setsourcefilter: Replace alloca with a scratch_buffer.
Checks
| Context |
Check |
Description |
| dj/TryBot-apply_patch |
success
|
Patch applied to master at the time it was sent
|
| dj/TryBot-32bit |
success
|
Build for i686
|
Commit Message
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>
---
sysdeps/unix/sysv/linux/setsourcefilter.c | 27 ++++++-----------------
1 file changed, 7 insertions(+), 20 deletions(-)
Comments
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;
> }
@@ -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;
}