| Message ID | 20230530183255.637210-1-josimmon@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | getipv4sourcefilter: Get rid of alloca | expand |
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; > }
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; > > } >
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; }