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In bpf_getdltlist(), do not call copyout(9) while holding bpf lock.

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Copy the data into temprorary malloced buffer and drop the lock for
copyout.

Reported, reviewed and tested by:	cem
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
This commit is contained in:
Konstantin Belousov 2016-02-24 22:00:35 +00:00
parent 6607cb5de8
commit 70209aca16
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=296009
1 changed files with 25 additions and 7 deletions
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32
sys/net/bpf.c
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@ -2681,26 +2681,44 @@ bpf_ifdetach(void *arg __unused, struct ifnet *ifp)
static int
bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl)
{
int n, error;
struct ifnet *ifp;
struct bpf_if *bp;
u_int *lst;
int error, n, n1;
BPF_LOCK_ASSERT();
ifp = d->bd_bif->bif_ifp;
again:
n1 = 0;
LIST_FOREACH(bp, &bpf_iflist, bif_next) {
if (bp->bif_ifp == ifp)
n1++;
}
if (bfl->bfl_list == NULL) {
bfl->bfl_len = n1;
return (0);
}
if (n1 > bfl->bfl_len)
return (ENOMEM);
BPF_UNLOCK();
lst = malloc(n1 * sizeof(u_int), M_TEMP, M_WAITOK);
n = 0;
error = 0;
BPF_LOCK();
LIST_FOREACH(bp, &bpf_iflist, bif_next) {
if (bp->bif_ifp != ifp)
continue;
if (bfl->bfl_list != NULL) {
if (n >= bfl->bfl_len)
return (ENOMEM);
error = copyout(&bp->bif_dlt,
bfl->bfl_list + n, sizeof(u_int));
if (n > n1) {
free(lst, M_TEMP);
goto again;
}
lst[n] = bp->bif_dlt;
n++;
}
BPF_UNLOCK();
error = copyout(lst, bfl->bfl_list, sizeof(u_int) * n);
free(lst, M_TEMP);
BPF_LOCK();
bfl->bfl_len = n;
return (error);
}