[Linux-kernel-mentees] [PATCH] net: team: fix memory leak in __team_options_register

[David Miller]

From: Anant Thazhemadam <anant.thazhemadam at gmail.com>
Date: Mon,  5 Oct 2020 02:25:36 +0530

> The variable "i" isn't initialized back correctly after the first loop
> under the label inst_rollback gets executed.
> 
> The value of "i" is assigned to be option_count - 1, and the ensuing 
> loop (under alloc_rollback) begins by initializing i--. 
> Thus, the value of i when the loop begins execution will now become 
> i = option_count - 2.
> 
> Thus, when kfree(dst_opts[i]) is called in the second loop in this 
> order, (i.e., inst_rollback followed by alloc_rollback), 
> dst_optsp[option_count - 2] is the first element freed, and 
> dst_opts[option_count - 1] does not get freed, and thus, a memory 
> leak is caused.
> 
> This memory leak can be fixed, by assigning i = option_count (instead of
> option_count - 1).
> 
> Fixes: 80f7c6683fe0 ("team: add support for per-port options")
> Reported-by: syzbot+69b804437cfec30deac3 at syzkaller.appspotmail.com
> Tested-by: syzbot+69b804437cfec30deac3 at syzkaller.appspotmail.com
> Signed-off-by: Anant Thazhemadam <anant.thazhemadam at gmail.com>

Applied and queued up for -stable, thank you.