[dpdk-dev] [PATCH] mem: fix possible memzone integer overflow

[Thomas Monjalon]

2016-06-14 19:07, Sergio Gonzalez Monroy:
> It is possible to get an integer overflow if we try to reserve a memzone
> with len = 0 (meaning the maximum contiguous space available) and the
> maximum available elem size is less than (MALLOC_ELEM_OVERHEAD + align).
> 
> Issue reported by Coverity:
> 
>>>> 10. overflow: Subtract operation overflows on operands len and
>>>> 64UL.
>>>> CID 107111 (#1 of 1): Overflowed return value (INTEGER_OVERFLOW)
>>>> 11. overflow_sink: Overflowed or truncated value (or a value
>>>> computed from an overflowed or truncated value)
>>>> len - 64UL - align used as return value.
>122 return len - MALLOC_ELEM_OVERHEAD - align;
> 
> Fixes: fafcc11985a2 ("mem: rework memzone to be allocated by malloc")
> 
> Signed-off-by: Sergio Gonzalez Monroy 

Applied, thanks

[dpdk-dev] [PATCH] mem: fix possible memzone integer overflow

[Sergio Gonzalez Monroy]

It is possible to get an integer overflow if we try to reserve a memzone
with len = 0 (meaning the maximum contiguous space available) and the
maximum available elem size is less than (MALLOC_ELEM_OVERHEAD + align).

Issue reported by Coverity:

   >>> 10. overflow: Subtract operation overflows on operands len and
   >>> 64UL.
   >>> CID 107111 (#1 of 1): Overflowed return value (INTEGER_OVERFLOW)
   >>> 11. overflow_sink: Overflowed or truncated value (or a value
   >>> computed from an overflowed or truncated value)
   >>> len - 64UL - align used as return value.
   122 return len - MALLOC_ELEM_OVERHEAD - align;

Fixes: fafcc11985a2 ("mem: rework memzone to be allocated by malloc")

Signed-off-by: Sergio Gonzalez Monroy 
---
 lib/librte_eal/common/eal_common_memzone.c | 10 +-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/lib/librte_eal/common/eal_common_memzone.c 
b/lib/librte_eal/common/eal_common_memzone.c
index 452679e..5d28341 100644
--- a/lib/librte_eal/common/eal_common_memzone.c
+++ b/lib/librte_eal/common/eal_common_memzone.c
@@ -119,6 +119,9 @@ find_heap_max_free_elem(int *s, unsigned align)
}
}

+   if (len < MALLOC_ELEM_OVERHEAD + align)
+   return 0;
+
return len - MALLOC_ELEM_OVERHEAD - align;
 }

@@ -197,8 +200,13 @@ memzone_reserve_aligned_thread_unsafe(const char *name, 
size_t len,
if (len == 0) {
if (bound != 0)
requested_len = bound;
-   else
+   else {
requested_len = find_heap_max_free_elem(_id, 
align);
+   if (requested_len == 0) {
+   rte_errno = ENOMEM;
+   return NULL;
+   }
+   }
}

if (socket_id == SOCKET_ID_ANY)
-- 
2.4.11