On Tue, Nov 01, 2022 at 03:33:11PM -0700, Kees Cook wrote: > Since GCC cannot apply the __alloc_size attributes to inlines[1], all > allocator inlines need to explicitly call into extern functions that > contain a size argument. Provide these wrappers that end up just > ignoring the size argument for the actual allocation. > > This allows CONFIG_FORTIFY_SOURCE=y to see all various dynamic allocation > sizes under GCC 12+ and all supported Clang versions. > > [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96503 > > Cc: Vlastimil Babka <vbabka@xxxxxxx> > Cc: Christoph Lameter <cl@xxxxxxxxx> > Cc: Pekka Enberg <penberg@xxxxxxxxxx> > Cc: David Rientjes <rientjes@xxxxxxxxxx> > Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx> > Cc: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx> > Cc: linux-mm@xxxxxxxxx > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > --- > include/linux/slab.h | 8 ++++++-- > mm/slab_common.c | 14 ++++++++++++++ > 2 files changed, 20 insertions(+), 2 deletions(-) > > diff --git a/include/linux/slab.h b/include/linux/slab.h > index 970e9504949e..051d86ca31a8 100644 > --- a/include/linux/slab.h > +++ b/include/linux/slab.h > @@ -442,6 +442,8 @@ static_assert(PAGE_SHIFT <= 20); > > void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __alloc_size(1); > void *kmem_cache_alloc(struct kmem_cache *s, gfp_t flags) __assume_slab_alignment __malloc; > +void *kmem_cache_alloc_sized(struct kmem_cache *s, gfp_t flags, size_t size) > + __assume_slab_alignment __alloc_size(3); > void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru, > gfp_t gfpflags) __assume_slab_alignment __malloc; > void kmem_cache_free(struct kmem_cache *s, void *objp); > @@ -469,6 +471,8 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignm > __alloc_size(1); > void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node) __assume_slab_alignment > __malloc; > +void *kmem_cache_alloc_node_sized(struct kmem_cache *s, gfp_t flags, int node, size_t size) > + __assume_slab_alignment __alloc_size(4); > > #ifdef CONFIG_TRACING > void *kmalloc_trace(struct kmem_cache *s, gfp_t flags, size_t size) > @@ -482,7 +486,7 @@ void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags, > static __always_inline __alloc_size(3) > void *kmalloc_trace(struct kmem_cache *s, gfp_t flags, size_t size) > { > - void *ret = kmem_cache_alloc(s, flags); > + void *ret = kmem_cache_alloc_sized(s, flags, size); > > ret = kasan_kmalloc(s, ret, size, flags); > return ret; > @@ -492,7 +496,7 @@ static __always_inline __alloc_size(4) > void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags, > int node, size_t size) > { > - void *ret = kmem_cache_alloc_node(s, gfpflags, node); > + void *ret = kmem_cache_alloc_node_sized(s, gfpflags, node, size); > > ret = kasan_kmalloc(s, ret, size, gfpflags); > return ret; > diff --git a/mm/slab_common.c b/mm/slab_common.c > index 33b1886b06eb..5fa547539a6a 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -1457,6 +1457,20 @@ size_t ksize(const void *objp) > } > EXPORT_SYMBOL(ksize); > > +/* Wrapper so __alloc_size() can see the actual allocation size. */ > +void *kmem_cache_alloc_sized(struct kmem_cache *s, gfp_t flags, size_t size) > +{ > + return kmem_cache_alloc(s, flags); > +} > +EXPORT_SYMBOL(kmem_cache_alloc_sized); > + > +/* Wrapper so __alloc_size() can see the actual allocation size. */ > +void *kmem_cache_alloc_node_sized(struct kmem_cache *s, gfp_t flags, int node, size_t size) > +{ > + return kmem_cache_alloc_node(s, flags, node); > +} > +EXPORT_SYMBOL(kmem_cache_alloc_node_sized); The reason that we have two implementations of kmalloc_trace* depending on CONFIG_TRACING is to save additional function call when CONFIG_TRACING is not set. With this patch there is no reason to keep both. So let's drop #ifdefs and use single implementation in mm/slab_common.c. Thanks! > /* Tracepoints definitions. */ > EXPORT_TRACEPOINT_SYMBOL(kmalloc); > EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc); > -- > 2.34.1 > -- Hyeonggon
