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mac80211_hwsim: Use kstrndup() in place of kasprintf()

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commit 7ea862048317aa76d0f22334202779a25530980c upstream.

syzbot reports a warning:

precision 33020 too large
WARNING: CPU: 0 PID: 9618 at lib/vsprintf.c:2471 set_precision+0x150/0x180 lib/vsprintf.c:2471
 vsnprintf+0xa7b/0x19a0 lib/vsprintf.c:2547
 kvasprintf+0xb2/0x170 lib/kasprintf.c:22
 kasprintf+0xbb/0xf0 lib/kasprintf.c:59
 hwsim_del_radio_nl+0x63a/0x7e0 drivers/net/wireless/mac80211_hwsim.c:3625
 genl_family_rcv_msg_doit net/netlink/genetlink.c:672 [inline]
 ...
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Thus it seems that kasprintf() with "%.*s" format can not be used for
duplicating a string with arbitrary length. Replace it with kstrndup().

Note that later this string is limited to NL80211_WIPHY_NAME_MAXLEN == 64,
but the code is simpler this way.

Reported-by: syzbot+6693adf1698864d21734@syzkaller.appspotmail.com
Reported-by: syzbot+a4aee3f42d7584d76761@syzkaller.appspotmail.com
Cc: stable@kernel.org
Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
Link: https://lore.kernel.org/r/20200410123257.14559-1-tuomas.tynkkynen@iki.fi
[johannes: add note about length limit]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tuomas Tynkkynen 2020-04-10 15:32:57 +03:00 committed by Greg Kroah-Hartman
parent 49d349dddb
commit faed49eaa5
1 changed files with 6 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/net/wireless/mac80211_hwsim.c
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@ -3327,9 +3327,9 @@ static int hwsim_new_radio_nl(struct sk_buff *msg, struct genl_info *info)
param.no_vif = true;
if (info->attrs[HWSIM_ATTR_RADIO_NAME]) {
hwname = kasprintf(GFP_KERNEL, "%.*s",
nla_len(info->attrs[HWSIM_ATTR_RADIO_NAME]),
(char *)nla_data(info->attrs[HWSIM_ATTR_RADIO_NAME]));
hwname = kstrndup((char *)nla_data(info->attrs[HWSIM_ATTR_RADIO_NAME]),
nla_len(info->attrs[HWSIM_ATTR_RADIO_NAME]),
GFP_KERNEL);
if (!hwname)
return -ENOMEM;
param.hwname = hwname;
@ -3385,9 +3385,9 @@ static int hwsim_del_radio_nl(struct sk_buff *msg, struct genl_info *info)
if (info->attrs[HWSIM_ATTR_RADIO_ID]) {
idx = nla_get_u32(info->attrs[HWSIM_ATTR_RADIO_ID]);
} else if (info->attrs[HWSIM_ATTR_RADIO_NAME]) {
hwname = kasprintf(GFP_KERNEL, "%.*s",
nla_len(info->attrs[HWSIM_ATTR_RADIO_NAME]),
(char *)nla_data(info->attrs[HWSIM_ATTR_RADIO_NAME]));
hwname = kstrndup((char *)nla_data(info->attrs[HWSIM_ATTR_RADIO_NAME]),
nla_len(info->attrs[HWSIM_ATTR_RADIO_NAME]),
GFP_KERNEL);
if (!hwname)
return -ENOMEM;
} else