[v2,1/7] malloc: Add check for top size corruption.

Message ID 1510068430-27816-2-git-send-email-pistukem@gmail.com
State New
Headers show
Series
  • Additional integrity checks for the malloc
Related show

Commit Message

Istvan Kurucsai Nov. 7, 2017, 3:27 p.m.
Ensure that the size of top is below av->system_mem.

    * malloc/malloc.c (_int_malloc): Check top size.
---
 malloc/malloc.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Andreas Schwab Nov. 7, 2017, 3:53 p.m. | #1
On Nov 07 2017, Istvan Kurucsai <pistukem@gmail.com> wrote:

> diff --git a/malloc/malloc.c b/malloc/malloc.c
> index f94d51c..4a30c42 100644
> --- a/malloc/malloc.c
> +++ b/malloc/malloc.c
> @@ -4078,6 +4078,10 @@ _int_malloc (mstate av, size_t bytes)
>  
>        if ((unsigned long) (size) >= (unsigned long) (nb + MINSIZE))
>          {
> +          if (__glibc_unlikely ((unsigned long) (size) > 
> +                                (unsigned long) (av->system_mem)))

Line break before operator, not after.  Redundant parens.

> +            malloc_printerr("malloc(): corrupted top chunk");

Space before paren.

Andreas.

Patch

diff --git a/malloc/malloc.c b/malloc/malloc.c
index f94d51c..4a30c42 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -4078,6 +4078,10 @@  _int_malloc (mstate av, size_t bytes)
 
       if ((unsigned long) (size) >= (unsigned long) (nb + MINSIZE))
         {
+          if (__glibc_unlikely ((unsigned long) (size) > 
+                                (unsigned long) (av->system_mem)))
+            malloc_printerr("malloc(): corrupted top chunk");
+
           remainder_size = size - nb;
           remainder = chunk_at_offset (victim, nb);
           av->top = remainder;