From d9055634a34d4bcb242f84f36c9a7bb1c4019076 Mon Sep 17 00:00:00 2001 From: Joe Simmons-Talbott Date: Tue, 16 May 2023 09:45:49 -0400 Subject: setsourcefilter: Replace alloca with a scratch_buffer. Use a scratch_buffer rather than either alloca or malloc to reduce the possibility of a stack overflow. Suggested-by: Adhemerval Zanella Netto Reviewed-by: Adhemerval Zanella --- 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 538f4de..479744f 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 . */ -#include #include -#include #include -#include #include -#include +#include #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; } -- cgit v1.1