| Message ID | 20230516134549.1488655-1-josimmon@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | setsourcefilter: Replace alloca with a scratch_buffer. | expand |
On 16/05/23 10:45, Joe Simmons-Talbott wrote: > Use a scratch_buffer rather than either alloca or malloc to reduce the > possibility of a stack overflow. > > Suggested-by: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org> LGTM, thanks. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > --- > sysdeps/unix/sysv/linux/setsourcefilter.c | 27 ++++++----------------- > 1 file changed, 7 insertions(+), 20 deletions(-) > > diff --git a/sysdeps/unix/sysv/linux/setsourcefilter.c b/sysdeps/unix/sysv/linux/setsourcefilter.c > index 538f4de696..479744f169 100644 > --- a/sysdeps/unix/sysv/linux/setsourcefilter.c > +++ b/sysdeps/unix/sysv/linux/setsourcefilter.c > @@ -16,13 +16,10 @@ > 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> > -#include <stdint.h> > #include <netinet/in.h> > -#include <sys/socket.h> > +#include <scratch_buffer.h> > #include "getsourcefilter.h" > > > @@ -34,17 +31,12 @@ 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; > - } > + 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); > @@ -63,12 +55,7 @@ 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); > - } > + scratch_buffer_free (&buf); > > return result; > }
diff --git a/sysdeps/unix/sysv/linux/setsourcefilter.c b/sysdeps/unix/sysv/linux/setsourcefilter.c index 538f4de696..479744f169 100644 --- a/sysdeps/unix/sysv/linux/setsourcefilter.c +++ b/sysdeps/unix/sysv/linux/setsourcefilter.c @@ -16,13 +16,10 @@ 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> -#include <stdint.h> #include <netinet/in.h> -#include <sys/socket.h> +#include <scratch_buffer.h> #include "getsourcefilter.h" @@ -34,17 +31,12 @@ 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; - } + 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); @@ -63,12 +55,7 @@ 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); - } + scratch_buffer_free (&buf); return result; }