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Commit 8cf948e7 authored by Eric Paris's avatar Eric Paris Committed by James Morris
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SELinux: call cap_file_mmap in selinux_file_mmap 



Currently SELinux does not check CAP_SYS_RAWIO in the file_mmap hook.  This
means there is no DAC check on the ability to mmap low addresses in the
memory space.  This function adds the DAC check for CAP_SYS_RAWIO while
maintaining the selinux check on mmap_zero.  This means that processes
which need to mmap low memory will need CAP_SYS_RAWIO and mmap_zero but will
NOT need the SELinux sys_rawio capability.

Signed-off-by: default avatarEric Paris <eparis@redhat.com>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 9c0d9010

security/selinux/hooks.c

+13 −1
Original line number Diff line number Diff line
@@ -3030,9 +3030,21 @@ static int selinux_file_mmap(struct file *file, unsigned long reqprot, 
	int rc = 0;

	u32 sid = current_sid();



	if (addr < mmap_min_addr)

	/*

	 * notice that we are intentionally putting the SELinux check before

	 * the secondary cap_file_mmap check.  This is such a likely attempt

	 * at bad behaviour/exploit that we always want to get the AVC, even

	 * if DAC would have also denied the operation.

	 */

	if (addr < mmap_min_addr) {

		rc = avc_has_perm(sid, sid, SECCLASS_MEMPROTECT,

				  MEMPROTECT__MMAP_ZERO, NULL);

		if (rc)

			return rc;

	}



	/* do DAC check on address space usage */

	rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only);

	if (rc || addr_only)

		return rc;