| Message ID | 20230530181340.3926125-1-josimmon@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | getsourcefilter: Get rid of alloca. | expand |
On 30/05/23 15:13, 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/getsourcefilter.c | 24 +++++++---------------- > 1 file changed, 7 insertions(+), 17 deletions(-) > > diff --git a/sysdeps/unix/sysv/linux/getsourcefilter.c b/sysdeps/unix/sysv/linux/getsourcefilter.c > index b9ba58c23a..461ad889a9 100644 > --- a/sysdeps/unix/sysv/linux/getsourcefilter.c > +++ b/sysdeps/unix/sysv/linux/getsourcefilter.c > @@ -16,10 +16,10 @@ > License along with the GNU C Library; if not, see > <https://www.gnu.org/licenses/>. */ > > -#include <alloca.h> > #include <assert.h> > #include <errno.h> > #include <stdlib.h> > +#include <scratch_buffer.h> > #include <string.h> > #include <stdint.h> > #include <netatalk/at.h> > @@ -95,17 +95,12 @@ getsourcefilter (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. */ > socklen_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; > - } > + struct scratch_buffer buf; > + scratch_buffer_init (&buf); > + if (!scratch_buffer_set_array_size (&buf, 1, needed)) > + return -1; > + struct group_filter *gf = buf.data; > > gf->gf_interface = interface; > memcpy (&gf->gf_group, group, grouplen); > @@ -135,12 +130,7 @@ getsourcefilter (int s, uint32_t interface, const struct sockaddr *group, > } > } > > - if (! use_alloca) > - { > - int save_errno = errno; > - free (gf); > - __set_errno (save_errno); > - } > + scratch_buffer_free (&buf); > > return result; > }
On Wed, May 31, 2023 at 09:27:30AM -0300, Adhemerval Zanella Netto wrote: > > > On 30/05/23 15:13, 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/getsourcefilter.c | 24 +++++++---------------- > > 1 file changed, 7 insertions(+), 17 deletions(-) > > > > diff --git a/sysdeps/unix/sysv/linux/getsourcefilter.c b/sysdeps/unix/sysv/linux/getsourcefilter.c > > index b9ba58c23a..461ad889a9 100644 > > --- a/sysdeps/unix/sysv/linux/getsourcefilter.c > > +++ b/sysdeps/unix/sysv/linux/getsourcefilter.c > > @@ -16,10 +16,10 @@ > > License along with the GNU C Library; if not, see > > <https://www.gnu.org/licenses/>. */ > > > > -#include <alloca.h> > > #include <assert.h> > > #include <errno.h> > > #include <stdlib.h> > > +#include <scratch_buffer.h> > > #include <string.h> > > #include <stdint.h> > > #include <netatalk/at.h> > > @@ -95,17 +95,12 @@ getsourcefilter (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. */ > > socklen_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; > > - } > > + struct scratch_buffer buf; > > + scratch_buffer_init (&buf); > > + if (!scratch_buffer_set_array_size (&buf, 1, needed)) > > + return -1; > > + struct group_filter *gf = buf.data; > > > > gf->gf_interface = interface; > > memcpy (&gf->gf_group, group, grouplen); > > @@ -135,12 +130,7 @@ getsourcefilter (int s, uint32_t interface, const struct sockaddr *group, > > } > > } > > > > - if (! use_alloca) > > - { > > - int save_errno = errno; > > - free (gf); > > - __set_errno (save_errno); > > - } > > + scratch_buffer_free (&buf); > > > > return result; > > } >
diff --git a/sysdeps/unix/sysv/linux/getsourcefilter.c b/sysdeps/unix/sysv/linux/getsourcefilter.c index b9ba58c23a..461ad889a9 100644 --- a/sysdeps/unix/sysv/linux/getsourcefilter.c +++ b/sysdeps/unix/sysv/linux/getsourcefilter.c @@ -16,10 +16,10 @@ License along with the GNU C Library; if not, see <https://www.gnu.org/licenses/>. */ -#include <alloca.h> #include <assert.h> #include <errno.h> #include <stdlib.h> +#include <scratch_buffer.h> #include <string.h> #include <stdint.h> #include <netatalk/at.h> @@ -95,17 +95,12 @@ getsourcefilter (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. */ socklen_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; - } + struct scratch_buffer buf; + scratch_buffer_init (&buf); + if (!scratch_buffer_set_array_size (&buf, 1, needed)) + return -1; + struct group_filter *gf = buf.data; gf->gf_interface = interface; memcpy (&gf->gf_group, group, grouplen); @@ -135,12 +130,7 @@ getsourcefilter (int s, uint32_t interface, const struct sockaddr *group, } } - if (! use_alloca) - { - int save_errno = errno; - free (gf); - __set_errno (save_errno); - } + scratch_buffer_free (&buf); return result; }