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authorLorenzo Hernandez García-Hierro <lorenzo@gnu.org>2005-06-25 14:54:34 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-25 16:24:26 -0700
commit6b9921976f0861e04828b3aff66696c1f3fd900d (patch)
treebe372b9dc81e393c909c7fecf8778e8864ba3a0d /security
parent2d15cab85b85a56cc886037cab43cc292923ff22 (diff)
downloadlinux-linaro-stable-6b9921976f0861e04828b3aff66696c1f3fd900d.tar.gz
[PATCH] selinux: add executable stack check
This patch adds an execstack permission check that controls the ability to make the main process stack executable so that attempts to make the stack executable can still be prevented even if the process is allowed the existing execmem permission in order to e.g. perform runtime code generation. Note that this does not yet address thread stacks. Note also that unlike the execmem check, the execstack check is only applied on mprotect calls, not mmap calls, as the current security_file_mmap hook is not passed the necessary information presently. The original author of the code that makes the distinction of the stack region, is Ingo Molnar, who wrote it within his patch for /proc/<pid>/maps markers. (http://marc.theaimsgroup.com/?l=linux-kernel&m=110719881508591&w=2) The patches also can be found at: http://pearls.tuxedo-es.org/patches/selinux/policy-execstack.patch http://pearls.tuxedo-es.org/patches/selinux/kernel-execstack.patch policy-execstack.patch is the patch that needs to be applied to the policy in order to support the execstack permission and exclude it from general_domain_access within macros/core_macros.te. kernel-execstack.patch adds such permission to the SELinux code within the kernel and adds the proper permission check to the selinux_file_mprotect() hook. Signed-off-by: Lorenzo Hernandez Garcia-Hierro <lorenzo@gnu.org> Acked-by: James Morris <jmorris@redhat.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'security')
-rw-r--r--security/selinux/hooks.c10
-rw-r--r--security/selinux/include/av_perm_to_string.h1
-rw-r--r--security/selinux/include/av_permissions.h1
3 files changed, 12 insertions, 0 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 87302a49067b..ad725213f568 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2488,6 +2488,16 @@ static int selinux_file_mprotect(struct vm_area_struct *vma,
if (rc)
return rc;
}
+ if (!vma->vm_file && (prot & PROT_EXEC) &&
+ vma->vm_start <= vma->vm_mm->start_stack &&
+ vma->vm_end >= vma->vm_mm->start_stack) {
+ /* Attempt to make the process stack executable.
+ * This has an additional execstack check.
+ */
+ rc = task_has_perm(current, current, PROCESS__EXECSTACK);
+ if (rc)
+ return rc;
+ }
#endif
return file_map_prot_check(vma->vm_file, prot, vma->vm_flags&VM_SHARED);
diff --git a/security/selinux/include/av_perm_to_string.h b/security/selinux/include/av_perm_to_string.h
index 8928bb4d3c53..e81f0226c37d 100644
--- a/security/selinux/include/av_perm_to_string.h
+++ b/security/selinux/include/av_perm_to_string.h
@@ -70,6 +70,7 @@
S_(SECCLASS_PROCESS, PROCESS__DYNTRANSITION, "dyntransition")
S_(SECCLASS_PROCESS, PROCESS__SETCURRENT, "setcurrent")
S_(SECCLASS_PROCESS, PROCESS__EXECMEM, "execmem")
+ S_(SECCLASS_PROCESS, PROCESS__EXECSTACK, "execstack")
S_(SECCLASS_MSGQ, MSGQ__ENQUEUE, "enqueue")
S_(SECCLASS_MSG, MSG__SEND, "send")
S_(SECCLASS_MSG, MSG__RECEIVE, "receive")
diff --git a/security/selinux/include/av_permissions.h b/security/selinux/include/av_permissions.h
index bdfce4ca8f8e..38ce18b33284 100644
--- a/security/selinux/include/av_permissions.h
+++ b/security/selinux/include/av_permissions.h
@@ -465,6 +465,7 @@
#define PROCESS__DYNTRANSITION 0x00800000UL
#define PROCESS__SETCURRENT 0x01000000UL
#define PROCESS__EXECMEM 0x02000000UL
+#define PROCESS__EXECSTACK 0x04000000UL
#define IPC__CREATE 0x00000001UL
#define IPC__DESTROY 0x00000002UL