* [PATCH] getipv4sourcefilter: Get rid of alloca
@ 2023-05-30 18:32 Joe Simmons-Talbott
2023-05-31 12:37 ` Adhemerval Zanella Netto
0 siblings, 1 reply; 3+ messages in thread
From: Joe Simmons-Talbott @ 2023-05-30 18:32 UTC (permalink / raw)
To: libc-alpha; +Cc: Joe Simmons-Talbott
Use a scratch_buffer rather than alloca to avoid potential stack
overflows.
---
sysdeps/unix/sysv/linux/getipv4sourcefilter.c | 24 ++++++-------------
1 file changed, 7 insertions(+), 17 deletions(-)
diff --git a/sysdeps/unix/sysv/linux/getipv4sourcefilter.c b/sysdeps/unix/sysv/linux/getipv4sourcefilter.c
index 8a367b1048..ce72becead 100644
--- a/sysdeps/unix/sysv/linux/getipv4sourcefilter.c
+++ b/sysdeps/unix/sysv/linux/getipv4sourcefilter.c
@@ -16,9 +16,9 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
-#include <alloca.h>
#include <errno.h>
#include <stdlib.h>
+#include <scratch_buffer.h>
#include <string.h>
#include <stdint.h>
#include <netinet/in.h>
@@ -33,17 +33,12 @@ getipv4sourcefilter (int s, struct in_addr interface, struct in_addr group,
/* We have to create an struct ip_msfilter object which we can pass
to the kernel. */
socklen_t needed = IP_MSFILTER_SIZE (*numsrc);
- int use_alloca = __libc_use_alloca (needed);
- struct ip_msfilter *imsf;
- if (use_alloca)
- imsf = (struct ip_msfilter *) alloca (needed);
- else
- {
- imsf = (struct ip_msfilter *) malloc (needed);
- if (imsf == NULL)
- return -1;
- }
+ struct scratch_buffer buf;
+ scratch_buffer_init (&buf);
+ if (!scratch_buffer_set_array_size (&buf, 1, needed))
+ return -1;
+ struct ip_msfilter *imsf = buf.data;
imsf->imsf_multiaddr = group;
imsf->imsf_interface = interface;
@@ -61,12 +56,7 @@ getipv4sourcefilter (int s, struct in_addr interface, struct in_addr group,
*numsrc = imsf->imsf_numsrc;
}
- if (! use_alloca)
- {
- int save_errno = errno;
- free (imsf);
- __set_errno (save_errno);
- }
+ scratch_buffer_free (&buf);
return result;
}
--
2.39.2
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] getipv4sourcefilter: Get rid of alloca
2023-05-30 18:32 [PATCH] getipv4sourcefilter: Get rid of alloca Joe Simmons-Talbott
@ 2023-05-31 12:37 ` Adhemerval Zanella Netto
2023-06-01 14:20 ` Joe Simmons-Talbott
0 siblings, 1 reply; 3+ messages in thread
From: Adhemerval Zanella Netto @ 2023-05-31 12:37 UTC (permalink / raw)
To: Joe Simmons-Talbott, libc-alpha
On 30/05/23 15:32, Joe Simmons-Talbott via Libc-alpha wrote:
> Use a scratch_buffer rather than alloca to avoid potential stack
> overflows.
LGTM, thanks.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
> ---
> sysdeps/unix/sysv/linux/getipv4sourcefilter.c | 24 ++++++-------------
> 1 file changed, 7 insertions(+), 17 deletions(-)
>
> diff --git a/sysdeps/unix/sysv/linux/getipv4sourcefilter.c b/sysdeps/unix/sysv/linux/getipv4sourcefilter.c
> index 8a367b1048..ce72becead 100644
> --- a/sysdeps/unix/sysv/linux/getipv4sourcefilter.c
> +++ b/sysdeps/unix/sysv/linux/getipv4sourcefilter.c
> @@ -16,9 +16,9 @@
> License along with the GNU C Library; if not, see
> <https://www.gnu.org/licenses/>. */
>
> -#include <alloca.h>
> #include <errno.h>
> #include <stdlib.h>
> +#include <scratch_buffer.h>
> #include <string.h>
> #include <stdint.h>
> #include <netinet/in.h>
> @@ -33,17 +33,12 @@ getipv4sourcefilter (int s, struct in_addr interface, struct in_addr group,
> /* We have to create an struct ip_msfilter object which we can pass
> to the kernel. */
> socklen_t needed = IP_MSFILTER_SIZE (*numsrc);
> - int use_alloca = __libc_use_alloca (needed);
>
> - struct ip_msfilter *imsf;
> - if (use_alloca)
> - imsf = (struct ip_msfilter *) alloca (needed);
> - else
> - {
> - imsf = (struct ip_msfilter *) malloc (needed);
> - if (imsf == NULL)
> - return -1;
> - }
> + struct scratch_buffer buf;
> + scratch_buffer_init (&buf);
> + if (!scratch_buffer_set_array_size (&buf, 1, needed))
> + return -1;
> + struct ip_msfilter *imsf = buf.data;
>
> imsf->imsf_multiaddr = group;
> imsf->imsf_interface = interface;
> @@ -61,12 +56,7 @@ getipv4sourcefilter (int s, struct in_addr interface, struct in_addr group,
> *numsrc = imsf->imsf_numsrc;
> }
>
> - if (! use_alloca)
> - {
> - int save_errno = errno;
> - free (imsf);
> - __set_errno (save_errno);
> - }
> + scratch_buffer_free (&buf);
>
> return result;
> }
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] getipv4sourcefilter: Get rid of alloca
2023-05-31 12:37 ` Adhemerval Zanella Netto
@ 2023-06-01 14:20 ` Joe Simmons-Talbott
0 siblings, 0 replies; 3+ messages in thread
From: Joe Simmons-Talbott @ 2023-06-01 14:20 UTC (permalink / raw)
To: Adhemerval Zanella Netto; +Cc: libc-alpha
On Wed, May 31, 2023 at 09:37:15AM -0300, Adhemerval Zanella Netto wrote:
>
>
> On 30/05/23 15:32, Joe Simmons-Talbott via Libc-alpha wrote:
> > Use a scratch_buffer rather than alloca to avoid potential stack
> > overflows.
>
> LGTM, thanks.
>
> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Thanks for the review. Would you mind committing this please?
Thanks,
Joe
>
> > ---
> > sysdeps/unix/sysv/linux/getipv4sourcefilter.c | 24 ++++++-------------
> > 1 file changed, 7 insertions(+), 17 deletions(-)
> >
> > diff --git a/sysdeps/unix/sysv/linux/getipv4sourcefilter.c b/sysdeps/unix/sysv/linux/getipv4sourcefilter.c
> > index 8a367b1048..ce72becead 100644
> > --- a/sysdeps/unix/sysv/linux/getipv4sourcefilter.c
> > +++ b/sysdeps/unix/sysv/linux/getipv4sourcefilter.c
> > @@ -16,9 +16,9 @@
> > License along with the GNU C Library; if not, see
> > <https://www.gnu.org/licenses/>. */
> >
> > -#include <alloca.h>
> > #include <errno.h>
> > #include <stdlib.h>
> > +#include <scratch_buffer.h>
> > #include <string.h>
> > #include <stdint.h>
> > #include <netinet/in.h>
> > @@ -33,17 +33,12 @@ getipv4sourcefilter (int s, struct in_addr interface, struct in_addr group,
> > /* We have to create an struct ip_msfilter object which we can pass
> > to the kernel. */
> > socklen_t needed = IP_MSFILTER_SIZE (*numsrc);
> > - int use_alloca = __libc_use_alloca (needed);
> >
> > - struct ip_msfilter *imsf;
> > - if (use_alloca)
> > - imsf = (struct ip_msfilter *) alloca (needed);
> > - else
> > - {
> > - imsf = (struct ip_msfilter *) malloc (needed);
> > - if (imsf == NULL)
> > - return -1;
> > - }
> > + struct scratch_buffer buf;
> > + scratch_buffer_init (&buf);
> > + if (!scratch_buffer_set_array_size (&buf, 1, needed))
> > + return -1;
> > + struct ip_msfilter *imsf = buf.data;
> >
> > imsf->imsf_multiaddr = group;
> > imsf->imsf_interface = interface;
> > @@ -61,12 +56,7 @@ getipv4sourcefilter (int s, struct in_addr interface, struct in_addr group,
> > *numsrc = imsf->imsf_numsrc;
> > }
> >
> > - if (! use_alloca)
> > - {
> > - int save_errno = errno;
> > - free (imsf);
> > - __set_errno (save_errno);
> > - }
> > + scratch_buffer_free (&buf);
> >
> > return result;
> > }
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2023-05-30 18:32 [PATCH] getipv4sourcefilter: Get rid of alloca Joe Simmons-Talbott
2023-05-31 12:37 ` Adhemerval Zanella Netto
2023-06-01 14:20 ` Joe Simmons-Talbott
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