* [PATCH] setsourcefilter: Use malloc() rather than alloca().
@ 2023-05-11 15:09 Joe Simmons-Talbott
2023-05-15 18:35 ` Adhemerval Zanella Netto
0 siblings, 1 reply; 3+ messages in thread
From: Joe Simmons-Talbott @ 2023-05-11 15:09 UTC (permalink / raw)
To: libc-alpha; +Cc: Joe Simmons-Talbott
To prevent possible stack overflow use malloc() rather than alloca().
---
sysdeps/unix/sysv/linux/setsourcefilter.c | 22 ++++++----------------
1 file changed, 6 insertions(+), 16 deletions(-)
diff --git a/sysdeps/unix/sysv/linux/setsourcefilter.c b/sysdeps/unix/sysv/linux/setsourcefilter.c
index 538f4de696..6678572968 100644
--- a/sysdeps/unix/sysv/linux/setsourcefilter.c
+++ b/sysdeps/unix/sysv/linux/setsourcefilter.c
@@ -16,7 +16,6 @@
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 <string.h>
@@ -34,17 +33,11 @@ setsourcefilter (int s, uint32_t interface, const struct sockaddr *group,
/* We have to create an struct ip_msfilter object which we can pass
to the kernel. */
size_t needed = GROUP_FILTER_SIZE (numsrc);
- int use_alloca = __libc_use_alloca (needed);
struct group_filter *gf;
- if (use_alloca)
- gf = (struct group_filter *) alloca (needed);
- else
- {
- gf = (struct group_filter *) malloc (needed);
- if (gf == NULL)
- return -1;
- }
+ gf = (struct group_filter *) malloc (needed);
+ if (gf == NULL)
+ return -1;
gf->gf_interface = interface;
memcpy (&gf->gf_group, group, grouplen);
@@ -63,12 +56,9 @@ setsourcefilter (int s, uint32_t interface, const struct sockaddr *group,
else
result = __setsockopt (s, sol, MCAST_MSFILTER, gf, needed);
- if (! use_alloca)
- {
- int save_errno = errno;
- free (gf);
- __set_errno (save_errno);
- }
+ int save_errno = errno;
+ free (gf);
+ __set_errno (save_errno);
return result;
}
--
2.39.2
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] setsourcefilter: Use malloc() rather than alloca().
2023-05-11 15:09 [PATCH] setsourcefilter: Use malloc() rather than alloca() Joe Simmons-Talbott
@ 2023-05-15 18:35 ` Adhemerval Zanella Netto
2023-05-15 19:09 ` Joe Simmons-Talbott
0 siblings, 1 reply; 3+ messages in thread
From: Adhemerval Zanella Netto @ 2023-05-15 18:35 UTC (permalink / raw)
To: Joe Simmons-Talbott, libc-alpha
On 11/05/23 12:09, Joe Simmons-Talbott via Libc-alpha wrote:
> To prevent possible stack overflow use malloc() rather than alloca().
> ---
> sysdeps/unix/sysv/linux/setsourcefilter.c | 22 ++++++----------------
> 1 file changed, 6 insertions(+), 16 deletions(-)
>
> diff --git a/sysdeps/unix/sysv/linux/setsourcefilter.c b/sysdeps/unix/sysv/linux/setsourcefilter.c
> index 538f4de696..6678572968 100644
> --- a/sysdeps/unix/sysv/linux/setsourcefilter.c
> +++ b/sysdeps/unix/sysv/linux/setsourcefilter.c
> @@ -16,7 +16,6 @@
> 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 <string.h>
> @@ -34,17 +33,11 @@ setsourcefilter (int s, uint32_t interface, const struct sockaddr *group,
> /* We have to create an struct ip_msfilter object which we can pass
> to the kernel. */
> size_t needed = GROUP_FILTER_SIZE (numsrc);
> - int use_alloca = __libc_use_alloca (needed);
>
> struct group_filter *gf;
> - if (use_alloca)
> - gf = (struct group_filter *) alloca (needed);
> - else
> - {
> - gf = (struct group_filter *) malloc (needed);
> - if (gf == NULL)
> - return -1;
> - }
> + gf = (struct group_filter *) malloc (needed);
> + if (gf == NULL)
> + return -1;
>
> gf->gf_interface = interface;
> memcpy (&gf->gf_group, group, grouplen);
> @@ -63,12 +56,9 @@ setsourcefilter (int s, uint32_t interface, const struct sockaddr *group,
> else
> result = __setsockopt (s, sol, MCAST_MSFILTER, gf, needed);
>
> - if (! use_alloca)
> - {
> - int save_errno = errno;
> - free (gf);
> - __set_errno (save_errno);
> - }
> + int save_errno = errno;
> + free (gf);
> + __set_errno (save_errno);
>
> return result;
> }
free now must preserve errno (check 69fda43b8dd795c3658869633ca0708ed3134006),
so there is no need to save/restore it. The rest looks ok for me.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] setsourcefilter: Use malloc() rather than alloca().
2023-05-15 18:35 ` Adhemerval Zanella Netto
@ 2023-05-15 19:09 ` Joe Simmons-Talbott
0 siblings, 0 replies; 3+ messages in thread
From: Joe Simmons-Talbott @ 2023-05-15 19:09 UTC (permalink / raw)
To: Adhemerval Zanella Netto; +Cc: libc-alpha
On Mon, May 15, 2023 at 03:35:10PM -0300, Adhemerval Zanella Netto wrote:
>
>
> On 11/05/23 12:09, Joe Simmons-Talbott via Libc-alpha wrote:
> > To prevent possible stack overflow use malloc() rather than alloca().
> > ---
> > sysdeps/unix/sysv/linux/setsourcefilter.c | 22 ++++++----------------
> > 1 file changed, 6 insertions(+), 16 deletions(-)
> >
> > diff --git a/sysdeps/unix/sysv/linux/setsourcefilter.c b/sysdeps/unix/sysv/linux/setsourcefilter.c
> > index 538f4de696..6678572968 100644
> > --- a/sysdeps/unix/sysv/linux/setsourcefilter.c
> > +++ b/sysdeps/unix/sysv/linux/setsourcefilter.c
> > @@ -16,7 +16,6 @@
> > 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 <string.h>
> > @@ -34,17 +33,11 @@ setsourcefilter (int s, uint32_t interface, const struct sockaddr *group,
> > /* We have to create an struct ip_msfilter object which we can pass
> > to the kernel. */
> > size_t needed = GROUP_FILTER_SIZE (numsrc);
> > - int use_alloca = __libc_use_alloca (needed);
> >
> > struct group_filter *gf;
> > - if (use_alloca)
> > - gf = (struct group_filter *) alloca (needed);
> > - else
> > - {
> > - gf = (struct group_filter *) malloc (needed);
> > - if (gf == NULL)
> > - return -1;
> > - }
> > + gf = (struct group_filter *) malloc (needed);
> > + if (gf == NULL)
> > + return -1;
> >
> > gf->gf_interface = interface;
> > memcpy (&gf->gf_group, group, grouplen);
> > @@ -63,12 +56,9 @@ setsourcefilter (int s, uint32_t interface, const struct sockaddr *group,
> > else
> > result = __setsockopt (s, sol, MCAST_MSFILTER, gf, needed);
> >
> > - if (! use_alloca)
> > - {
> > - int save_errno = errno;
> > - free (gf);
> > - __set_errno (save_errno);
> > - }
> > + int save_errno = errno;
> > + free (gf);
> > + __set_errno (save_errno);
> >
> > return result;
> > }
>
> free now must preserve errno (check 69fda43b8dd795c3658869633ca0708ed3134006),
> so there is no need to save/restore it. The rest looks ok for me.
>
Thanks. Fixed in v2.
Joe
^ permalink raw reply [flat|nested] 3+ messages in thread
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2023-05-11 15:09 [PATCH] setsourcefilter: Use malloc() rather than alloca() Joe Simmons-Talbott
2023-05-15 18:35 ` Adhemerval Zanella Netto
2023-05-15 19:09 ` Joe Simmons-Talbott
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