Even if iw did not receive some of the meshconf attributes in response to
NL80211_CMD_GET_MESH_PARAMS, it tries to print that param and gets crashed.
Fix this by adding a condition check before trying to access each of the
mesh conf params.
$ iw dev mesh0 get mesh_param mesh_nolearn
Segmentation fault (core dumped)
(gdb) bt
#0 0x00007f21f54660e9 in nla_get_u8 () from /lib/x86_64-linux-gnu/libnl-3.so.200
#1 0x0000562ba2f5d70d in _print_u8 (a=<optimized out>) at mesh.c:131
#2 0x0000562ba2f5d7ce in print_mesh_param_handler (msg=<optimized out>,
arg=0x562ba2f85758 <_mesh_param_descrs+1080>) at mesh.c:412
#3 0x00007f21f546db9c in nl_recvmsgs_report () from /lib/x86_64-linux-gnu/libnl-3.so.200
#4 0x00007f21f546e059 in nl_recvmsgs () from /lib/x86_64-linux-gnu/libnl-3.so.200
#5 0x0000562ba2f5bb3b in __handle_cmd (state=0x7ffe677bc510, idby=II_NETDEV, argc=<optimized out>,
argv=<optimized out>, cmdout=0x7ffe677bc508) at iw.c:541
#6 0x0000562ba2f4fe0c in __handle_cmd (cmdout=0x7ffe677bc508, argv=0x7ffe677bc658, argc=4, idby=II_NETDEV,
state=0x7ffe677bc510) at iw.c:613
#7 main (argc=4, argv=0x7ffe677bc658) at iw.c:613
(gdb) up 2
#2 0x0000562ba2f5d7ce in print_mesh_param_handler (msg=<optimized out>,
arg=0x562ba2f85758 <_mesh_param_descrs+1080>) at mesh.c:412
412 mdescr->nla_print_fn(mesh_params[mdescr->mesh_param_num]);
(gdb) i local
mdescr = 0x562ba2f85758 <_mesh_param_descrs+1080>
attrs = {0x0 <repeats 35 times>, 0x562ba4002a14, 0x0 <repeats 266 times>}
parent_attr = <optimized out>
mesh_params = {0x0, 0x562ba4002a20, 0x562ba4002a28, 0x562ba4002a30, 0x562ba4002a38, 0x562ba4002a40,
0x562ba4002a48, 0x562ba4002a58, 0x562ba4002a68, 0x562ba4002a70, 0x562ba4002a78, 0x562ba4002a80,
0x562ba4002a88, 0x562ba4002a98, 0x562ba4002aa0, 0x562ba4002a50, 0x562ba4002aa8, 0x562ba4002ab0,
0x562ba4002a90, 0x562ba4002ab8, 0x562ba4002ac0, 0x562ba4002a60, 0x562ba4002ac8, 0x562ba4002ad0,
0x562ba4002ad8, 0x562ba4002ae0, 0x562ba4002ae8, 0x562ba4002af0, 0x562ba4002af8, 0x562ba4002b00, 0x0, 0x0}
gnlh = 0x562ba4002a10
(gdb)
(gdb) p mesh_params[30]
$7 = (struct nlattr *) 0x0
(gdb)
Signed-off-by: Gokul Sivakumar <[email protected]>
---
mesh.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/mesh.c b/mesh.c
index 23b3471..3797335 100644
--- a/mesh.c
+++ b/mesh.c
@@ -401,16 +401,20 @@ static int print_mesh_param_handler(struct nl_msg *msg, void *arg)
for (i = 0; i < ARRAY_SIZE(_mesh_param_descrs); i++) {
mdescr = &_mesh_param_descrs[i];
- printf("%s = ", mdescr->name);
- mdescr->nla_print_fn(mesh_params[mdescr->mesh_param_num]);
- printf("\n");
+ if (mesh_params[mdescr->mesh_param_num]) {
+ printf("%s = ", mdescr->name);
+ mdescr->nla_print_fn(mesh_params[mdescr->mesh_param_num]);
+ printf("\n");
+ }
}
return NL_SKIP;
}
/* print out the mesh parameter */
- mdescr->nla_print_fn(mesh_params[mdescr->mesh_param_num]);
- printf("\n");
+ if (mesh_params[mdescr->mesh_param_num]) {
+ mdescr->nla_print_fn(mesh_params[mdescr->mesh_param_num]);
+ printf("\n");
+ }
return NL_SKIP;
}
--
2.25.1