grsecurity forums

Hello guys,

I have been using grsecurity + pax for a long time and have got some really weird problems now and don't know how to go on.

I compiled a kernel (with grsec enabled) and put this in a live system (which is only for installation of the real system).
Everything works really well. And the end of the installation there is a initramfs created with several storage drivers and what we need.

When I finally reboot the system mount gets killed by grsec (with signal 11 - segmentation fault) when mounting /proc, althought /proc gets mounted correctly, and all other pseudo-filesystem (/sys, /dev, /dev/pts), too.

Now, I don't know why mount succeedes in the live-system but crashes after the next reboot. I also don't know which component of grsec kills mount.
I already disabled PAE which lead to problems (read this in the forum).

How can I do more debugging?

Thanks in advance

Michael

My software:
Kernel 2.6.27.10 with grsecurity-2.1.12-2.6.27.10-200812271347.patch
mount is from util-linux-ng-2.14.1

Error message:

Code: Select all

grsec: signal 11 sent to /bin/mount[mount:14] uid/euid:0/0 gid/egid:0/0, parent /init[init:1] uid/euid:0/0 gid/egid:0/0

Excerpt of kernel config:

Code: Select all

#
# Security options
#

#
# Grsecurity
#
CONFIG_GRKERNSEC=y
# CONFIG_GRKERNSEC_LOW is not set
# CONFIG_GRKERNSEC_MEDIUM is not set
CONFIG_GRKERNSEC_HIGH=y
# CONFIG_GRKERNSEC_CUSTOM is not set

#
# Address Space Protection
#
CONFIG_GRKERNSEC_KMEM=y
# CONFIG_GRKERNSEC_IO is not set
CONFIG_GRKERNSEC_PROC_MEMMAP=y
CONFIG_GRKERNSEC_BRUTE=y
CONFIG_GRKERNSEC_MODSTOP=y
CONFIG_GRKERNSEC_HIDESYM=y

#
# Role Based Access Control Options
#
# CONFIG_GRKERNSEC_ACL_HIDEKERN is not set
CONFIG_GRKERNSEC_ACL_MAXTRIES=3
CONFIG_GRKERNSEC_ACL_TIMEOUT=30

#
# Filesystem Protections
#
CONFIG_GRKERNSEC_PROC=y
# CONFIG_GRKERNSEC_PROC_USER is not set
CONFIG_GRKERNSEC_PROC_USERGROUP=y
CONFIG_GRKERNSEC_PROC_GID=1001
CONFIG_GRKERNSEC_PROC_ADD=y
CONFIG_GRKERNSEC_LINK=y
CONFIG_GRKERNSEC_FIFO=y
CONFIG_GRKERNSEC_CHROOT=y
CONFIG_GRKERNSEC_CHROOT_MOUNT=y
CONFIG_GRKERNSEC_CHROOT_DOUBLE=y
CONFIG_GRKERNSEC_CHROOT_PIVOT=y
CONFIG_GRKERNSEC_CHROOT_CHDIR=y
CONFIG_GRKERNSEC_CHROOT_CHMOD=y
CONFIG_GRKERNSEC_CHROOT_FCHDIR=y
CONFIG_GRKERNSEC_CHROOT_MKNOD=y
CONFIG_GRKERNSEC_CHROOT_SHMAT=y
CONFIG_GRKERNSEC_CHROOT_UNIX=y
CONFIG_GRKERNSEC_CHROOT_FINDTASK=y
CONFIG_GRKERNSEC_CHROOT_NICE=y
CONFIG_GRKERNSEC_CHROOT_SYSCTL=y
CONFIG_GRKERNSEC_CHROOT_CAPS=y

#
# Kernel Auditing
#
# CONFIG_GRKERNSEC_AUDIT_GROUP is not set
# CONFIG_GRKERNSEC_EXECLOG is not set
CONFIG_GRKERNSEC_RESLOG=y
# CONFIG_GRKERNSEC_CHROOT_EXECLOG is not set
# CONFIG_GRKERNSEC_AUDIT_CHDIR is not set
CONFIG_GRKERNSEC_AUDIT_MOUNT=y
# CONFIG_GRKERNSEC_AUDIT_IPC is not set
CONFIG_GRKERNSEC_SIGNAL=y
CONFIG_GRKERNSEC_FORKFAIL=y
CONFIG_GRKERNSEC_TIME=y
CONFIG_GRKERNSEC_PROC_IPADDR=y
# CONFIG_GRKERNSEC_AUDIT_TEXTREL is not set

#
# Executable Protections
#
CONFIG_GRKERNSEC_EXECVE=y
CONFIG_GRKERNSEC_DMESG=y
# CONFIG_GRKERNSEC_TPE is not set

#
# Network Protections
#
CONFIG_GRKERNSEC_RANDNET=y
# CONFIG_GRKERNSEC_SOCKET is not set

#
# Sysctl support
#
CONFIG_GRKERNSEC_SYSCTL=y
CONFIG_GRKERNSEC_SYSCTL_ON=y

#
# Logging Options
#
CONFIG_GRKERNSEC_FLOODTIME=10
CONFIG_GRKERNSEC_FLOODBURST=4

#
# PaX
#
CONFIG_PAX=y

#
# PaX Control
#
# CONFIG_PAX_SOFTMODE is not set
CONFIG_PAX_EI_PAX=y
CONFIG_PAX_PT_PAX_FLAGS=y
# CONFIG_PAX_NO_ACL_FLAGS is not set
CONFIG_PAX_HAVE_ACL_FLAGS=y
# CONFIG_PAX_HOOK_ACL_FLAGS is not set

#
# Non-executable pages
#
CONFIG_PAX_NOEXEC=y
CONFIG_PAX_PAGEEXEC=y
CONFIG_PAX_SEGMEXEC=y
# CONFIG_PAX_EMUTRAMP is not set
CONFIG_PAX_MPROTECT=y
# CONFIG_PAX_NOELFRELOCS is not set
CONFIG_PAX_KERNEXEC=y

#
# Address Space Layout Randomization
#
CONFIG_PAX_ASLR=y
CONFIG_PAX_RANDKSTACK=y
CONFIG_PAX_RANDUSTACK=y
CONFIG_PAX_RANDMMAP=y

#
# Miscellaneous hardening features
#
CONFIG_PAX_MEMORY_SANITIZE=y
CONFIG_PAX_MEMORY_UDEREF=y
CONFIG_PAX_REFCOUNT=y
# CONFIG_KEYS is not set
CONFIG_SECURITY=y
CONFIG_SECURITY_NETWORK=y
CONFIG_SECURITY_NETWORK_XFRM=y
CONFIG_SECURITY_FILE_CAPABILITIES=y
CONFIG_SECURITY_DEFAULT_MMAP_MIN_ADDR=0
CONFIG_CRYPTO=y

m.s.tremer wrote:When I finally reboot the system mount gets killed by grsec (with signal 11 - segmentation fault) when mounting /proc, althought /proc gets mounted correctly, and all other pseudo-filesystem (/sys, /dev, /dev/pts), too.

you should set up a chroot and reproduce and debug the segfault there, then we can figure out why mount is crashing.