[dpdk-dev] [PATCH] eal: fix check number of bytes from read function

[Sergio Gonzalez Monroy]

On 20/07/2016 15:24, Michal Jastrzebski wrote:
> In rte_mem_virt2phy: Value returned from a function and indicating the
> number of bytes was ignored. This could cause a wrong pfn (page frame
> number) mask read from pagemap file.
> When read returns less than the number of sizeof(uint64_t) bytes,
> function rte_mem_virt2phy returns error.
>
> Coverity issue: 13212
> Fixes: 40b966a211ab ("ivshmem: library changes for mmaping using
> ivshmem").
>
> Signed-off-by: Michal Jastrzebski <michalx.k.jastrzebski at intel.com>
> ---
>   lib/librte_eal/linuxapp/eal/eal_memory.c |   12 ++++++++++--
>   1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
> index 42a29fa..05769fb 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_memory.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
> @@ -158,7 +158,7 @@ rte_mem_lock_page(const void *virt)
>   phys_addr_t
>   rte_mem_virt2phy(const void *virtaddr)
>   {
> -	int fd;
> +	int fd, retval;
>   	uint64_t page, physaddr;
>   	unsigned long virt_pfn;
>   	int page_size;
> @@ -209,11 +209,19 @@ rte_mem_virt2phy(const void *virtaddr)
>   		close(fd);
>   		return RTE_BAD_PHYS_ADDR;
>   	}
> -	if (read(fd, &page, sizeof(uint64_t)) < 0) {
> +
> +	retval = read(fd, &page, sizeof(uint64_t));
> +	if (retval < 0) {
>   		RTE_LOG(ERR, EAL, "%s(): cannot read /proc/self/pagemap: %s\n",
>   				__func__, strerror(errno));
>   		close(fd);
>   		return RTE_BAD_PHYS_ADDR;
> +	}	else if (retval >= 0 && retval < (int)sizeof(uint64_t))	{

Just a couple of nits, retval >= 0 it's already implicit, no need to do 
that check.

> +		RTE_LOG(ERR, EAL, "%s(): read %d bytes from /proc/self/pagemap "
> +				"but expected %d: %s\n",
> +				__func__, retval, (int)sizeof(uint64_t), strerror(errno));
> +		close(fd);

Another nit, we could just close(fd) right after read, regardless of 
read being success or error as
we close(fd) also on success just before exiting the function.

Other than that:

Acked-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy at intel.com>

> +		return RTE_BAD_PHYS_ADDR;
>   	}
>   
>   	/*