mempool system clean: Don't break if realloc() shrinks the memory area.

--HG--
branch : HEAD

diff --git a/src/lib/mempool-system-clean.c b/src/lib/mempool-system-clean.c
index 11dd472e5041ede246252ca12464e924334ffa41..49f817b658f60d81784131fc5f21939717123aec 100644 (file)
--- a/src/lib/mempool-system-clean.c
+++ b/src/lib/mempool-system-clean.c
@@ -136,6 +136,7 @@ static void *pool_system_clean_realloc(pool_t pool ATTR_UNUSED, void *mem,
                                       size_t old_size, size_t new_size)
 {
        void *new_mem;
+       size_t old_alloc_size;
 
        if (unlikely(new_size == 0 || new_size > SSIZE_T_MAX))
                i_panic("Trying to allocate %"PRIuSIZE_T" bytes", new_size);
@@ -146,14 +147,15 @@ static void *pool_system_clean_realloc(pool_t pool ATTR_UNUSED, void *mem,
                i_assert(old_size == (size_t)-1 ||
                         old_size <= malloc_usable_size(mem));
 #endif
-               memcpy(new_mem, mem, mem_get_size(mem));
-               pool_system_clean_free(pool, mem);
+               old_alloc_size = mem_get_size(mem);
+               memcpy(new_mem, mem, I_MIN(old_alloc_size, new_size));
 
                if (old_size < new_size) {
                        /* clear new data */
                        memset((char *)new_mem + old_size, 0,
                               new_size - old_size);
                }
+               pool_system_clean_free(pool, mem);
        }
 
         return new_mem;