[dpdk-dev,v1] eal: fix negative value incorrectly being used defect
Commit Message
In eal_intr_proc_rxtx_intr, negative value may be used as argument to a function expecting a positive value. If 'read' returns EAGAIN as example, the bytes_read updates to a negative value which continue be passed as argument for the next 'read'.
Coverity issue: 107115
927 do {
3. negative_return_fn: Function read(fd, &buf, bytes_read) returns a negative number.
4. var_assign: Assigning: signed variable bytes_read = read.
CID 107115 (#1 of 1): Argument cannot be negative
(NEGATIVE_RETURNS)9. negative_returns: bytes_read is passed to a parameter
that cannot be negative.
928 bytes_read = read(fd, &buf, bytes_read);
Fixes: c9f3ec1a0f3f ("eal/linux: add Rx interrupt control function")
Signed-off-by: Cunming Liang <cunming.liang@intel.com>
---
lib/librte_eal/linuxapp/eal/eal_interrupts.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
Comments
> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Cunming Liang
> Sent: Friday, December 11, 2015 1:49 AM
> To: dev@dpdk.org
> Subject: [dpdk-dev] [PATCH v1] eal: fix negative value incorrectly being
> used defect
>
> In eal_intr_proc_rxtx_intr, negative value may be used as argument to a
> function expecting a positive value. If 'read' returns EAGAIN as example,
> the bytes_read updates to a negative value which continue be passed as
> argument for the next 'read'.
>
> Coverity issue: 107115
>
> 927 do {
> 3. negative_return_fn: Function read(fd, &buf, bytes_read) returns a
> negative number.
> 4. var_assign: Assigning: signed variable bytes_read = read.
> CID 107115 (#1 of 1): Argument cannot be negative
> (NEGATIVE_RETURNS)9. negative_returns: bytes_read is passed to a
> parameter
> that cannot be negative.
> 928 bytes_read = read(fd, &buf, bytes_read);
>
> Fixes: c9f3ec1a0f3f ("eal/linux: add Rx interrupt control function")
>
> Signed-off-by: Cunming Liang <cunming.liang@intel.com>
Acked-by: John McNamara <john.mcnamara@intel.com>
Hello Cunming,
On Fri, Dec 11, 2015 at 2:48 AM, Cunming Liang <cunming.liang@intel.com>
wrote:
> In eal_intr_proc_rxtx_intr, negative value may be used as argument to a
> function expecting a positive value. If 'read' returns EAGAIN as example,
> the bytes_read updates to a negative value which continue be passed as
> argument for the next 'read'.
>
> Coverity issue: 107115
>
> 927 do {
> 3. negative_return_fn: Function read(fd, &buf, bytes_read) returns a
> negative number.
> 4. var_assign: Assigning: signed variable bytes_read = read.
> CID 107115 (#1 of 1): Argument cannot be negative
> (NEGATIVE_RETURNS)9. negative_returns: bytes_read is passed to a
> parameter
> that cannot be negative.
> 928 bytes_read = read(fd, &buf, bytes_read);
>
> Fixes: c9f3ec1a0f3f ("eal/linux: add Rx interrupt control function")
>
> Signed-off-by: Cunming Liang <cunming.liang@intel.com>
>
Acked-by: David Marchand <david.marchand@6wind.com>
Thanks.
2015-12-11 15:54, David Marchand:
> Hello Cunming,
>
> On Fri, Dec 11, 2015 at 2:48 AM, Cunming Liang <cunming.liang@intel.com>
> wrote:
>
> > In eal_intr_proc_rxtx_intr, negative value may be used as argument to a
> > function expecting a positive value. If 'read' returns EAGAIN as example,
> > the bytes_read updates to a negative value which continue be passed as
> > argument for the next 'read'.
> >
> > Coverity issue: 107115
> >
> > 927 do {
> > 3. negative_return_fn: Function read(fd, &buf, bytes_read) returns a
> > negative number.
> > 4. var_assign: Assigning: signed variable bytes_read = read.
> > CID 107115 (#1 of 1): Argument cannot be negative
> > (NEGATIVE_RETURNS)9. negative_returns: bytes_read is passed to a
> > parameter
> > that cannot be negative.
> > 928 bytes_read = read(fd, &buf, bytes_read);
> >
> > Fixes: c9f3ec1a0f3f ("eal/linux: add Rx interrupt control function")
> >
> > Signed-off-by: Cunming Liang <cunming.liang@intel.com>
> >
>
> Acked-by: David Marchand <david.marchand@6wind.com>
Applied, thanks
@@ -901,6 +901,7 @@ eal_intr_proc_rxtx_intr(int fd, const struct rte_intr_handle *intr_handle)
{
union rte_intr_read_buffer buf;
int bytes_read = 1;
+ int nbytes;
switch (intr_handle->type) {
case RTE_INTR_HANDLE_UIO:
@@ -925,15 +926,15 @@ eal_intr_proc_rxtx_intr(int fd, const struct rte_intr_handle *intr_handle)
* for epoll_wait.
*/
do {
- bytes_read = read(fd, &buf, bytes_read);
- if (bytes_read < 0) {
+ nbytes = read(fd, &buf, bytes_read);
+ if (nbytes < 0) {
if (errno == EINTR || errno == EWOULDBLOCK ||
errno == EAGAIN)
continue;
RTE_LOG(ERR, EAL,
"Error reading from fd %d: %s\n",
fd, strerror(errno));
- } else if (bytes_read == 0)
+ } else if (nbytes == 0)
RTE_LOG(ERR, EAL, "Read nothing from fd %d\n", fd);
return;
} while (1);