git: 80a5b26871e9 - main - sbin/ping: allow normal users to specify larger packets

From: Pedro F. Giffuni <pfg_at_FreeBSD.org>
Date: Wed, 16 Oct 2024 01:06:52 UTC
The branch main has been updated by pfg:

URL: https://cgit.FreeBSD.org/src/commit/?id=80a5b26871e90a0ad99d95bd129343471a7a36e3

commit 80a5b26871e90a0ad99d95bd129343471a7a36e3
Author:     Pedro F. Giffuni <pfg@FreeBSD.org>
AuthorDate: 2024-10-15 20:50:04 +0000
Commit:     Pedro F. Giffuni <pfg@FreeBSD.org>
CommitDate: 2024-10-16 01:05:50 +0000

    sbin/ping: allow normal users to specify larger packets
    
    Only super-user could specify a packet size larger than the default 56 bytes.
    This restriction was added by Matt Dillon in 1998 during the BEST days [0].
    This restriction doesn't exist in ping IPV6 or on NetBSD, OpenBSD and Linux.
    
    UMS [1] uses this feature to estimate the client's bandwidth to optimize the
    streaming experience.
    
    [0] DFGit 526f06b278d9252add168aa18b60242c08771165
    [1] UMS: https://github.com/UniversalMediaServer/UniversalMediaServer
    
    Obtained from:  DragonFlyBSD
    Differential Revision:  https://reviews.freebsd.org/D45774
---
 sbin/ping/ping.8 |  3 +--
 sbin/ping/ping.c | 11 +++++------
 2 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/sbin/ping/ping.8 b/sbin/ping/ping.8
index 0eaec196e1e3..951049d0f252 100644
--- a/sbin/ping/ping.8
+++ b/sbin/ping/ping.8
@@ -25,7 +25,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd September 15, 2023
+.Dd October 15, 2024
 .Dt PING 8
 .Os
 .Sh NAME
@@ -312,7 +312,6 @@ with the 8 bytes of
 ICMP
 header data.
 .Pp
-For IPv4, only the super-user may specify values more than default.
 This option cannot be used with ping sweeps.
 .Pp
 For IPv6, you may need to specify
diff --git a/sbin/ping/ping.c b/sbin/ping/ping.c
index d9d544bc75c8..e6b1247af497 100644
--- a/sbin/ping/ping.c
+++ b/sbin/ping/ping.c
@@ -96,8 +96,8 @@
 #define	DEFDATALEN	56		/* default data length */
 #define	FLOOD_BACKOFF	20000		/* usecs to back off if F_FLOOD mode */
 					/* runs out of buffer space */
-#define	MAXIPLEN	(sizeof(struct ip) + MAX_IPOPTLEN)
-#define	MAXICMPLEN	(ICMP_ADVLENMIN + MAX_IPOPTLEN)
+#define	MAXIPLEN	((int)sizeof(struct ip) + MAX_IPOPTLEN)
+#define	MAXPAYLOAD	(IP_MAXPACKET - MAXIPLEN - ICMP_MINLEN)
 #define	MAXWAIT		10000		/* max ms to wait for response */
 #define	MAXALARM	(60 * 60)	/* max seconds for alarm timeout */
 #define	MAXTOS		255
@@ -458,11 +458,10 @@ ping(int argc, char *const *argv)
 				errx(EX_USAGE, "invalid packet size: `%s'",
 				    optarg);
 			datalen = (int)ltmp;
-			if (uid != 0 && datalen > DEFDATALEN) {
-				errno = EPERM;
-				err(EX_NOPERM,
+			if (datalen > MAXPAYLOAD) {
+				errx(EX_USAGE,
 				    "packet size too large: %d > %u",
-				    datalen, DEFDATALEN);
+				    datalen, MAXPAYLOAD);
 			}
 			break;
 		case 'T':		/* multicast TTL */