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authorJesse Keating <jkeating@redhat.com>2010-07-29 16:46:31 -0700
committerJesse Keating <jkeating@redhat.com>2010-07-29 16:46:31 -0700
commit7a32965a104c3363e8505fe566531fcf071cced7 (patch)
treee45cb84552b2b022f49047bbddd9d887753c35bc /linux-2.6-selinux-mprotect-checks.patch
parent64ba2e5ffde5f2418eb26c700cb0ab62b04e5013 (diff)
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Diffstat (limited to 'linux-2.6-selinux-mprotect-checks.patch')
-rw-r--r--linux-2.6-selinux-mprotect-checks.patch124
1 files changed, 124 insertions, 0 deletions
diff --git a/linux-2.6-selinux-mprotect-checks.patch b/linux-2.6-selinux-mprotect-checks.patch
new file mode 100644
index 000000000..010a63c43
--- /dev/null
+++ b/linux-2.6-selinux-mprotect-checks.patch
@@ -0,0 +1,124 @@
+This needs a fixed toolchain, and a userspace rebuild to work.
+For these reasons, it's had difficulty getting upstream.
+
+ie, Fedora has a new enough toolchain, and has been rebuilt, so we don't need
+the ifdefs. Other distros don't/haven't, and this patch would break them
+if pushed upstream.
+
+
+Subject: [Fwd: Re: [PATCH] Disable execmem for sparc]
+From: Stephen Smalley <sds@tycho.nsa.gov>
+To: Dave Jones <davej@redhat.com>
+Date: Wed, 28 Apr 2010 16:04:56 -0400
+Message-Id: <1272485096.6013.326.camel@moss-pluto.epoch.ncsc.mil>
+
+-------- Forwarded Message --------
+From: Stephen Smalley <sds@tycho.nsa.gov>
+To: David Miller <davem@davemloft.net>
+Cc: tcallawa@redhat.com, dennis@ausil.us, sparclinux@vger.kernel.org, dgilmore@redhat.com, jmorris@namei.org, eparis@parisplace.org
+Subject: Re: [PATCH] Disable execmem for sparc
+Date: Wed, 28 Apr 2010 15:57:57 -0400
+
+On Tue, 2010-04-27 at 11:47 -0700, David Miller wrote:
+> From: "Tom \"spot\" Callaway" <tcallawa@redhat.com>
+> Date: Tue, 27 Apr 2010 14:20:21 -0400
+>
+> > [root@apollo ~]$ cat /proc/2174/maps
+> > 00010000-00014000 r-xp 00000000 fd:00 15466577
+> > /sbin/mingetty
+> > 00022000-00024000 rwxp 00002000 fd:00 15466577
+> > /sbin/mingetty
+> > 00024000-00046000 rwxp 00000000 00:00 0
+> > [heap]
+>
+> SELINUX probably barfs on the executable heap, the PLT is in the HEAP
+> just like powerpc32 and that's why VM_DATA_DEFAULT_FLAGS has to set
+> both executable and writable.
+>
+> You also can't remove the CONFIG_PPC32 ifdefs in selinux, since
+> because of the VM_DATA_DEFAULT_FLAGS setting used still in that arch,
+> the heap will always have executable permission, just like sparc does.
+> You have to support those binaries forever, whether you like it or not.
+>
+> Let's just replace the CONFIG_PPC32 ifdef in SELINUX with CONFIG_PPC32
+> || CONFIG_SPARC as in Tom's original patch and let's be done with
+> this.
+>
+> In fact I would go through all the arch/ header files and check the
+> VM_DATA_DEFAULT_FLAGS settings and add the necessary new ifdefs to the
+> SELINUX code so that other platforms don't have the pain of having to
+> go through this process too.
+
+To avoid maintaining per-arch ifdefs, it seems that we could just
+directly use (VM_DATA_DEFAULT_FLAGS & VM_EXEC) as the basis for deciding
+whether to enable or disable these checks. VM_DATA_DEFAULT_FLAGS isn't
+constant on some architectures but instead depends on
+current->personality, but we want this applied uniformly. So we'll just
+use the initial task state to determine whether or not to enable these
+checks.
+
+Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
+
+diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
+index ebee467..a03fd74 100644
+--- a/security/selinux/hooks.c
++++ b/security/selinux/hooks.c
+@@ -2999,13 +2999,15 @@ static int selinux_file_ioctl(struct file *file, unsigned int cmd,
+ return file_has_perm(cred, file, av);
+ }
+
++static int default_noexec;
++
+ static int file_map_prot_check(struct file *file, unsigned long prot, int shared)
+ {
+ const struct cred *cred = current_cred();
+ int rc = 0;
+
+-#ifndef CONFIG_PPC32
+- if ((prot & PROT_EXEC) && (!file || (!shared && (prot & PROT_WRITE)))) {
++ if (default_noexec &&
++ (prot & PROT_EXEC) && (!file || (!shared && (prot & PROT_WRITE)))) {
+ /*
+ * We are making executable an anonymous mapping or a
+ * private file mapping that will also be writable.
+@@ -3015,7 +3017,6 @@ static int file_map_prot_check(struct file *file, unsigned long prot, int shared
+ if (rc)
+ goto error;
+ }
+-#endif
+
+ if (file) {
+ /* read access is always possible with a mapping */
+@@ -3076,8 +3077,8 @@ static int selinux_file_mprotect(struct vm_area_struct *vma,
+ if (selinux_checkreqprot)
+ prot = reqprot;
+
+-#ifndef CONFIG_PPC32
+- if ((prot & PROT_EXEC) && !(vma->vm_flags & VM_EXEC)) {
++ if (default_noexec &&
++ (prot & PROT_EXEC) && !(vma->vm_flags & VM_EXEC)) {
+ int rc = 0;
+ if (vma->vm_start >= vma->vm_mm->start_brk &&
+ vma->vm_end <= vma->vm_mm->brk) {
+@@ -3099,7 +3100,6 @@ static int selinux_file_mprotect(struct vm_area_struct *vma,
+ if (rc)
+ return rc;
+ }
+-#endif
+
+ return file_map_prot_check(vma->vm_file, prot, vma->vm_flags&VM_SHARED);
+ }
+@@ -5662,6 +5662,8 @@ static __init int selinux_init(void)
+ /* Set the security state for the initial task. */
+ cred_init_security();
+
++ default_noexec = !(VM_DATA_DEFAULT_FLAGS & VM_EXEC);
++
+ sel_inode_cache = kmem_cache_create("selinux_inode_security",
+ sizeof(struct inode_security_struct),
+ 0, SLAB_PANIC, NULL);
+
+--
+Stephen Smalley
+National Security Agency
+