Consumers of bpfdetach() expect it to remove all bpf_if structs from the
bpf_iflist list which reference the specified ifnet. The existing implementation only removes the first matching bpf_if found in the list, effectively leaking list entries if an ifnet has been bpfattach()ed multiple times with different DLTs. Fix the leak by performing the detach logic in a loop, stopping when all bpf_if structs referencing the specified ifnet have been detached and removed from the bpf_iflist list. Whilst here, also: - Remove the unnecessary "bp->bif_ifp == NULL" check, as a bpf_if should never exist in the list with a NULL ifnet pointer. - Except when INVARIANTS is in the kernel config, silently ignore the case where no bpf_if referencing the specified ifnet is found, as it is harmless and does not require user attention. Reviewed by: csjp MFC after: 1 week
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parent
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commit
9a7e6bac47
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=229898
@ -2253,33 +2253,42 @@ bpfdetach(struct ifnet *ifp)
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{
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struct bpf_if *bp;
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struct bpf_d *d;
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#ifdef INVARIANTS
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int ndetached;
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/* Locate BPF interface information */
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mtx_lock(&bpf_mtx);
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LIST_FOREACH(bp, &bpf_iflist, bif_next) {
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if (ifp == bp->bif_ifp)
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break;
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}
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ndetached = 0;
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#endif
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/* Interface wasn't attached */
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if ((bp == NULL) || (bp->bif_ifp == NULL)) {
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/* Find all bpf_if struct's which reference ifp and detach them. */
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do {
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mtx_lock(&bpf_mtx);
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LIST_FOREACH(bp, &bpf_iflist, bif_next) {
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if (ifp == bp->bif_ifp)
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break;
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}
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if (bp != NULL)
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LIST_REMOVE(bp, bif_next);
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mtx_unlock(&bpf_mtx);
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if (bp != NULL) {
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#ifdef INVARIANTS
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ndetached++;
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#endif
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while ((d = LIST_FIRST(&bp->bif_dlist)) != NULL) {
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bpf_detachd(d);
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BPFD_LOCK(d);
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bpf_wakeup(d);
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BPFD_UNLOCK(d);
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}
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mtx_destroy(&bp->bif_mtx);
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free(bp, M_BPF);
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}
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} while (bp != NULL);
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#ifdef INVARIANTS
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if (ndetached == 0)
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printf("bpfdetach: %s was not attached\n", ifp->if_xname);
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return;
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}
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LIST_REMOVE(bp, bif_next);
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mtx_unlock(&bpf_mtx);
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while ((d = LIST_FIRST(&bp->bif_dlist)) != NULL) {
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bpf_detachd(d);
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BPFD_LOCK(d);
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bpf_wakeup(d);
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BPFD_UNLOCK(d);
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}
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mtx_destroy(&bp->bif_mtx);
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free(bp, M_BPF);
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#endif
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}
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/*
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