From 09ffd94fb15d85fbf9eebb8180f50264b264d6fe Mon Sep 17 00:00:00 2001 From: Lorenzo Hernández García-Hierro Date: Sat, 25 Jun 2005 14:54:35 -0700 Subject: [PATCH] selinux: add executable heap check This patch,based on sample code by Roland McGrath, adds an execheap permission check that controls the ability to make the heap executable so that this can be prevented in almost all cases (the X server is presently an exception, but this will hopefully be resolved in the future) so that even programs with execmem permission will need to have the anonymous memory mapped in order to make it executable. The only reason that we use a permission check for such restriction (vs. making it unconditional) is that the X module loader presently needs it; it could possibly be made unconditional in the future when X is changed. The policy patch for the execheap permission is available at: http://pearls.tuxedo-es.org/patches/selinux/policy-execheap.patch Signed-off-by: Lorenzo Hernandez Garcia-Hierro Acked-by: James Morris Acked-by: Stephen Smalley Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- security/selinux/hooks.c | 11 +++++++++++ security/selinux/include/av_perm_to_string.h | 1 + security/selinux/include/av_permissions.h | 1 + 3 files changed, 13 insertions(+) (limited to 'security/selinux') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index ad725213f568..932eef18db33 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2477,6 +2477,17 @@ static int selinux_file_mprotect(struct vm_area_struct *vma, prot = reqprot; #ifndef CONFIG_PPC32 + if ((prot & PROT_EXEC) && !(vma->vm_flags & VM_EXECUTABLE) && + (vma->vm_start >= vma->vm_mm->start_brk && + vma->vm_end <= vma->vm_mm->brk)) { + /* + * We are making an executable mapping in the brk region. + * This has an additional execheap check. + */ + rc = task_has_perm(current, current, PROCESS__EXECHEAP); + if (rc) + return rc; + } if (vma->vm_file != NULL && vma->anon_vma != NULL && (prot & PROT_EXEC)) { /* * We are making executable a file mapping that has diff --git a/security/selinux/include/av_perm_to_string.h b/security/selinux/include/av_perm_to_string.h index e81f0226c37d..1deb59e1b762 100644 --- a/security/selinux/include/av_perm_to_string.h +++ b/security/selinux/include/av_perm_to_string.h @@ -71,6 +71,7 @@ S_(SECCLASS_PROCESS, PROCESS__SETCURRENT, "setcurrent") S_(SECCLASS_PROCESS, PROCESS__EXECMEM, "execmem") S_(SECCLASS_PROCESS, PROCESS__EXECSTACK, "execstack") + S_(SECCLASS_PROCESS, PROCESS__EXECHEAP, "execheap") 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 38ce18b33284..a78b5d59c9fc 100644 --- a/security/selinux/include/av_permissions.h +++ b/security/selinux/include/av_permissions.h @@ -466,6 +466,7 @@ #define PROCESS__SETCURRENT 0x01000000UL #define PROCESS__EXECMEM 0x02000000UL #define PROCESS__EXECSTACK 0x04000000UL +#define PROCESS__EXECHEAP 0x08000000UL #define IPC__CREATE 0x00000001UL #define IPC__DESTROY 0x00000002UL -- cgit v1.2.3