diff options
author | Stephen Smalley <sds@tycho.nsa.gov> | 2010-04-28 23:57:57 +0400 |
---|---|---|
committer | James Morris <jmorris@namei.org> | 2010-04-29 02:58:45 +0400 |
commit | fcaaade1db63bb2d6f7611d7824eb50d2f07a546 (patch) | |
tree | 9091dbdd0c9bd1e3af9ece6f5cce5c0d6c258253 /security | |
parent | cb84aa9b42b506299e5aea1ba4da26c03ab12877 (diff) | |
download | linux-fcaaade1db63bb2d6f7611d7824eb50d2f07a546.tar.xz |
selinux: generalize disabling of execmem for plt-in-heap archs
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>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security')
-rw-r--r-- | security/selinux/hooks.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index ebee467e2913..a03fd74602b4 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); |