| Message ID | 20240808130909.1027860-1-wangkefeng.wang@huawei.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Paul Moore |
| Headers | show |
| Series | Revert "selinux: use vma_is_initial_stack() and vma_is_initial_heap()" | expand |
On Thu, Aug 8, 2024 at 9:09 AM Kefeng Wang <wangkefeng.wang@huawei.com> wrote: > > This reverts commit 68df1baf158fddc07b6f0333e4c81fe1ccecd6ff. > > The selinux only want to check whether the VMA range is within the heap > range or not, but vma_is_initial_heap() helper will check the intersection > between the two ranges, which leads to some issue, let's turn back to the > original validation. > > Reported-by: Marc Reisner <reisner.marc@gmail.com> > Closes: https://lore.kernel.org/all/ZrPmoLKJEf1wiFmM@marcreisner.com/ > Fixes: 68df1baf158f ("selinux: use vma_is_initial_stack() and vma_is_initial_heap()") > Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> I was only going to recommend reverting the change to the heap check but in case Paul is fine with a straight revert, Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com> > --- > security/selinux/hooks.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c > index 81fbfa5b80d4..f5805d4b0aec 100644 > --- a/security/selinux/hooks.c > +++ b/security/selinux/hooks.c > @@ -3845,10 +3845,13 @@ static int selinux_file_mprotect(struct vm_area_struct *vma, > if (default_noexec && > (prot & PROT_EXEC) && !(vma->vm_flags & VM_EXEC)) { > int rc = 0; > - if (vma_is_initial_heap(vma)) { > + if (vma->vm_start >= vma->vm_mm->start_brk && > + vma->vm_end <= vma->vm_mm->brk) { > rc = avc_has_perm(sid, sid, SECCLASS_PROCESS, > PROCESS__EXECHEAP, NULL); > - } else if (!vma->vm_file && (vma_is_initial_stack(vma) || > + } else if (!vma->vm_file && > + ((vma->vm_start <= vma->vm_mm->start_stack && > + vma->vm_end >= vma->vm_mm->start_stack) || > vma_is_stack_for_current(vma))) { > rc = avc_has_perm(sid, sid, SECCLASS_PROCESS, > PROCESS__EXECSTACK, NULL); > -- > 2.41.0 >
On Thu, Aug 8, 2024 at 9:40 AM Stephen Smalley <stephen.smalley.work@gmail.com> wrote: > > On Thu, Aug 8, 2024 at 9:09 AM Kefeng Wang <wangkefeng.wang@huawei.com> wrote: > > > > This reverts commit 68df1baf158fddc07b6f0333e4c81fe1ccecd6ff. > > > > The selinux only want to check whether the VMA range is within the heap > > range or not, but vma_is_initial_heap() helper will check the intersection > > between the two ranges, which leads to some issue, let's turn back to the > > original validation. > > > > Reported-by: Marc Reisner <reisner.marc@gmail.com> > > Closes: https://lore.kernel.org/all/ZrPmoLKJEf1wiFmM@marcreisner.com/ > > Fixes: 68df1baf158f ("selinux: use vma_is_initial_stack() and vma_is_initial_heap()") > > Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> > > I was only going to recommend reverting the change to the heap check > but in case Paul is fine with a straight revert, > Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com> I was hoping that the mm folks would put together a quick patch to fix what looks like a problem with the helper, but I'm not sure when that is going to happen and with other callers I don't want to change the helper and break a different part of the kernel. Unfortunately that leaves us with needing a revert, but like Stephen said, I think reverting just the heap helper is the right thing to do right now; I also want to put a comment in there for the next time someone tries to re-add the vma_is_initial_heap(). Give me some time, I'll have a patch out for this later today. > > --- > > security/selinux/hooks.c | 7 +++++-- > > 1 file changed, 5 insertions(+), 2 deletions(-) > > > > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c > > index 81fbfa5b80d4..f5805d4b0aec 100644 > > --- a/security/selinux/hooks.c > > +++ b/security/selinux/hooks.c > > @@ -3845,10 +3845,13 @@ static int selinux_file_mprotect(struct vm_area_struct *vma, > > if (default_noexec && > > (prot & PROT_EXEC) && !(vma->vm_flags & VM_EXEC)) { > > int rc = 0; > > - if (vma_is_initial_heap(vma)) { > > + if (vma->vm_start >= vma->vm_mm->start_brk && > > + vma->vm_end <= vma->vm_mm->brk) { > > rc = avc_has_perm(sid, sid, SECCLASS_PROCESS, > > PROCESS__EXECHEAP, NULL); > > - } else if (!vma->vm_file && (vma_is_initial_stack(vma) || > > + } else if (!vma->vm_file && > > + ((vma->vm_start <= vma->vm_mm->start_stack && > > + vma->vm_end >= vma->vm_mm->start_stack) || > > vma_is_stack_for_current(vma))) { > > rc = avc_has_perm(sid, sid, SECCLASS_PROCESS, > > PROCESS__EXECSTACK, NULL); > > -- > > 2.41.0 -- paul-moore.com
On Thu, Aug 8, 2024 at 11:48 AM Paul Moore <paul@paul-moore.com> wrote: > > On Thu, Aug 8, 2024 at 9:40 AM Stephen Smalley > <stephen.smalley.work@gmail.com> wrote: > > > > On Thu, Aug 8, 2024 at 9:09 AM Kefeng Wang <wangkefeng.wang@huawei.com> wrote: > > > > > > This reverts commit 68df1baf158fddc07b6f0333e4c81fe1ccecd6ff. > > > > > > The selinux only want to check whether the VMA range is within the heap > > > range or not, but vma_is_initial_heap() helper will check the intersection > > > between the two ranges, which leads to some issue, let's turn back to the > > > original validation. > > > > > > Reported-by: Marc Reisner <reisner.marc@gmail.com> > > > Closes: https://lore.kernel.org/all/ZrPmoLKJEf1wiFmM@marcreisner.com/ > > > Fixes: 68df1baf158f ("selinux: use vma_is_initial_stack() and vma_is_initial_heap()") > > > Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> > > > > I was only going to recommend reverting the change to the heap check > > but in case Paul is fine with a straight revert, > > Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com> > > I was hoping that the mm folks would put together a quick patch to fix > what looks like a problem with the helper, but I'm not sure when that > is going to happen and with other callers I don't want to change the > helper and break a different part of the kernel. Unfortunately that > leaves us with needing a revert, but like Stephen said, I think > reverting just the heap helper is the right thing to do right now; I > also want to put a comment in there for the next time someone tries to > re-add the vma_is_initial_heap(). Give me some time, I'll have a > patch out for this later today. FWIW, I tossed the reproducer code from Marc Reisner into a branch of the SELinux testsuite and wrapped it up with an added test to the mmap tests here: https://github.com/stephensmalley/selinux-testsuite/tree/execheapregression Passes with the revert, fails without. Would need to be modified to be portable to actually be suitable for inclusion though.
On Thu, Aug 8, 2024 at 2:54 PM Stephen Smalley <stephen.smalley.work@gmail.com> wrote: > On Thu, Aug 8, 2024 at 11:48 AM Paul Moore <paul@paul-moore.com> wrote: > > On Thu, Aug 8, 2024 at 9:40 AM Stephen Smalley > > <stephen.smalley.work@gmail.com> wrote: > > > > > > On Thu, Aug 8, 2024 at 9:09 AM Kefeng Wang <wangkefeng.wang@huawei.com> wrote: > > > > > > > > This reverts commit 68df1baf158fddc07b6f0333e4c81fe1ccecd6ff. > > > > > > > > The selinux only want to check whether the VMA range is within the heap > > > > range or not, but vma_is_initial_heap() helper will check the intersection > > > > between the two ranges, which leads to some issue, let's turn back to the > > > > original validation. > > > > > > > > Reported-by: Marc Reisner <reisner.marc@gmail.com> > > > > Closes: https://lore.kernel.org/all/ZrPmoLKJEf1wiFmM@marcreisner.com/ > > > > Fixes: 68df1baf158f ("selinux: use vma_is_initial_stack() and vma_is_initial_heap()") > > > > Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> > > > > > > I was only going to recommend reverting the change to the heap check > > > but in case Paul is fine with a straight revert, > > > Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com> > > > > I was hoping that the mm folks would put together a quick patch to fix > > what looks like a problem with the helper, but I'm not sure when that > > is going to happen and with other callers I don't want to change the > > helper and break a different part of the kernel. Unfortunately that > > leaves us with needing a revert, but like Stephen said, I think > > reverting just the heap helper is the right thing to do right now; I > > also want to put a comment in there for the next time someone tries to > > re-add the vma_is_initial_heap(). Give me some time, I'll have a > > patch out for this later today. > > FWIW, I tossed the reproducer code from Marc Reisner into a branch of > the SELinux testsuite and wrapped it up with an added test to the mmap > tests here: > https://github.com/stephensmalley/selinux-testsuite/tree/execheapregression > > Passes with the revert, fails without. > Would need to be modified to be portable to actually be suitable for > inclusion though. Thanks Stephen. FWIW, I think improving this test such that it could be included in the test suite would be a very good thing to do.
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 81fbfa5b80d4..f5805d4b0aec 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3845,10 +3845,13 @@ static int selinux_file_mprotect(struct vm_area_struct *vma, if (default_noexec && (prot & PROT_EXEC) && !(vma->vm_flags & VM_EXEC)) { int rc = 0; - if (vma_is_initial_heap(vma)) { + if (vma->vm_start >= vma->vm_mm->start_brk && + vma->vm_end <= vma->vm_mm->brk) { rc = avc_has_perm(sid, sid, SECCLASS_PROCESS, PROCESS__EXECHEAP, NULL); - } else if (!vma->vm_file && (vma_is_initial_stack(vma) || + } else if (!vma->vm_file && + ((vma->vm_start <= vma->vm_mm->start_stack && + vma->vm_end >= vma->vm_mm->start_stack) || vma_is_stack_for_current(vma))) { rc = avc_has_perm(sid, sid, SECCLASS_PROCESS, PROCESS__EXECSTACK, NULL);
This reverts commit 68df1baf158fddc07b6f0333e4c81fe1ccecd6ff. The selinux only want to check whether the VMA range is within the heap range or not, but vma_is_initial_heap() helper will check the intersection between the two ranges, which leads to some issue, let's turn back to the original validation. Reported-by: Marc Reisner <reisner.marc@gmail.com> Closes: https://lore.kernel.org/all/ZrPmoLKJEf1wiFmM@marcreisner.com/ Fixes: 68df1baf158f ("selinux: use vma_is_initial_stack() and vma_is_initial_heap()") Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> --- security/selinux/hooks.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)