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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: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
Eric Paris 2009-07-31 12:54:05 -04:00 committed by James Morris
parent 9c0d90103c
commit 8cf948e744
1 changed files with 13 additions and 1 deletions
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14
security/selinux/hooks.c
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@ -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;