[PATCH 4/5] mm: poison vm_area_struct
From: Sasha Levin
Date: Mon Sep 29 2014 - 21:48:19 EST
Add poisoning to vm_area_struct to catch corruption at either the beginning or
the end of the struct.
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
fs/exec.c | 5 +++++
include/linux/mm_types.h | 6 ++++++
include/linux/mmdebug.h | 6 ++++++
kernel/fork.c | 2 ++
mm/debug.c | 11 +++++++++--
mm/mmap.c | 19 ++++++++++++++++++-
mm/nommu.c | 7 +++++++
mm/vmacache.c | 3 +++
8 files changed, 56 insertions(+), 3 deletions(-)
diff --git a/fs/exec.c b/fs/exec.c
index 7302b75..6cdd652 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -257,6 +257,10 @@ static int __bprm_mm_init(struct linux_binprm *bprm)
return -ENOMEM;
down_write(&mm->mmap_sem);
+#ifdef CONFIG_DEBUG_VM_POISON
+ vma->poison_start = MM_POISON_BEGIN;
+ vma->poison_end = MM_POISON_END;
+#endif
vma->vm_mm = mm;
/*
@@ -283,6 +287,7 @@ static int __bprm_mm_init(struct linux_binprm *bprm)
err:
up_write(&mm->mmap_sem);
bprm->vma = NULL;
+ VM_CHECK_POISON_VMA(vma);
kmem_cache_free(vm_area_cachep, vma);
return err;
}
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 0b0d324..4e2cf93 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -245,6 +245,9 @@ struct vm_region {
* library, the executable area etc).
*/
struct vm_area_struct {
+#ifdef CONFIG_DEBUG_VM_POISON
+ u32 poison_start;
+#endif
/* The first cache line has the info for VMA tree walking. */
unsigned long vm_start; /* Our start address within vm_mm. */
@@ -308,6 +311,9 @@ struct vm_area_struct {
#ifdef CONFIG_NUMA
struct mempolicy *vm_policy; /* NUMA policy for the VMA */
#endif
+#ifdef CONFIG_DEBUG_VM_POISON
+ u32 poison_end;
+#endif
};
struct core_thread {
diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index 339e40f..75bc69d 100644
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -45,6 +45,11 @@ void dump_mm(const struct mm_struct *mm);
VM_BUG_ON_MM((mm)->poison_start != MM_POISON_BEGIN, (mm));\
VM_BUG_ON_MM((mm)->poison_end != MM_POISON_END, (mm)); \
} while (0)
+#define VM_CHECK_POISON_VMA(vma) \
+ do { \
+ VM_BUG_ON_VMA((vma)->poison_start != MM_POISON_BEGIN, (vma));\
+ VM_BUG_ON_VMA((vma)->poison_end != MM_POISON_END, (vma));\
+ } while (0)
#endif
#else
#define VM_BUG_ON(cond) BUILD_BUG_ON_INVALID(cond)
@@ -55,6 +60,7 @@ void dump_mm(const struct mm_struct *mm);
#define VM_WARN_ON_ONCE(cond) BUILD_BUG_ON_INVALID(cond)
#define VM_WARN_ONCE(cond, format...) BUILD_BUG_ON_INVALID(cond)
#define VM_CHECK_POISON_MM(mm) do { } while(0)
+#define VM_CHECK_POISON_VMA(vma) do { } while(0)
#endif
#ifdef CONFIG_DEBUG_VIRTUAL
diff --git a/kernel/fork.c b/kernel/fork.c
index 26bedfa..c3ae913 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -415,6 +415,7 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
if (!tmp)
goto fail_nomem;
+ VM_CHECK_POISON_VMA(mpnt);
*tmp = *mpnt;
INIT_LIST_HEAD(&tmp->anon_vma_chain);
retval = vma_dup_policy(mpnt, tmp);
@@ -489,6 +490,7 @@ out:
fail_nomem_anon_vma_fork:
mpol_put(vma_policy(tmp));
fail_nomem_policy:
+ VM_CHECK_POISON_VMA(tmp);
kmem_cache_free(vm_area_cachep, tmp);
fail_nomem:
retval = -ENOMEM;
diff --git a/mm/debug.c b/mm/debug.c
index a1ebc5e..d53174e 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -152,11 +152,18 @@ static const struct trace_print_flags vmaflags_names[] = {
void dump_vma(const struct vm_area_struct *vma)
{
pr_emerg("vma %p start %p end %p\n"
+#ifdef CONFIG_DEBUG_VM_POISON
+ "start poison: %s end poison: %s\n"
+#endif
"next %p prev %p mm %p\n"
"prot %lx anon_vma %p vm_ops %p\n"
"pgoff %lx file %p private_data %p\n",
- vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_next,
- vma->vm_prev, vma->vm_mm,
+ vma, (void *)vma->vm_start, (void *)vma->vm_end,
+#ifdef CONFIG_DEBUG_VM_POISON
+ (vma->poison_start == MM_POISON_BEGIN) ? "valid" : "invalid",
+ (vma->poison_end == MM_POISON_END) ? "valid" : "invalid",
+#endif
+ vma->vm_next, vma->vm_prev, vma->vm_mm,
(unsigned long)pgprot_val(vma->vm_page_prot),
vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
vma->vm_file, vma->vm_private_data);
diff --git a/mm/mmap.c b/mm/mmap.c
index 3240bbc..da5ffeb 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -274,6 +274,7 @@ static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
struct vm_area_struct *next = vma->vm_next;
might_sleep();
+ VM_CHECK_POISON_VMA(vma);
if (vma->vm_ops && vma->vm_ops->close)
vma->vm_ops->close(vma);
if (vma->vm_file)
@@ -900,6 +901,7 @@ again: remove_next = 1 + (end > next->vm_end);
anon_vma_merge(vma, next);
mm->map_count--;
mpol_put(vma_policy(next));
+ VM_CHECK_POISON_VMA(next);
kmem_cache_free(vm_area_cachep, next);
/*
* In mprotect's case 6 (see comments on vma_merge),
@@ -1594,6 +1596,10 @@ munmap_back:
goto unacct_error;
}
+#ifdef CONFIG_DEBUG_VM_POISON
+ vma->poison_start = MM_POISON_BEGIN;
+ vma->poison_end = MM_POISON_END;
+#endif
vma->vm_mm = mm;
vma->vm_start = addr;
vma->vm_end = addr + len;
@@ -1691,6 +1697,7 @@ allow_write_and_free_vma:
if (vm_flags & VM_DENYWRITE)
allow_write_access(file);
free_vma:
+ VM_CHECK_POISON_VMA(vma);
kmem_cache_free(vm_area_cachep, vma);
unacct_error:
if (charged)
@@ -2454,7 +2461,7 @@ static int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
if (!new)
goto out_err;
-
+ VM_CHECK_POISON_VMA(vma);
/* most fields are the same, copy all, and then fixup */
*new = *vma;
@@ -2499,6 +2506,7 @@ static int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
out_free_mpol:
mpol_put(vma_policy(new));
out_free_vma:
+ VM_CHECK_POISON_VMA(new);
kmem_cache_free(vm_area_cachep, new);
out_err:
return err;
@@ -2771,6 +2779,10 @@ static unsigned long do_brk(unsigned long addr, unsigned long len)
return -ENOMEM;
}
+#ifdef CONFIG_DEBUG_VM_POISON
+ vma->poison_start = MM_POISON_BEGIN;
+ vma->poison_end = MM_POISON_END;
+#endif
INIT_LIST_HEAD(&vma->anon_vma_chain);
vma->vm_mm = mm;
vma->vm_start = addr;
@@ -2942,6 +2954,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
*need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff);
} else {
new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
+ VM_CHECK_POISON_VMA(vma);
if (new_vma) {
*new_vma = *vma;
new_vma->vm_start = addr;
@@ -3058,6 +3071,10 @@ static struct vm_area_struct *__install_special_mapping(
return ERR_PTR(-ENOMEM);
INIT_LIST_HEAD(&vma->anon_vma_chain);
+#ifdef CONFIG_DEBUG_VM_POISON
+ vma->poison_start = MM_POISON_BEGIN;
+ vma->poison_end = MM_POISON_END;
+#endif
vma->vm_mm = mm;
vma->vm_start = addr;
vma->vm_end = addr + len;
diff --git a/mm/nommu.c b/mm/nommu.c
index bd10aa1..e81b656 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -820,6 +820,7 @@ static void delete_vma_from_mm(struct vm_area_struct *vma)
static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
{
kenter("%p", vma);
+ VM_CHECK_POISON_VMA(vma);
if (vma->vm_ops && vma->vm_ops->close)
vma->vm_ops->close(vma);
if (vma->vm_file)
@@ -1302,6 +1303,10 @@ unsigned long do_mmap_pgoff(struct file *file,
if (!vma)
goto error_getting_vma;
+#ifdef CONFIG_DEBUG_VM_POISON
+ vma->poison_start = MM_POISON_BEGIN;
+ vma->poison_end = MM_POISON_END;
+#endif
region->vm_usage = 1;
region->vm_flags = vm_flags;
region->vm_pgoff = pgoff;
@@ -1465,6 +1470,7 @@ error:
kmem_cache_free(vm_region_jar, region);
if (vma->vm_file)
fput(vma->vm_file);
+ VM_CHECK_POISON_VMA(vma);
kmem_cache_free(vm_area_cachep, vma);
kleave(" = %d", ret);
return ret;
@@ -1571,6 +1577,7 @@ int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
}
/* most fields are the same, copy all, and then fixup */
+ VM_CHECK_POISON_VMA(vma);
*new = *vma;
*region = *vma->vm_region;
new->vm_region = region;
diff --git a/mm/vmacache.c b/mm/vmacache.c
index d507caa..27760cf 100644
--- a/mm/vmacache.c
+++ b/mm/vmacache.c
@@ -59,6 +59,7 @@ static bool vmacache_valid_mm(struct mm_struct *mm)
void vmacache_update(unsigned long addr, struct vm_area_struct *newvma)
{
+ VM_CHECK_POISON_VMA(newvma);
if (vmacache_valid_mm(newvma->vm_mm))
current->vmacache[VMACACHE_HASH(addr)] = newvma;
}
@@ -99,6 +100,7 @@ struct vm_area_struct *vmacache_find(struct mm_struct *mm, unsigned long addr)
continue;
if (WARN_ON_ONCE(vma->vm_mm != mm))
break;
+ VM_CHECK_POISON_VMA(vma);
if (vma->vm_start <= addr && vma->vm_end > addr) {
count_vm_vmacache_event(VMACACHE_FIND_HITS);
return vma;
@@ -123,6 +125,7 @@ struct vm_area_struct *vmacache_find_exact(struct mm_struct *mm,
for (i = 0; i < VMACACHE_SIZE; i++) {
struct vm_area_struct *vma = current->vmacache[i];
+ VM_CHECK_POISON_VMA(vma);
if (vma && vma->vm_start == start && vma->vm_end == end) {
count_vm_vmacache_event(VMACACHE_FIND_HITS);
return vma;
--
1.9.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/