diff options
Diffstat (limited to 'userns-Check-euid-no-fsuid-when-establishing-an-unpr.patch')
| -rw-r--r-- | userns-Check-euid-no-fsuid-when-establishing-an-unpr.patch | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/userns-Check-euid-no-fsuid-when-establishing-an-unpr.patch b/userns-Check-euid-no-fsuid-when-establishing-an-unpr.patch new file mode 100644 index 000000000..50830c30e --- /dev/null +++ b/userns-Check-euid-no-fsuid-when-establishing-an-unpr.patch @@ -0,0 +1,39 @@ +From: "Eric W. Biederman" <ebiederm@xmission.com> +Date: Fri, 5 Dec 2014 18:26:30 -0600 +Subject: [PATCH] userns: Check euid no fsuid when establishing an unprivileged + uid mapping + +setresuid allows the euid to be set to any of uid, euid, suid, and +fsuid. Therefor it is safe to allow an unprivileged user to map +their euid and use CAP_SETUID privileged with exactly that uid, +as no new credentials can be obtained. + +I can not find a combination of existing system calls that allows setting +uid, euid, suid, and fsuid from the fsuid making the previous use +of fsuid for allowing unprivileged mappings a bug. + +This is part of a fix for CVE-2014-8989. + +Cc: stable@vger.kernel.org +Reviewed-by: Andy Lutomirski <luto@amacapital.net> +Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> +--- + kernel/user_namespace.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c +index 1ce6d67c07b7..9451b12a9b6c 100644 +--- a/kernel/user_namespace.c ++++ b/kernel/user_namespace.c +@@ -819,7 +819,7 @@ static bool new_idmap_permitted(const struct file *file, + u32 id = new_map->extent[0].lower_first; + if (cap_setid == CAP_SETUID) { + kuid_t uid = make_kuid(ns->parent, id); +- if (uid_eq(uid, file->f_cred->fsuid)) ++ if (uid_eq(uid, file->f_cred->euid)) + return true; + } + } +-- +2.1.0 + |