named + capset = EPERM [Was: 2.6.24-rc3-mm2]

[Jiri Slaby <jirislaby@gmail.com>]

On 11/28/2007 12:41 PM, Andrew Morton wrote:
> ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.24-rc3/2.6.24-rc3-mm2/
[...]
> +capabilities-introduce-per-process-capability-bounding-set.patch

A regression against -mm1. This patch breaks bind (9.5.0-18.a7.fc8):
capset(0x19980330, 0,
{CAP_DAC_READ_SEARCH|CAP_SETGID|CAP_SETUID|CAP_NET_BIND_SERVICE|CAP_SYS_CHROOT|CAP_SYS_RESOURCE,
CAP_DAC_READ_SEARCH|CAP_SETGID|CAP_SETUID|CAP_NET_BIND_SERVICE|CAP_SYS_CHROOT|CAP_SYS_RESOURCE,
0}) = -1 EPERM (Operation not permitted)

$ grep SEC .config
CONFIG_SECCOMP=y
# CONFIG_NETWORK_SECMARK is not set
CONFIG_RPCSEC_GSS_KRB5=m
# CONFIG_RPCSEC_GSS_SPKM3 is not set
# CONFIG_SECURITY is not set
# CONFIG_SECURITY_FILE_CAPABILITIES is not set

probably this hunk?:
@@ -133,6 +119,12 @@ int cap_capset_check (struct task_struct
                /* incapable of using this inheritable set */
                return -EPERM;
        }
+       if (!!cap_issubset(*inheritable,
+                          cap_combine(target->cap_inheritable,
+                                      current->cap_bset))) {
+               /* no new pI capabilities outside bounding set */
+               return -EPERM;
+       }

        /* verify restrictions on target's new Permitted set */
        if (!cap_issubset (*permitted,


regards,
-- 
Jiri Slaby (jirislaby@gmail.com)
Faculty of Informatics, Masaryk University