[dpdk-dev] [PATCH] mem: fix the alloc size roundup overflow

[dpdk-dev] [PATCH] mem: fix the alloc size roundup overflow

[Bing Zhao]

The size checking is done in the caller. The size parameter is an
unsigned (64b wide) right now, so the comparison with zero should be
enough in most cases. But it won't help in the following case.
If the allocating request input a huge number by mistake, e.g., some
overflow after the calculation (especially subtraction), the checking
in the caller will succeed since it is not zero. Indeed, there is not
enough space in the system to support such huge memory allocation.
Usually it will return failure in the following code. But if the
input size is just a little smaller than the UINT64_MAX, like -2 in
signed type.
The roundup will cause an overflow and then "reset" the size to 0,
and then only a header (128B now) with zero length will be returned.
The following will be the previous allocation header.
It should be OK in most cases if the application won't access the
memory body. Or else, some critical issue will be caused and not easy
to debug. So this issue should be prevented at the beginning, like
other big size failure, NULL pointer should be returned also.

Fixes: fdf20fa7bee9 ("add prefix to cache line macros")
Cc: sergio.gonzalez.monroy@intel.com
Cc: stable@dpdk.org

Signed-off-by: Bing Zhao <bingz@mellanox.com>
---
 lib/librte_eal/common/malloc_heap.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/librte_eal/common/malloc_heap.c b/lib/librte_eal/common/malloc_heap.c
index 842eb9d..bd50656 100644
--- a/lib/librte_eal/common/malloc_heap.c
+++ b/lib/librte_eal/common/malloc_heap.c
@@ -241,6 +241,9 @@
 	size = RTE_CACHE_LINE_ROUNDUP(size);
 	align = RTE_CACHE_LINE_ROUNDUP(align);
 
+	/* roundup might cause an overflow */
+	if (size == 0)
+		return NULL;
 	elem = find_suitable_element(heap, size, flags, align, bound, contig);
 	if (elem != NULL) {
 		elem = malloc_elem_alloc(elem, size, align, bound, contig);
-- 
1.8.3.1

Re: [dpdk-dev] [PATCH] mem: fix the alloc size roundup overflow

[Burakov, Anatoly]

On 07-Apr-20 11:46 AM, Bing Zhao wrote:
> The size checking is done in the caller. The size parameter is an
> unsigned (64b wide) right now, so the comparison with zero should be
> enough in most cases. But it won't help in the following case.
> If the allocating request input a huge number by mistake, e.g., some
> overflow after the calculation (especially subtraction), the checking
> in the caller will succeed since it is not zero. Indeed, there is not
> enough space in the system to support such huge memory allocation.
> Usually it will return failure in the following code. But if the
> input size is just a little smaller than the UINT64_MAX, like -2 in
> signed type.
> The roundup will cause an overflow and then "reset" the size to 0,
> and then only a header (128B now) with zero length will be returned.
> The following will be the previous allocation header.
> It should be OK in most cases if the application won't access the
> memory body. Or else, some critical issue will be caused and not easy
> to debug. So this issue should be prevented at the beginning, like
> other big size failure, NULL pointer should be returned also.
> 
> Fixes: fdf20fa7bee9 ("add prefix to cache line macros")
> Cc: sergio.gonzalez.monroy@intel.com
> Cc: stable@dpdk.org
> 
> Signed-off-by: Bing Zhao <bingz@mellanox.com>
> ---
>   lib/librte_eal/common/malloc_heap.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/lib/librte_eal/common/malloc_heap.c b/lib/librte_eal/common/malloc_heap.c
> index 842eb9d..bd50656 100644
> --- a/lib/librte_eal/common/malloc_heap.c
> +++ b/lib/librte_eal/common/malloc_heap.c
> @@ -241,6 +241,9 @@
>   	size = RTE_CACHE_LINE_ROUNDUP(size);
>   	align = RTE_CACHE_LINE_ROUNDUP(align);
>   
> +	/* roundup might cause an overflow */
> +	if (size == 0)
> +		return NULL;
>   	elem = find_suitable_element(heap, size, flags, align, bound, contig);
>   	if (elem != NULL) {
>   		elem = malloc_elem_alloc(elem, size, align, bound, contig);
> 

Can we add a unit test for this in malloc_autotest?

Otherwise,

Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>

-- 
Thanks,
Anatoly

Re: [dpdk-dev] [PATCH] mem: fix the alloc size roundup overflow

[Bing Zhao]

> -----Original Message-----
> From: Burakov, Anatoly <anatoly.burakov@intel.com>
> Sent: Monday, April 20, 2020 7:40 PM
> To: Bing Zhao <bingz@mellanox.com>
> Cc: dev@dpdk.org; sergio.gonzalez.monroy@intel.com;
> stable@dpdk.org
> Subject: Re: [PATCH] mem: fix the alloc size roundup overflow
> 
> On 07-Apr-20 11:46 AM, Bing Zhao wrote:
> > The size checking is done in the caller. The size parameter is an
> > unsigned (64b wide) right now, so the comparison with zero should
> be
> > enough in most cases. But it won't help in the following case.
> > If the allocating request input a huge number by mistake, e.g., some
> > overflow after the calculation (especially subtraction), the checking
> > in the caller will succeed since it is not zero. Indeed, there is not
> > enough space in the system to support such huge memory allocation.
> > Usually it will return failure in the following code. But if the input
> > size is just a little smaller than the UINT64_MAX, like -2 in signed
> > type.
> > The roundup will cause an overflow and then "reset" the size to 0,
> and
> > then only a header (128B now) with zero length will be returned.
> > The following will be the previous allocation header.
> > It should be OK in most cases if the application won't access the
> > memory body. Or else, some critical issue will be caused and not easy
> > to debug. So this issue should be prevented at the beginning, like
> > other big size failure, NULL pointer should be returned also.
> >
> > Fixes: fdf20fa7bee9 ("add prefix to cache line macros")
> > Cc: sergio.gonzalez.monroy@intel.com
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Bing Zhao <bingz@mellanox.com>
> > ---
> >   lib/librte_eal/common/malloc_heap.c | 3 +++
> >   1 file changed, 3 insertions(+)
> >
> > diff --git a/lib/librte_eal/common/malloc_heap.c
> > b/lib/librte_eal/common/malloc_heap.c
> > index 842eb9d..bd50656 100644
> > --- a/lib/librte_eal/common/malloc_heap.c
> > +++ b/lib/librte_eal/common/malloc_heap.c
> > @@ -241,6 +241,9 @@
> >   	size = RTE_CACHE_LINE_ROUNDUP(size);
> >   	align = RTE_CACHE_LINE_ROUNDUP(align);
> >
> > +	/* roundup might cause an overflow */
> > +	if (size == 0)
> > +		return NULL;
> >   	elem = find_suitable_element(heap, size, flags, align, bound,
> contig);
> >   	if (elem != NULL) {
> >   		elem = malloc_elem_alloc(elem, size, align, bound,
> contig);
> >
> 
> Can we add a unit test for this in malloc_autotest?
> 
> Otherwise,
> 
> Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>
> 

Thanks, Burakov. I can try to add one case in the unit for this.

> --
> Thanks,
> Anatoly

Re: [dpdk-dev] [dpdk-stable] [PATCH] mem: fix the alloc size roundup overflow

[Thomas Monjalon]

21/04/2020 05:18, Bing Zhao:
> From: Burakov, Anatoly <anatoly.burakov@intel.com>
> > Can we add a unit test for this in malloc_autotest?
> > 
> > Otherwise,
> > 
> > Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>
> 
> Thanks, Burakov. I can try to add one case in the unit for this.

Any update about writing an unit test?

[dpdk-dev] [PATCH v2] mem: fix the alloc size roundup overflow

[Bing Zhao]

The size checking is done in the caller. The size parameter is an
unsigned (64b wide) right now, so the comparison with zero should be
enough in most cases. But it won't help in the following case.
If the allocating request input a huge number by mistake, e.g., some
overflow after the calculation (especially subtraction), the checking
in the caller will succeed since it is not zero. Indeed, there is not
enough space in the system to support such huge memory allocation.
Usually it will return failure in the following code. But if the
input size is just a little smaller than the UINT64_MAX, like -2 in
signed type.
The roundup will cause an overflow and then "reset" the size to 0,
and then only a header (128B now) with zero length will be returned.
The following will be the previous allocation header.
It should be OK in most cases if the application won't access the
memory body. Or else, some critical issue will be caused and not easy
to debug. So this issue should be prevented at the beginning, like
other big size failure, NULL pointer should be returned also.

Fixes: fdf20fa7bee9 ("add prefix to cache line macros")
Cc: sergio.gonzalez.monroy@intel.com
Cc: stable@dpdk.org

Signed-off-by: Bing Zhao <bingz@mellanox.com>
---
 app/test/test_malloc.c              | 12 ++++++++++++
 lib/librte_eal/common/malloc_heap.c |  3 +++
 2 files changed, 15 insertions(+)

diff --git a/app/test/test_malloc.c b/app/test/test_malloc.c
index 40a2f50..a96c060 100644
--- a/app/test/test_malloc.c
+++ b/app/test/test_malloc.c
@@ -846,6 +846,18 @@
 	if (bad_ptr != NULL)
 		goto err_return;
 
+	/* rte_malloc expected to return null with size will cause overflow */
+	align = RTE_CACHE_LINE_SIZE;
+	size = (size_t)-8;
+
+	bad_ptr = rte_malloc(type, size, align);
+	if (bad_ptr != NULL)
+		goto err_return;
+
+	bad_ptr = rte_realloc(NULL, size, align);
+        if (bad_ptr != NULL)
+                goto err_return;
+
 	return 0;
 
 err_return:
diff --git a/lib/librte_eal/common/malloc_heap.c b/lib/librte_eal/common/malloc_heap.c
index 842eb9d..bd50656 100644
--- a/lib/librte_eal/common/malloc_heap.c
+++ b/lib/librte_eal/common/malloc_heap.c
@@ -241,6 +241,9 @@
 	size = RTE_CACHE_LINE_ROUNDUP(size);
 	align = RTE_CACHE_LINE_ROUNDUP(align);
 
+	/* roundup might cause an overflow */
+	if (size == 0)
+		return NULL;
 	elem = find_suitable_element(heap, size, flags, align, bound, contig);
 	if (elem != NULL) {
 		elem = malloc_elem_alloc(elem, size, align, bound, contig);
-- 
1.8.3.1

[dpdk-dev] [PATCH v2] mem: fix the alloc size roundup overflow

[Bing Zhao]

The size checking is done in the caller. The size parameter is an
unsigned (64b wide) right now, so the comparison with zero should be
enough in most cases. But it won't help in the following case.
If the allocating request input a huge number by mistake, e.g., some
overflow after the calculation (especially subtraction), the checking
in the caller will succeed since it is not zero. Indeed, there is not
enough space in the system to support such huge memory allocation.
Usually it will return failure in the following code. But if the
input size is just a little smaller than the UINT64_MAX, like -2 in
signed type.
The roundup will cause an overflow and then "reset" the size to 0,
and then only a header (128B now) with zero length will be returned.
The following will be the previous allocation header.
It should be OK in most cases if the application won't access the
memory body. Or else, some critical issue will be caused and not easy
to debug. So this issue should be prevented at the beginning, like
other big size failure, NULL pointer should be returned also.

Fixes: fdf20fa7bee9 ("add prefix to cache line macros")
Cc: sergio.gonzalez.monroy@intel.com
Cc: stable@dpdk.org

Signed-off-by: Bing Zhao <bingz@mellanox.com>
---
v2: add unit test for this case
---
 app/test/test_malloc.c              | 12 ++++++++++++
 lib/librte_eal/common/malloc_heap.c |  3 +++
 2 files changed, 15 insertions(+)

diff --git a/app/test/test_malloc.c b/app/test/test_malloc.c
index 40a2f50..a96c060 100644
--- a/app/test/test_malloc.c
+++ b/app/test/test_malloc.c
@@ -846,6 +846,18 @@
 	if (bad_ptr != NULL)
 		goto err_return;
 
+	/* rte_malloc expected to return null with size will cause overflow */
+	align = RTE_CACHE_LINE_SIZE;
+	size = (size_t)-8;
+
+	bad_ptr = rte_malloc(type, size, align);
+	if (bad_ptr != NULL)
+		goto err_return;
+
+	bad_ptr = rte_realloc(NULL, size, align);
+        if (bad_ptr != NULL)
+                goto err_return;
+
 	return 0;
 
 err_return:
diff --git a/lib/librte_eal/common/malloc_heap.c b/lib/librte_eal/common/malloc_heap.c
index 842eb9d..bd50656 100644
--- a/lib/librte_eal/common/malloc_heap.c
+++ b/lib/librte_eal/common/malloc_heap.c
@@ -241,6 +241,9 @@
 	size = RTE_CACHE_LINE_ROUNDUP(size);
 	align = RTE_CACHE_LINE_ROUNDUP(align);
 
+	/* roundup might cause an overflow */
+	if (size == 0)
+		return NULL;
 	elem = find_suitable_element(heap, size, flags, align, bound, contig);
 	if (elem != NULL) {
 		elem = malloc_elem_alloc(elem, size, align, bound, contig);
-- 
1.8.3.1

[dpdk-dev] [PATCH v3] mem: fix the alloc size roundup overflow

[Bing Zhao]

The size checking is done in the caller. The size parameter is an
unsigned (64b wide) right now, so the comparison with zero should be
enough in most cases. But it won't help in the following case.
If the allocating request input a huge number by mistake, e.g., some
overflow after the calculation (especially subtraction), the checking
in the caller will succeed since it is not zero. Indeed, there is not
enough space in the system to support such huge memory allocation.
Usually it will return failure in the following code. But if the
input size is just a little smaller than the UINT64_MAX, like -2 in
signed type.
The roundup will cause an overflow and then "reset" the size to 0,
and then only a header (128B now) with zero length will be returned.
The following will be the previous allocation header.
It should be OK in most cases if the application won't access the
memory body. Or else, some critical issue will be caused and not easy
to debug. So this issue should be prevented at the beginning, like
other big size failure, NULL pointer should be returned also.

Fixes: fdf20fa7bee9 ("add prefix to cache line macros")
Cc: sergio.gonzalez.monroy@intel.com
Cc: stable@dpdk.org

Signed-off-by: Bing Zhao <bingz@mellanox.com>
---
v2: add unit test for this case
v3: fix the code style by using tab
---
 app/test/test_malloc.c              | 12 ++++++++++++
 lib/librte_eal/common/malloc_heap.c |  3 +++
 2 files changed, 15 insertions(+)

diff --git a/app/test/test_malloc.c b/app/test/test_malloc.c
index 40a2f50..71b3cfd 100644
--- a/app/test/test_malloc.c
+++ b/app/test/test_malloc.c
@@ -846,6 +846,18 @@
 	if (bad_ptr != NULL)
 		goto err_return;
 
+	/* rte_malloc expected to return null with size will cause overflow */
+	align = RTE_CACHE_LINE_SIZE;
+	size = (size_t)-8;
+
+	bad_ptr = rte_malloc(type, size, align);
+	if (bad_ptr != NULL)
+		goto err_return;
+
+	bad_ptr = rte_realloc(NULL, size, align);
+	if (bad_ptr != NULL)
+		goto err_return;
+
 	return 0;
 
 err_return:
diff --git a/lib/librte_eal/common/malloc_heap.c b/lib/librte_eal/common/malloc_heap.c
index 842eb9d..bd50656 100644
--- a/lib/librte_eal/common/malloc_heap.c
+++ b/lib/librte_eal/common/malloc_heap.c
@@ -241,6 +241,9 @@
 	size = RTE_CACHE_LINE_ROUNDUP(size);
 	align = RTE_CACHE_LINE_ROUNDUP(align);
 
+	/* roundup might cause an overflow */
+	if (size == 0)
+		return NULL;
 	elem = find_suitable_element(heap, size, flags, align, bound, contig);
 	if (elem != NULL) {
 		elem = malloc_elem_alloc(elem, size, align, bound, contig);
-- 
1.8.3.1

Re: [dpdk-dev] [PATCH v3] mem: fix the alloc size roundup overflow

[David Marchand]

On Thu, May 7, 2020 at 10:03 AM Bing Zhao <bingz@mellanox.com> wrote:
>
> The size checking is done in the caller. The size parameter is an
> unsigned (64b wide) right now, so the comparison with zero should be
> enough in most cases. But it won't help in the following case.
> If the allocating request input a huge number by mistake, e.g., some
> overflow after the calculation (especially subtraction), the checking
> in the caller will succeed since it is not zero. Indeed, there is not
> enough space in the system to support such huge memory allocation.
> Usually it will return failure in the following code. But if the
> input size is just a little smaller than the UINT64_MAX, like -2 in
> signed type.
> The roundup will cause an overflow and then "reset" the size to 0,
> and then only a header (128B now) with zero length will be returned.
> The following will be the previous allocation header.
> It should be OK in most cases if the application won't access the
> memory body. Or else, some critical issue will be caused and not easy
> to debug. So this issue should be prevented at the beginning, like
> other big size failure, NULL pointer should be returned also.
>
> Fixes: fdf20fa7bee9 ("add prefix to cache line macros")
> Cc: stable@dpdk.org
>
> Signed-off-by: Bing Zhao <bingz@mellanox.com>

Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>

Applied, thanks.


-- 
David Marchand

Re: [dpdk-dev] [PATCH v2] mem: fix the alloc size roundup overflow

[Burakov, Anatoly]

On 07-May-20 8:41 AM, Bing Zhao wrote:
> The size checking is done in the caller. The size parameter is an
> unsigned (64b wide) right now, so the comparison with zero should be
> enough in most cases. But it won't help in the following case.
> If the allocating request input a huge number by mistake, e.g., some
> overflow after the calculation (especially subtraction), the checking
> in the caller will succeed since it is not zero. Indeed, there is not
> enough space in the system to support such huge memory allocation.
> Usually it will return failure in the following code. But if the
> input size is just a little smaller than the UINT64_MAX, like -2 in
> signed type.
> The roundup will cause an overflow and then "reset" the size to 0,
> and then only a header (128B now) with zero length will be returned.
> The following will be the previous allocation header.
> It should be OK in most cases if the application won't access the
> memory body. Or else, some critical issue will be caused and not easy
> to debug. So this issue should be prevented at the beginning, like
> other big size failure, NULL pointer should be returned also.
> 
> Fixes: fdf20fa7bee9 ("add prefix to cache line macros")
> Cc: sergio.gonzalez.monroy@intel.com
> Cc: stable@dpdk.org
> 
> Signed-off-by: Bing Zhao <bingz@mellanox.com>
> ---
> v2: add unit test for this case
> ---
>   app/test/test_malloc.c              | 12 ++++++++++++
>   lib/librte_eal/common/malloc_heap.c |  3 +++
>   2 files changed, 15 insertions(+)
> 
> diff --git a/app/test/test_malloc.c b/app/test/test_malloc.c
> index 40a2f50..a96c060 100644
> --- a/app/test/test_malloc.c
> +++ b/app/test/test_malloc.c
> @@ -846,6 +846,18 @@
>   	if (bad_ptr != NULL)
>   		goto err_return;
>   
> +	/* rte_malloc expected to return null with size will cause overflow */
> +	align = RTE_CACHE_LINE_SIZE;
> +	size = (size_t)-8;
> +
> +	bad_ptr = rte_malloc(type, size, align);
> +	if (bad_ptr != NULL)
> +		goto err_return;
> +
> +	bad_ptr = rte_realloc(NULL, size, align);
> +        if (bad_ptr != NULL)
> +                goto err_return;

You're mixing space and tabs as indentation here.

Otherwise,

Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>

> +
>   	return 0;
>   
>   err_return:
> diff --git a/lib/librte_eal/common/malloc_heap.c b/lib/librte_eal/common/malloc_heap.c
> index 842eb9d..bd50656 100644
> --- a/lib/librte_eal/common/malloc_heap.c
> +++ b/lib/librte_eal/common/malloc_heap.c
> @@ -241,6 +241,9 @@
>   	size = RTE_CACHE_LINE_ROUNDUP(size);
>   	align = RTE_CACHE_LINE_ROUNDUP(align);
>   
> +	/* roundup might cause an overflow */
> +	if (size == 0)
> +		return NULL;
>   	elem = find_suitable_element(heap, size, flags, align, bound, contig);
>   	if (elem != NULL) {
>   		elem = malloc_elem_alloc(elem, size, align, bound, contig);
> 


-- 
Thanks,
Anatoly

Re: [dpdk-dev] [dpdk-stable] [PATCH v2] mem: fix the alloc size roundup overflow

[David Marchand]

On Thu, May 7, 2020 at 1:55 PM Burakov, Anatoly
<anatoly.burakov@intel.com> wrote:
>
> On 07-May-20 8:41 AM, Bing Zhao wrote:
> > The size checking is done in the caller. The size parameter is an
> > unsigned (64b wide) right now, so the comparison with zero should be
> > enough in most cases. But it won't help in the following case.
> > If the allocating request input a huge number by mistake, e.g., some
> > overflow after the calculation (especially subtraction), the checking
> > in the caller will succeed since it is not zero. Indeed, there is not
> > enough space in the system to support such huge memory allocation.
> > Usually it will return failure in the following code. But if the
> > input size is just a little smaller than the UINT64_MAX, like -2 in
> > signed type.
> > The roundup will cause an overflow and then "reset" the size to 0,
> > and then only a header (128B now) with zero length will be returned.
> > The following will be the previous allocation header.
> > It should be OK in most cases if the application won't access the
> > memory body. Or else, some critical issue will be caused and not easy
> > to debug. So this issue should be prevented at the beginning, like
> > other big size failure, NULL pointer should be returned also.
> >
> > Fixes: fdf20fa7bee9 ("add prefix to cache line macros")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Bing Zhao <bingz@mellanox.com>
> > ---
> > v2: add unit test for this case
> > ---
> >   app/test/test_malloc.c              | 12 ++++++++++++
> >   lib/librte_eal/common/malloc_heap.c |  3 +++
> >   2 files changed, 15 insertions(+)
> >
> > diff --git a/app/test/test_malloc.c b/app/test/test_malloc.c
> > index 40a2f50..a96c060 100644
> > --- a/app/test/test_malloc.c
> > +++ b/app/test/test_malloc.c
> > @@ -846,6 +846,18 @@
> >       if (bad_ptr != NULL)
> >               goto err_return;
> >
> > +     /* rte_malloc expected to return null with size will cause overflow */
> > +     align = RTE_CACHE_LINE_SIZE;
> > +     size = (size_t)-8;
> > +
> > +     bad_ptr = rte_malloc(type, size, align);
> > +     if (bad_ptr != NULL)
> > +             goto err_return;
> > +
> > +     bad_ptr = rte_realloc(NULL, size, align);
> > +        if (bad_ptr != NULL)
> > +                goto err_return;
>
> You're mixing space and tabs as indentation here.

Will fix while applying.

>
> Otherwise,
>
> Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>

You acked the v1, so I will go with it.
Thanks for the work Bing, Anatoly.


-- 
David Marchand

Re: [dpdk-dev] [dpdk-stable] [PATCH v2] mem: fix the alloc size roundup overflow

[Bing Zhao]

Hi David,
I've changed the space into tabs in v3 and suppressed this one.

Thanks a lot

BR. Bing

> -----Original Message-----
> From: David Marchand <david.marchand@redhat.com>
> Sent: Thursday, May 7, 2020 8:12 PM
> To: Burakov, Anatoly <anatoly.burakov@intel.com>; Bing Zhao
> <bingz@mellanox.com>
> Cc: Thomas Monjalon <thomas@monjalon.net>; dev <dev@dpdk.org>;
> dpdk stable <stable@dpdk.org>; sergio.gonzalez.monroy@intel.com
> Subject: Re: [dpdk-stable] [PATCH v2] mem: fix the alloc size roundup
> overflow
> 
> On Thu, May 7, 2020 at 1:55 PM Burakov, Anatoly
> <anatoly.burakov@intel.com> wrote:
> >
> > On 07-May-20 8:41 AM, Bing Zhao wrote:
> > > The size checking is done in the caller. The size parameter is an
> > > unsigned (64b wide) right now, so the comparison with zero should
> be
> > > enough in most cases. But it won't help in the following case.
> > > If the allocating request input a huge number by mistake, e.g.,
> some
> > > overflow after the calculation (especially subtraction), the
> > > checking in the caller will succeed since it is not zero. Indeed,
> > > there is not enough space in the system to support such huge
> memory allocation.
> > > Usually it will return failure in the following code. But if the
> > > input size is just a little smaller than the UINT64_MAX, like -2 in
> > > signed type.
> > > The roundup will cause an overflow and then "reset" the size to 0,
> > > and then only a header (128B now) with zero length will be
> returned.
> > > The following will be the previous allocation header.
> > > It should be OK in most cases if the application won't access the
> > > memory body. Or else, some critical issue will be caused and not
> > > easy to debug. So this issue should be prevented at the beginning,
> > > like other big size failure, NULL pointer should be returned also.
> > >
> > > Fixes: fdf20fa7bee9 ("add prefix to cache line macros")
> > > Cc: stable@dpdk.org
> > >
> > > Signed-off-by: Bing Zhao <bingz@mellanox.com>
> > > ---
> > > v2: add unit test for this case
> > > ---
> > >   app/test/test_malloc.c              | 12 ++++++++++++
> > >   lib/librte_eal/common/malloc_heap.c |  3 +++
> > >   2 files changed, 15 insertions(+)
> > >
> > > diff --git a/app/test/test_malloc.c b/app/test/test_malloc.c index
> > > 40a2f50..a96c060 100644
> > > --- a/app/test/test_malloc.c
> > > +++ b/app/test/test_malloc.c
> > > @@ -846,6 +846,18 @@
> > >       if (bad_ptr != NULL)
> > >               goto err_return;
> > >
> > > +     /* rte_malloc expected to return null with size will cause
> overflow */
> > > +     align = RTE_CACHE_LINE_SIZE;
> > > +     size = (size_t)-8;
> > > +
> > > +     bad_ptr = rte_malloc(type, size, align);
> > > +     if (bad_ptr != NULL)
> > > +             goto err_return;
> > > +
> > > +     bad_ptr = rte_realloc(NULL, size, align);
> > > +        if (bad_ptr != NULL)
> > > +                goto err_return;
> >
> > You're mixing space and tabs as indentation here.
> 
> Will fix while applying.
> 
> >
> > Otherwise,
> >
> > Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>
> 
> You acked the v1, so I will go with it.
> Thanks for the work Bing, Anatoly.
> 
> 
> --
> David Marchand

Re: [dpdk-dev] [dpdk-stable] [PATCH v2] mem: fix the alloc size roundup overflow

[David Marchand]

On Thu, May 7, 2020 at 2:16 PM Bing Zhao <bingz@mellanox.com> wrote:
>
> Hi David,
> I've changed the space into tabs in v3 and suppressed this one.

Ok, I would have noticed anyway :-)
Thanks.


-- 
David Marchand