Commit 0e1a6ef2 authored Nov 08, 2009 by Kees Cook Committed by James Morris Nov 09, 2009

sysctl: require CAP_SYS_RAWIO to set mmap_min_addr



Currently the mmap_min_addr value can only be bypassed during mmap when
the task has CAP_SYS_RAWIO.  However, the mmap_min_addr sysctl value itself
can be adjusted to 0 if euid == 0, allowing a bypass without CAP_SYS_RAWIO.
This patch adds a check for the capability before allowing mmap_min_addr to
be changed.

Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

parent 31bde71c

security/min_addr.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -33,6 +33,9 @@ int mmap_min_addr_handler(struct ctl_table *table, int write,
		{
		int ret;

		if (!capable(CAP_SYS_RAWIO))
		return -EPERM;

		ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);

		update_mmap_min_addr();