diff options
Diffstat (limited to 'security/commoncap.c')
| -rw-r--r-- | security/commoncap.c | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/security/commoncap.c b/security/commoncap.c index beac0258c2a..e3097c0a131 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -28,6 +28,28 @@ #include <linux/prctl.h> #include <linux/securebits.h> +/* + * If a non-root user executes a setuid-root binary in + * !secure(SECURE_NOROOT) mode, then we raise capabilities. + * However if fE is also set, then the intent is for only + * the file capabilities to be applied, and the setuid-root + * bit is left on either to change the uid (plausible) or + * to get full privilege on a kernel without file capabilities + * support. So in that case we do not raise capabilities. + * + * Warn if that happens, once per boot. + */ +static void warn_setuid_and_fcaps_mixed(char *fname) +{ + static int warned; + if (!warned) { + printk(KERN_INFO "warning: `%s' has both setuid-root and" + " effective capabilities. Therefore not raising all" + " capabilities.\n", fname); + warned = 1; + } +} + int cap_netlink_send(struct sock *sk, struct sk_buff *skb) { NETLINK_CB(skb).eff_cap = current_cap(); @@ -464,6 +486,15 @@ int cap_bprm_set_creds(struct linux_binprm *bprm) if (!issecure(SECURE_NOROOT)) { /* + * If the legacy file capability is set, then don't set privs + * for a setuid root binary run by a non-root user. Do set it + * for a root user just to cause least surprise to an admin. + */ + if (effective && new->uid != 0 && new->euid == 0) { + warn_setuid_and_fcaps_mixed(bprm->filename); + goto skip; + } + /* * To support inheritance of root-permissions and suid-root * executables under compatibility mode, we override the * capability sets for the file. @@ -478,6 +509,7 @@ int cap_bprm_set_creds(struct linux_binprm *bprm) if (new->euid == 0) effective = true; } +skip: /* Don't let someone trace a set[ug]id/setpcap binary with the revised * credentials unless they have the appropriate permit @@ -952,3 +984,33 @@ int cap_vm_enough_memory(struct mm_struct *mm, long pages) cap_sys_admin = 1; return __vm_enough_memory(mm, pages, cap_sys_admin); } + +/* + * cap_file_mmap - check if able to map given addr + * @file: unused + * @reqprot: unused + * @prot: unused + * @flags: unused + * @addr: address attempting to be mapped + * @addr_only: unused + * + * If the process is attempting to map memory below mmap_min_addr they need + * CAP_SYS_RAWIO. The other parameters to this function are unused by the + * capability security module. Returns 0 if this mapping should be allowed + * -EPERM if not. + */ +int cap_file_mmap(struct file *file, unsigned long reqprot, + unsigned long prot, unsigned long flags, + unsigned long addr, unsigned long addr_only) +{ + int ret = 0; + + if (addr < dac_mmap_min_addr) { + ret = cap_capable(current, current_cred(), CAP_SYS_RAWIO, + SECURITY_CAP_AUDIT); + /* set PF_SUPERPRIV if it turns out we allow the low mmap */ + if (ret == 0) + current->flags |= PF_SUPERPRIV; + } + return ret; +} |