system/freebsd-src
system/freebsd-src
1
0
Fork 0
mirror of https://github.com/freebsd/freebsd-src synced 2024-07-23 19:28:36 +00:00
Code Issues Actions 2 Packages Projects Releases Wiki Activity

netlink: improve edge case when reading out truncated last nlmsg in nb

Browse source 
When there is not enough space for one full message we return it truncated.
This enters special block of code that previously may leave empty buffer
with offset == datalen in the queue.  Avoid that, as dealing later with
empty buffers causes more pain than just avoiding them.  While here add
missing msgrcv increment.
This commit is contained in:
Gleb Smirnoff 2024-01-10 20:51:53 -08:00
parent 26caf57e0b
commit e6f4c31460
1 changed files with 16 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

20
sys/netlink/netlink_domain.c
View file

@ -762,11 +762,23 @@ nl_soreceive(struct socket *so, struct sockaddr **psa, struct uio *uio,
} else if (len == 0 && uio->uio_resid > 0) {
flags |= MSG_TRUNC;
partlen = uio->uio_resid;
if (!peek) {
/* XXX: may leave empty nb */
if (peek)
goto nospace;
datalen += hdr->nlmsg_len;
if (nb->offset + hdr->nlmsg_len ==
nb->datalen) {
/*
* Avoid leaving empty nb.
* Process last nb normally.
* Trust uiomove() to care
* about negative uio_resid.
*/
nb = TAILQ_NEXT(nb, tailq);
overflow = 0;
partlen = 0;
} else
nb->offset += hdr->nlmsg_len;
datalen += hdr->nlmsg_len;
}
msgrcv++;
} else
partlen = 0;
goto nospace;