DPDK sanitizer seems cannot detect the overflow issue sometimes

DPDK sanitizer seems cannot detect the overflow issue sometimes

[halsey.pian]

Dear All,

I would try to detect the illegal memory access issues in my App based on DPDK, so I add some codes based on several overflow scenario to check if it is detected in DPDK standalone project.

It seems that DPDK santizer cannot find the overflow issue below,

I add some code into examples/helloworld/main.c as below,

char*p = (char*)rte_zmalloc(NULL, 9, 4096);

if(p != NULL)
{
	p = p + 32;
	*p = 'A‘  // should be overflow here
}

But there is no any sanitzer output after dpdk-helloworld exit.

BTW, DPDK sanitzer can detect the overflow below,


char*p = (char*)rte_zmalloc(NULL, 9, 4096);

if(p != NULL)
{
	p[9] = 'A‘  // can be detected
}

Unfortunately, DPDK cannot detect the overflow when update the code to below,
	p[32] = 'A' // cannot be detected


Version: DPDK 21.11.1
OS: Fedora 32
Build: meson setup -Dbuildtype=debug -Db_lundef=false -Db_sanitize=address -Dexamples=hellowowrld build

Is it a known issue? I am confused with this. 
Could you provide some info? Thanks.

Best Regards
Halsey Pian

Re: DPDK sanitizer seems cannot detect the overflow issue sometimes

[Stephen Hemminger]

On Wed, 29 Jun 2022 09:56:03 +0000
"halsey.pian@longsys.com" <halsey.pian@longsys.com> wrote:

> Dear All,
> 
> I would try to detect the illegal memory access issues in my App based on DPDK, so I add some codes based on several overflow scenario to check if it is detected in DPDK standalone project.
> 
> It seems that DPDK santizer cannot find the overflow issue below,
> 
> I add some code into examples/helloworld/main.c as below,
> 
> char*p = (char*)rte_zmalloc(NULL, 9, 4096);
> 
> if(p != NULL)
> {
> 	p = p + 32;
> 	*p = 'A‘  // should be overflow here
> }
> 
> But there is no any sanitzer output after dpdk-helloworld exit.
> 
> BTW, DPDK sanitzer can detect the overflow below,
> 
> 
> char*p = (char*)rte_zmalloc(NULL, 9, 4096);
> 
> if(p != NULL)
> {
> 	p[9] = 'A‘  // can be detected
> }
> 
> Unfortunately, DPDK cannot detect the overflow when update the code to below,
> 	p[32] = 'A' // cannot be detected
> 
> 
> Version: DPDK 21.11.1
> OS: Fedora 32
> Build: meson setup -Dbuildtype=debug -Db_lundef=false -Db_sanitize=address -Dexamples=hellowowrld build
> 
> Is it a known issue? I am confused with this. 
> Could you provide some info? Thanks.
> 
> Best Regards
> Halsey Pian

Sorry, it won't work.

There is some integration with Google Address Sanitizer (ASAN) but it does not
change the underlying algorithm of how memory is allocated with rte_malloc().

The way ASAN works for regular malloc is that it adds guard regions for each
allocation. That would be very difficult to do with DPDK rte_malloc() which
uses huge pages.

You are better off just using regular malloc in your application unless you
need to use hugepages.