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migration/rdma: Drop fragile wr_id formatting
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wrid_desc[] uses 4001 pointers to map four integer values to strings.

print_wrid() accesses wrid_desc[] out of bounds when passed a negative
argument.  It returns null for values 2..1999 and 2001..3999.

qemu_rdma_poll() and qemu_rdma_block_for_wrid() print wrid_desc[wr_id]
and passes print_wrid(wr_id) to tracepoints.  Could conceivably crash
trying to format a null string.  I believe access out of bounds is not
possible.

Not worth cleaning up.  Dumb down to show just numeric wr_id.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-5-armbru@redhat.com>
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Markus Armbruster authored and Juan Quintela committed Oct 11, 2023
1 parent 1720a2a commit b5631d5
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Showing 2 changed files with 11 additions and 29 deletions.
32 changes: 7 additions & 25 deletions migration/rdma.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -133,13 +133,6 @@ enum {
RDMA_WRID_RECV_CONTROL = 4000,
};

static const char *wrid_desc[] = {
[RDMA_WRID_NONE] = "NONE",
[RDMA_WRID_RDMA_WRITE] = "WRITE RDMA",
[RDMA_WRID_SEND_CONTROL] = "CONTROL SEND",
[RDMA_WRID_RECV_CONTROL] = "CONTROL RECV",
};

/*
* Work request IDs for IB SEND messages only (not RDMA writes).
* This is used by the migration protocol to transmit
Expand Down Expand Up @@ -535,7 +528,6 @@ static void network_to_result(RDMARegisterResult *result)
result->host_addr = ntohll(result->host_addr);
};

const char *print_wrid(int wrid);
static int qemu_rdma_exchange_send(RDMAContext *rdma, RDMAControlHeader *head,
uint8_t *data, RDMAControlHeader *resp,
int *resp_idx,
Expand Down Expand Up @@ -1362,14 +1354,6 @@ static int qemu_rdma_reg_control(RDMAContext *rdma, int idx)
return -1;
}

const char *print_wrid(int wrid)
{
if (wrid >= RDMA_WRID_RECV_CONTROL) {
return wrid_desc[RDMA_WRID_RECV_CONTROL];
}
return wrid_desc[wrid];
}

/*
* Perform a non-optimized memory unregistration after every transfer
* for demonstration purposes, only if pin-all is not requested.
Expand Down Expand Up @@ -1491,15 +1475,15 @@ static int qemu_rdma_poll(RDMAContext *rdma, struct ibv_cq *cq,
if (wc.status != IBV_WC_SUCCESS) {
fprintf(stderr, "ibv_poll_cq wc.status=%d %s!\n",
wc.status, ibv_wc_status_str(wc.status));
fprintf(stderr, "ibv_poll_cq wrid=%s!\n", wrid_desc[wr_id]);
fprintf(stderr, "ibv_poll_cq wrid=%" PRIu64 "!\n", wr_id);

return -1;
}

if (rdma->control_ready_expected &&
(wr_id >= RDMA_WRID_RECV_CONTROL)) {
trace_qemu_rdma_poll_recv(wrid_desc[RDMA_WRID_RECV_CONTROL],
wr_id - RDMA_WRID_RECV_CONTROL, wr_id, rdma->nb_sent);
trace_qemu_rdma_poll_recv(wr_id - RDMA_WRID_RECV_CONTROL, wr_id,
rdma->nb_sent);
rdma->control_ready_expected = 0;
}

Expand All @@ -1510,7 +1494,7 @@ static int qemu_rdma_poll(RDMAContext *rdma, struct ibv_cq *cq,
(wc.wr_id & RDMA_WRID_BLOCK_MASK) >> RDMA_WRID_BLOCK_SHIFT;
RDMALocalBlock *block = &(rdma->local_ram_blocks.block[index]);

trace_qemu_rdma_poll_write(print_wrid(wr_id), wr_id, rdma->nb_sent,
trace_qemu_rdma_poll_write(wr_id, rdma->nb_sent,
index, chunk, block->local_host_addr,
(void *)(uintptr_t)block->remote_host_addr);

Expand All @@ -1520,7 +1504,7 @@ static int qemu_rdma_poll(RDMAContext *rdma, struct ibv_cq *cq,
rdma->nb_sent--;
}
} else {
trace_qemu_rdma_poll_other(print_wrid(wr_id), wr_id, rdma->nb_sent);
trace_qemu_rdma_poll_other(wr_id, rdma->nb_sent);
}

*wr_id_out = wc.wr_id;
Expand Down Expand Up @@ -1665,8 +1649,7 @@ static int qemu_rdma_block_for_wrid(RDMAContext *rdma, int wrid_requested,
break;
}
if (wr_id != wrid_requested) {
trace_qemu_rdma_block_for_wrid_miss(print_wrid(wrid_requested),
wrid_requested, print_wrid(wr_id), wr_id);
trace_qemu_rdma_block_for_wrid_miss(wrid_requested, wr_id);
}
}

Expand Down Expand Up @@ -1705,8 +1688,7 @@ static int qemu_rdma_block_for_wrid(RDMAContext *rdma, int wrid_requested,
break;
}
if (wr_id != wrid_requested) {
trace_qemu_rdma_block_for_wrid_miss(print_wrid(wrid_requested),
wrid_requested, print_wrid(wr_id), wr_id);
trace_qemu_rdma_block_for_wrid_miss(wrid_requested, wr_id);
}
}

Expand Down
8 changes: 4 additions & 4 deletions migration/trace-events
View file
Original file line number Diff line number Diff line change
Expand Up @@ -208,7 +208,7 @@ qemu_rdma_accept_incoming_migration(void) ""
qemu_rdma_accept_incoming_migration_accepted(void) ""
qemu_rdma_accept_pin_state(bool pin) "%d"
qemu_rdma_accept_pin_verbsc(void *verbs) "Verbs context after listen: %p"
qemu_rdma_block_for_wrid_miss(const char *wcompstr, int wcomp, const char *gcompstr, uint64_t req) "A Wanted wrid %s (%d) but got %s (%" PRIu64 ")"
qemu_rdma_block_for_wrid_miss(int wcomp, uint64_t req) "A Wanted wrid %d but got %" PRIu64
qemu_rdma_cleanup_disconnect(void) ""
qemu_rdma_close(void) ""
qemu_rdma_connect_pin_all_requested(void) ""
Expand All @@ -222,9 +222,9 @@ qemu_rdma_exchange_send_waiting(const char *desc) "Waiting for response %s"
qemu_rdma_exchange_send_received(const char *desc) "Response %s received."
qemu_rdma_fill(size_t control_len, size_t size) "RDMA %zd of %zd bytes already in buffer"
qemu_rdma_init_ram_blocks(int blocks) "Allocated %d local ram block structures"
qemu_rdma_poll_recv(const char *compstr, int64_t comp, int64_t id, int sent) "completion %s #%" PRId64 " received (%" PRId64 ") left %d"
qemu_rdma_poll_write(const char *compstr, int64_t comp, int left, uint64_t block, uint64_t chunk, void *local, void *remote) "completions %s (%" PRId64 ") left %d, block %" PRIu64 ", chunk: %" PRIu64 " %p %p"
qemu_rdma_poll_other(const char *compstr, int64_t comp, int left) "other completion %s (%" PRId64 ") received left %d"
qemu_rdma_poll_recv(int64_t comp, int64_t id, int sent) "completion %" PRId64 " received (%" PRId64 ") left %d"
qemu_rdma_poll_write(int64_t comp, int left, uint64_t block, uint64_t chunk, void *local, void *remote) "completions %" PRId64 " left %d, block %" PRIu64 ", chunk: %" PRIu64 " %p %p"
qemu_rdma_poll_other(int64_t comp, int left) "other completion %" PRId64 " received left %d"
qemu_rdma_post_send_control(const char *desc) "CONTROL: sending %s.."
qemu_rdma_register_and_get_keys(uint64_t len, void *start) "Registering %" PRIu64 " bytes @ %p"
qemu_rdma_register_odp_mr(const char *name) "Try to register On-Demand Paging memory region: %s"
Expand Down

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