| Message ID | a13a41e3ca65116eb5614c4dd396b23182e98fed.1535462971.git.andreyknvl@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | khwasan: kernel hardware assisted address sanitizer | expand |
Reviewed-by: Christoph Lameter <cl@linux.com> On Wed, 29 Aug 2018, Andrey Konovalov wrote: > The krealloc function checks where the same buffer was reused or a new one > allocated by comparing kernel pointers. KHWASAN changes memory tag on the > krealloc'ed chunk of memory and therefore also changes the pointer tag of > the returned pointer. Therefore we need to perform comparison on untagged > (with tags reset) pointers to check whether it's the same memory region or > not. > > Signed-off-by: Andrey Konovalov <andreyknvl@google.com> > --- > mm/slab_common.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/slab_common.c b/mm/slab_common.c > index 3abfa0f86118..0d588dfebd7d 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -1513,7 +1513,7 @@ void *krealloc(const void *p, size_t new_size, gfp_t flags) > } > > ret = __do_krealloc(p, new_size, flags); > - if (ret && p != ret) > + if (ret && khwasan_reset_tag(p) != khwasan_reset_tag(ret)) > kfree(p); > > return ret; >
diff --git a/mm/slab_common.c b/mm/slab_common.c index 3abfa0f86118..0d588dfebd7d 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -1513,7 +1513,7 @@ void *krealloc(const void *p, size_t new_size, gfp_t flags) } ret = __do_krealloc(p, new_size, flags); - if (ret && p != ret) + if (ret && khwasan_reset_tag(p) != khwasan_reset_tag(ret)) kfree(p); return ret;
The krealloc function checks where the same buffer was reused or a new one allocated by comparing kernel pointers. KHWASAN changes memory tag on the krealloc'ed chunk of memory and therefore also changes the pointer tag of the returned pointer. Therefore we need to perform comparison on untagged (with tags reset) pointers to check whether it's the same memory region or not. Signed-off-by: Andrey Konovalov <andreyknvl@google.com> --- mm/slab_common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)