diff options
Diffstat (limited to 'linux-2.6-selinux-mprotect-checks.patch')
| -rw-r--r-- | linux-2.6-selinux-mprotect-checks.patch | 124 |
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 + |