grsecurity forums

I have opted for a group for /proc restrictions, yet, at least following files remain readable only by root:

cat: /proc/vmstat: Permission denied

This makes running, say, snmpd as non-root bit difficult as it needs access to this file.

Relevant lines from kernel config
CONFIG_GRKERNSEC=y
# CONFIG_GRKERNSEC_LOW is not set
# CONFIG_GRKERNSEC_MEDIUM is not set
# CONFIG_GRKERNSEC_HIGH is not set
CONFIG_GRKERNSEC_CUSTOM=y
CONFIG_GRKERNSEC_KMEM=y
CONFIG_GRKERNSEC_IO=y
CONFIG_GRKERNSEC_PROC_MEMMAP=y
CONFIG_GRKERNSEC_BRUTE=y
CONFIG_GRKERNSEC_MODHARDEN=y
CONFIG_GRKERNSEC_HIDESYM=y
CONFIG_GRKERNSEC_NO_RBAC=y
CONFIG_GRKERNSEC_ACL_HIDEKERN=y
CONFIG_GRKERNSEC_ACL_MAXTRIES=3
CONFIG_GRKERNSEC_ACL_TIMEOUT=30
CONFIG_GRKERNSEC_PROC=y
# CONFIG_GRKERNSEC_PROC_USER is not set
CONFIG_GRKERNSEC_PROC_USERGROUP=y
CONFIG_GRKERNSEC_PROC_GID=4
CONFIG_GRKERNSEC_PROC_ADD=y
CONFIG_GRKERNSEC_LINK=y
CONFIG_GRKERNSEC_FIFO=y
# CONFIG_GRKERNSEC_ROFS is not set
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
# CONFIG_GRKERNSEC_AUDIT_GROUP is not set
# CONFIG_GRKERNSEC_EXECLOG is not set
# CONFIG_GRKERNSEC_RESLOG is not set
# CONFIG_GRKERNSEC_CHROOT_EXECLOG is not set
CONFIG_GRKERNSEC_AUDIT_PTRACE=y
# CONFIG_GRKERNSEC_AUDIT_CHDIR is not set
CONFIG_GRKERNSEC_AUDIT_MOUNT=y
CONFIG_GRKERNSEC_SIGNAL=y
CONFIG_GRKERNSEC_FORKFAIL=y
# CONFIG_GRKERNSEC_TIME is not set
CONFIG_GRKERNSEC_PROC_IPADDR=y
# CONFIG_GRKERNSEC_AUDIT_TEXTREL is not set
CONFIG_GRKERNSEC_EXECVE=y
CONFIG_GRKERNSEC_DMESG=y
CONFIG_GRKERNSEC_HARDEN_PTRACE=y
# CONFIG_GRKERNSEC_TPE is not set
CONFIG_GRKERNSEC_RANDNET=y
CONFIG_GRKERNSEC_BLACKHOLE=y
# CONFIG_GRKERNSEC_SOCKET is not set
CONFIG_GRKERNSEC_SYSCTL=y
# CONFIG_GRKERNSEC_SYSCTL_DISTRO is not set
# CONFIG_GRKERNSEC_SYSCTL_ON is not set
CONFIG_GRKERNSEC_FLOODTIME=10
CONFIG_GRKERNSEC_FLOODBURST=4

For anyone who cares:

you can loosen the restriction a bit by doing following change on mm/vmstat.c:957

#ifdef CONFIG_GRKERNSEC_PROC_ADD
#ifdef CONFIG_GRKERNSEC_PROC_USER
gr_mode = S_IRUSR;
#else
gr_mode = S_IRUSR|S_IRGRP;
#endif
#endif

After this, the group you defined shall have read perms as well. Hooray.

Just curious: do you know what snmpd actually needs /proc/vmstat for?

-Brad

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