++ err = -EPERM; ++ if (!capable(CAP_SYS_ADMIN)) ++ goto bad_unshare_out; ++ } ++ + err = check_unshare_flags(unshare_flags); + if (err) + goto bad_unshare_out; +diff --git a/kernel/sysctl.c b/kernel/sysctl.c +index db1ce7af2563..2bb29f495b02 100644 +--- a/kernel/sysctl.c ++++ b/kernel/sysctl.c +@@ -200,6 +200,10 @@ static int min_extfrag_threshold; + static int max_extfrag_threshold = 1000; + #endif + ++#ifdef CONFIG_USER_NS ++extern int unprivileged_userns_clone; ++#endif ++ + #endif /* CONFIG_SYSCTL */ + + #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_SYSCTL) +@@ -1882,6 +1886,15 @@ static struct ctl_table kern_table[] = { + .proc_handler = proc_dointvec, + }, + #endif ++#ifdef CONFIG_USER_NS ++ { ++ .procname = "unprivileged_userns_clone", ++ .data = &unprivileged_userns_clone, ++ .maxlen = sizeof(int), ++ .mode = 0644, ++ .proc_handler = proc_dointvec, ++ }, ++#endif + #ifdef CONFIG_PROC_SYSCTL + { + .procname = "tainted", +diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c +index 87804e0371fe..2fd16493231b 100644 +--- a/kernel/user_namespace.c ++++ b/kernel/user_namespace.c +@@ -21,6 +21,9 @@ + #include <linux/bsearch.h> + #include <linux/sort.h> + ++/* sysctl */ ++int unprivileged_userns_clone = 1; ++ + static struct kmem_cache *user_ns_cachep __read_mostly; + static DEFINE_MUTEX(userns_state_mutex); + +-- +2.27.0 + |