From: Mathieu Desnoyers Date: Sat, 20 Aug 2011 13:28:32 +0000 (-0400) Subject: shm: Include the returned element length in the range check X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=cba4b7a3bf98faff4c905f71064f7d66b9869e79;p=ust.git shm: Include the returned element length in the range check Signed-off-by: Mathieu Desnoyers --- diff --git a/libringbuffer/shm.h b/libringbuffer/shm.h index f5cc8e6..9f72a5a 100644 --- a/libringbuffer/shm.h +++ b/libringbuffer/shm.h @@ -20,26 +20,27 @@ */ static inline char *_shmp_offset(struct shm_object_table *table, struct shm_ref *ref, - size_t offset) + size_t idx, size_t elem_size) { struct shm_object *obj; - size_t index, ref_offset; + size_t objindex, ref_offset; - index = (size_t) ref->index; - if (unlikely(index >= table->allocated_len)) + objindex = (size_t) ref->index; + if (unlikely(objindex >= table->allocated_len)) return NULL; - obj = &table->objects[index]; + obj = &table->objects[objindex]; ref_offset = (size_t) ref->offset; - ref_offset += offset; - if (unlikely(ref_offset >= obj->memory_map_size)) + ref_offset += idx * elem_size; + /* Check if part of the element returned would exceed the limits. */ + if (unlikely(ref_offset + elem_size > obj->memory_map_size)) return NULL; return &obj->memory_map[ref_offset]; } -#define shmp_index(handle, ref, offset) \ +#define shmp_index(handle, ref, index) \ ({ \ __typeof__((ref)._type) ____ptr_ret; \ - ____ptr_ret = (__typeof__(____ptr_ret)) _shmp_offset((handle)->table, &(ref)._ref, ((offset) * sizeof(*____ptr_ret))); \ + ____ptr_ret = (__typeof__(____ptr_ret)) _shmp_offset((handle)->table, &(ref)._ref, index, sizeof(*____ptr_ret)); \ ____ptr_ret; \ })