sch_netem: fix a divide by zero in tabledist()

syzbot managed to crash the kernel in tabledist() loading
an empty distribution table.

	t = dist->table[rnd % dist->size];

Simply return an error when such load is attempted.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
This commit is contained in:
Eric Dumazet 2019-09-18 08:05:39 -07:00 committed by Jakub Kicinski
parent 432264e9df
commit b41d936b5e
1 changed files with 1 additions and 1 deletions

View File

@ -777,7 +777,7 @@ static int get_dist_table(struct Qdisc *sch, struct disttable **tbl,
struct disttable *d;
int i;
if (n > NETEM_DIST_MAX)
if (!n || n > NETEM_DIST_MAX)
return -EINVAL;
d = kvmalloc(sizeof(struct disttable) + n * sizeof(s16), GFP_KERNEL);