git: 7c7c231c1424 - main - netgraph/ng_tag: permit variable length data

[Lutz Donnerhacke]

The branch main has been updated by donner:

URL: https://cgit.FreeBSD.org/src/commit/?id=7c7c231c14246a709270bf3f3a4593208e84d01a

commit 7c7c231c14246a709270bf3f3a4593208e84d01a
Author:     Lutz Donnerhacke <lutz at donnerhacke.de>
AuthorDate: 2021-01-02 13:58:17 +0000
Commit:     Lutz Donnerhacke <donner at FreeBSD.org>
CommitDate: 2021-01-18 12:23:22 +0000

    netgraph/ng_tag: permit variable length data
    
    ng_tag(4) operate on arbitrary data of mbuf_tags(9).  Those structures
    are padded to the next multiple of the alignment by the compiler.
    Hence a valid argument has be at most as long as the data received.
    
    PR:             241462
    Reviewed by:    kp
    Approved by:    kp (mentor)
    MFC after:      2 weeks
    Differential Revision: https://reviews.freebsd.org/D22140
---
 sys/netgraph/ng_tag.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/sys/netgraph/ng_tag.c b/sys/netgraph/ng_tag.c
index 364a0bd83dc0..d46c463fc53a 100644
--- a/sys/netgraph/ng_tag.c
+++ b/sys/netgraph/ng_tag.c
@@ -363,9 +363,8 @@ ng_tag_rcvmsg(node_p node, item_p item, hook_p lasthook)
 			hook_p hook;
 
 			/* Sanity check. */
-			if (msg->header.arglen < sizeof(*hp)
-			    || msg->header.arglen !=
-			    NG_TAG_HOOKIN_SIZE(hp->tag_len))
+			if (msg->header.arglen < sizeof(*hp) ||
+			    msg->header.arglen < NG_TAG_HOOKIN_SIZE(hp->tag_len))
 				ERROUT(EINVAL);
 
 			/* Find hook. */
@@ -385,9 +384,8 @@ ng_tag_rcvmsg(node_p node, item_p item, hook_p lasthook)
 			hook_p hook;
 
 			/* Sanity check. */
-			if (msg->header.arglen < sizeof(*hp)
-			    || msg->header.arglen !=
-			    NG_TAG_HOOKOUT_SIZE(hp->tag_len))
+			if (msg->header.arglen < sizeof(*hp) ||
+			    msg->header.arglen < NG_TAG_HOOKOUT_SIZE(hp->tag_len))
 				ERROUT(EINVAL);
 
 			/* Find hook. */