From: Joe Simmons-Talbott <josimmon@redhat.com>
To: libc-alpha@sourceware.org
Cc: Joe Simmons-Talbott <josimmon@redhat.com>
Subject: [PATCH] setipv4sourcefilter: Avoid using alloca.
Date: Wed, 24 May 2023 14:18:31 -0400 [thread overview]
Message-ID: <20230524181831.41099-1-josimmon@redhat.com> (raw)
Use a scratch_buffer rather than alloca/malloc to avoid potential stack
overflow.
---
sysdeps/unix/sysv/linux/setipv4sourcefilter.c | 24 ++++++-------------
1 file changed, 7 insertions(+), 17 deletions(-)
diff --git a/sysdeps/unix/sysv/linux/setipv4sourcefilter.c b/sysdeps/unix/sysv/linux/setipv4sourcefilter.c
index 7f146d789a..8c77ba33bd 100644
--- a/sysdeps/unix/sysv/linux/setipv4sourcefilter.c
+++ b/sysdeps/unix/sysv/linux/setipv4sourcefilter.c
@@ -16,12 +16,12 @@
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 <scratch_buffer.h>
#include <sys/socket.h>
@@ -33,17 +33,12 @@ setipv4sourcefilter (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. */
size_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;
@@ -53,12 +48,7 @@ setipv4sourcefilter (int s, struct in_addr interface, struct in_addr group,
int result = __setsockopt (s, SOL_IP, IP_MSFILTER, imsf, needed);
- if (! use_alloca)
- {
- int save_errno = errno;
- free (imsf);
- __set_errno (save_errno);
- }
+ scratch_buffer_free (&buf);
return result;
}
--
2.39.2
next reply other threads:[~2023-05-24 18:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-24 18:18 Joe Simmons-Talbott [this message]
2023-05-25 2:09 ` Siddhesh Poyarekar
2023-05-25 7:33 ` Florian Weimer
2023-05-25 11:04 ` Adhemerval Zanella Netto
2023-05-25 11:27 ` Florian Weimer
2023-05-25 11:57 ` Siddhesh Poyarekar
2023-05-25 12:20 ` Adhemerval Zanella Netto
2023-05-25 12:25 ` Siddhesh Poyarekar
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