[PATCH 1/4] nat: Fix timeslot range in 'show bsc mgcp' VTY command

Currently the inner loop in show_bsc_mgcp iterates of the timeslot interval [0, 31]. Timeslot 0 is not valid, which causes mgcp_timeslot_to_endpoint to generate a corresponding warning and to return an invalid endp value. That value causes an out-of-bound read access, possibly hitting unallocated memory. This patch fixes the loop range by starting with timeslot 1. Note that this does not prevent mgcp_timeslot_to_endpoint from returning an invalid endpoint index when called with arguments not within its domain. Addresses: <000b> ../../include/openbsc/mgcp.h:250 Timeslot should not be 0 [...] vty=0xb4203db0, argc=1, argv=0xbfffebb0) at bsc_nat_vty.c:256 max = 1 con = 0xb4a004f0 i = 0 j = 0 [...] ==15700== ERROR: AddressSanitizer: heap-use-after-free on address 0xb520be4f at pc 0x8062a42 bp 0xbfffeb18 sp 0xbfffeb0c Sponsored-by: On-Waves ehf --- openbsc/src/osmo-bsc_nat/bsc_nat_vty.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c b/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c index 5f4ad28..2b7db2e 100644 --- a/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c +++ b/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c @@ -250,7 +250,7 @@ DEFUN(show_bsc_mgcp, show_bsc_mgcp_cmd, "show bsc mgcp NR", vty_out(vty, "MGCP Status for %d%s", con->cfg->nr, VTY_NEWLINE); max = bsc_mgcp_nr_multiplexes(con->max_endpoints); for (i = 0; i < max; ++i) { - for (j = 0; j < 32; ++j) { + for (j = 1; j < 32; ++j) { endp = mgcp_timeslot_to_endpoint(i, j); vty_out(vty, " Endpoint 0x%x %s%s", endp, con->_endpoint_status[endp] == 0 -- 1.9.1