| Message ID | 20210401115753.3684-1-lyl2019@mail.ustc.edu.cn (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drbd: Fix a use after free in get_initial_state | expand |
On 4/1/21 1:57 PM, Lv Yunlong wrote: > In get_initial_state, it calls notify_initial_state_done(skb,..) if > cb->args[5]==1. I see that if genlmsg_put() failed in > notify_initial_state_done(), the skb will be freed by nlmsg_free(skb). > Then get_initial_state will goto out and the freed skb will be used by > return value skb->len. > > My patch lets skb_len = skb->len and return the skb_len to avoid the uaf. > > Fixes: a29728463b254 ("drbd: Backport the "events2" command") > Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn> > --- > drivers/block/drbd/drbd_nl.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c > index bf7de4c7b96c..474f84675d0a 100644 > --- a/drivers/block/drbd/drbd_nl.c > +++ b/drivers/block/drbd/drbd_nl.c > @@ -4905,6 +4905,7 @@ static int get_initial_state(struct sk_buff *skb, struct netlink_callback *cb) > struct drbd_state_change *state_change = (struct drbd_state_change *)cb->args[0]; > unsigned int seq = cb->args[2]; > unsigned int n; > + unsigned int skb_len = skb->len; > enum drbd_notification_type flags = 0; > > /* There is no need for taking notification_mutex here: it doesn't > @@ -4915,7 +4916,7 @@ static int get_initial_state(struct sk_buff *skb, struct netlink_callback *cb) > cb->args[5]--; > if (cb->args[5] == 1) { > notify_initial_state_done(skb, seq); > - goto out; > + return skb_len; > } > n = cb->args[4]++; > if (cb->args[4] < cb->args[3]) > Thanks for the patch! I think the problem goes even further: skb can also be freed in the notify_*_state_change -> notify_*_state calls below. Also, at the point where we save skb->len into skb_len, skb is not initialized yet. Maybe it makes more sense to not return a length in the first place here, but an error code instead.
> -----原始邮件----- > 发件人: "Christoph Böhmwalder" <christoph.boehmwalder@linbit.com> > 发送时间: 2021-04-01 21:01:20 (星期四) > 收件人: "Lv Yunlong" <lyl2019@mail.ustc.edu.cn> > 抄送: philipp.reisner@linbit.com, lars.ellenberg@linbit.com, axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, drbd-dev@lists.linbit.com > 主题: Re: [Drbd-dev] [PATCH] drbd: Fix a use after free in get_initial_state > > On 4/1/21 1:57 PM, Lv Yunlong wrote: > > In get_initial_state, it calls notify_initial_state_done(skb,..) if > > cb->args[5]==1. I see that if genlmsg_put() failed in > > notify_initial_state_done(), the skb will be freed by nlmsg_free(skb). > > Then get_initial_state will goto out and the freed skb will be used by > > return value skb->len. > > > > My patch lets skb_len = skb->len and return the skb_len to avoid the uaf. > > > > Fixes: a29728463b254 ("drbd: Backport the "events2" command") > > Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn> > > --- > > drivers/block/drbd/drbd_nl.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c > > index bf7de4c7b96c..474f84675d0a 100644 > > --- a/drivers/block/drbd/drbd_nl.c > > +++ b/drivers/block/drbd/drbd_nl.c > > @@ -4905,6 +4905,7 @@ static int get_initial_state(struct sk_buff *skb, struct netlink_callback *cb) > > struct drbd_state_change *state_change = (struct drbd_state_change *)cb->args[0]; > > unsigned int seq = cb->args[2]; > > unsigned int n; > > + unsigned int skb_len = skb->len; > > enum drbd_notification_type flags = 0; > > > > /* There is no need for taking notification_mutex here: it doesn't > > @@ -4915,7 +4916,7 @@ static int get_initial_state(struct sk_buff *skb, struct netlink_callback *cb) > > cb->args[5]--; > > if (cb->args[5] == 1) { > > notify_initial_state_done(skb, seq); > > - goto out; > > + return skb_len; > > } > > n = cb->args[4]++; > > if (cb->args[4] < cb->args[3]) > > > > Thanks for the patch! > > I think the problem goes even further: skb can also be freed in the > notify_*_state_change -> notify_*_state calls below. > > Also, at the point where we save skb->len into skb_len, skb is not > initialized yet. Maybe it makes more sense to not return a length in the > first place here, but an error code instead. > > -- > Christoph Böhmwalder > LINBIT | Keeping the Digital World Running > DRBD HA — Disaster Recovery — Software defined Storage Ok, I see. I found that drbd_adm_get_initial_state() has called the get_initial_state(), and return -ENOMEM if it calls remember_old_state() failed. So, i think that means if get_initial_state() failed on the notify_initial_state_done(), it should return -ENOMEM too. I will submit the PATCH v2 to fix the first place. The fixes of the further problem is hard for me. Thanks.
> -----原始邮件----- > 发件人: lyl2019@mail.ustc.edu.cn > 发送时间: 2021-04-01 23:13:58 (星期四) > 收件人: "Christoph Böhmwalder" <christoph.boehmwalder@linbit.com> > 抄送: philipp.reisner@linbit.com, lars.ellenberg@linbit.com, axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, drbd-dev@lists.linbit.com > 主题: Re: Re: [Drbd-dev] [PATCH] drbd: Fix a use after free in get_initial_state > > > > > > -----原始邮件----- > > 发件人: "Christoph Böhmwalder" <christoph.boehmwalder@linbit.com> > > 发送时间: 2021-04-01 21:01:20 (星期四) > > 收件人: "Lv Yunlong" <lyl2019@mail.ustc.edu.cn> > > 抄送: philipp.reisner@linbit.com, lars.ellenberg@linbit.com, axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, drbd-dev@lists.linbit.com > > 主题: Re: [Drbd-dev] [PATCH] drbd: Fix a use after free in get_initial_state > > > > On 4/1/21 1:57 PM, Lv Yunlong wrote: > > > In get_initial_state, it calls notify_initial_state_done(skb,..) if > > > cb->args[5]==1. I see that if genlmsg_put() failed in > > > notify_initial_state_done(), the skb will be freed by nlmsg_free(skb). > > > Then get_initial_state will goto out and the freed skb will be used by > > > return value skb->len. > > > > > > My patch lets skb_len = skb->len and return the skb_len to avoid the uaf. > > > > > > Fixes: a29728463b254 ("drbd: Backport the "events2" command") > > > Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn> > > > --- > > > drivers/block/drbd/drbd_nl.c | 3 ++- > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c > > > index bf7de4c7b96c..474f84675d0a 100644 > > > --- a/drivers/block/drbd/drbd_nl.c > > > +++ b/drivers/block/drbd/drbd_nl.c > > > @@ -4905,6 +4905,7 @@ static int get_initial_state(struct sk_buff *skb, struct netlink_callback *cb) > > > struct drbd_state_change *state_change = (struct drbd_state_change *)cb->args[0]; > > > unsigned int seq = cb->args[2]; > > > unsigned int n; > > > + unsigned int skb_len = skb->len; > > > enum drbd_notification_type flags = 0; > > > > > > /* There is no need for taking notification_mutex here: it doesn't > > > @@ -4915,7 +4916,7 @@ static int get_initial_state(struct sk_buff *skb, struct netlink_callback *cb) > > > cb->args[5]--; > > > if (cb->args[5] == 1) { > > > notify_initial_state_done(skb, seq); > > > - goto out; > > > + return skb_len; > > > } > > > n = cb->args[4]++; > > > if (cb->args[4] < cb->args[3]) > > > > > > > Thanks for the patch! > > > > I think the problem goes even further: skb can also be freed in the > > notify_*_state_change -> notify_*_state calls below. > > > > Also, at the point where we save skb->len into skb_len, skb is not > > initialized yet. Maybe it makes more sense to not return a length in the > > first place here, but an error code instead. > > > > -- > > Christoph Böhmwalder > > LINBIT | Keeping the Digital World Running > > DRBD HA — Disaster Recovery — Software defined Storage > > Ok, I see. > I found that drbd_adm_get_initial_state() has called the get_initial_state(), > and return -ENOMEM if it calls remember_old_state() failed. > > So, i think that means if get_initial_state() failed on the notify_initial_state_done(), > it should return -ENOMEM too. > > I will submit the PATCH v2 to fix the first place. The fixes of the further problem is > hard for me. > > Thanks. I found that notify_initial_state_done() uses err = -EMSGSIZE, so the first place should return -EMSGSIZE not -ENOMEM. Sorry.
Hi Lv,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on block/for-next]
[also build test WARNING on linux/master linus/master v5.12-rc5 next-20210401]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Lv-Yunlong/drbd-Fix-a-use-after-free-in-get_initial_state/20210402-015401
base: https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
config: x86_64-randconfig-s021-20210401 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce:
# apt-get install sparse
# sparse version: v0.6.3-279-g6d5d9b42-dirty
# https://github.com/0day-ci/linux/commit/af3f55d6c8730c5c1ce31fda165712091584adb0
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Lv-Yunlong/drbd-Fix-a-use-after-free-in-get_initial_state/20210402-015401
git checkout af3f55d6c8730c5c1ce31fda165712091584adb0
# save the attached .config to linux build tree
make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=x86_64
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
sparse warnings: (new ones prefixed by >>)
>> drivers/block/drbd/drbd_nl.c:4957:1: sparse: sparse: unused label 'out'
drivers/block/drbd/drbd_nl.c: note: in included file:
include/linux/genl_magic_func.h:212:12: sparse: sparse: symbol 'drbd_genl_cmd_to_str' was not declared. Should it be static?
drivers/block/drbd/drbd_nl.c:454:33: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:454:33: sparse: struct disk_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:454:33: sparse: struct disk_conf *
drivers/block/drbd/drbd_nl.c:691:38: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:691:38: sparse: struct net_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:691:38: sparse: struct net_conf *
drivers/block/drbd/drbd_nl.c:793:40: sparse: sparse: mixing different enum types:
drivers/block/drbd/drbd_nl.c:793:40: sparse: int enum drbd_state_rv
drivers/block/drbd/drbd_nl.c:793:40: sparse: unsigned int enum drbd_ret_code
drivers/block/drbd/drbd_nl.c:795:40: sparse: sparse: mixing different enum types:
drivers/block/drbd/drbd_nl.c:795:40: sparse: int enum drbd_state_rv
drivers/block/drbd/drbd_nl.c:795:40: sparse: unsigned int enum drbd_ret_code
drivers/block/drbd/drbd_nl.c:980:18: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:980:18: sparse: struct disk_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:980:18: sparse: struct disk_conf *
drivers/block/drbd/drbd_nl.c:1287:41: sparse: sparse: cast to restricted __be32
drivers/block/drbd/drbd_nl.c:1287:41: sparse: sparse: cast to restricted __be32
drivers/block/drbd/drbd_nl.c:1287:41: sparse: sparse: cast to restricted __be32
drivers/block/drbd/drbd_nl.c:1287:41: sparse: sparse: cast to restricted __be32
drivers/block/drbd/drbd_nl.c:1287:41: sparse: sparse: cast to restricted __be32
drivers/block/drbd/drbd_nl.c:1287:41: sparse: sparse: cast to restricted __be32
drivers/block/drbd/drbd_nl.c:1347:22: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:1347:22: sparse: struct disk_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:1347:22: sparse: struct disk_conf *
drivers/block/drbd/drbd_nl.c:1639:17: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:1639:17: sparse: struct disk_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:1639:17: sparse: struct disk_conf *
drivers/block/drbd/drbd_nl.c:1649:17: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:1649:17: sparse: struct fifo_buffer [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:1649:17: sparse: struct fifo_buffer *
drivers/block/drbd/drbd_nl.c:1872:14: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:1872:14: sparse: struct net_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:1872:14: sparse: struct net_conf *
drivers/block/drbd/drbd_nl.c:2130:39: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:2130:39: sparse: struct disk_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:2130:39: sparse: struct disk_conf *
drivers/block/drbd/drbd_nl.c:2138:13: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:2138:13: sparse: struct disk_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:2138:13: sparse: struct disk_conf *
drivers/block/drbd/drbd_nl.c:2320:50: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:2320:50: sparse: struct disk_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:2320:50: sparse: struct disk_conf *
drivers/block/drbd/drbd_nl.c:2343:45: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:2343:45: sparse: struct net_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:2343:45: sparse: struct net_conf *
drivers/block/drbd/drbd_nl.c:2488:9: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:2488:9: sparse: struct net_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:2488:9: sparse: struct net_conf *
drivers/block/drbd/drbd_nl.c:2651:9: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:2651:9: sparse: struct net_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:2651:9: sparse: struct net_conf *
drivers/block/drbd/drbd_nl.c:2803:27: sparse: sparse: mixing different enum types:
drivers/block/drbd/drbd_nl.c:2883:18: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:2883:18: sparse: struct disk_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:2883:18: sparse: struct disk_conf *
drivers/block/drbd/drbd_nl.c:2923:17: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:2923:17: sparse: struct disk_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:2923:17: sparse: struct disk_conf *
drivers/block/drbd/drbd_nl.c:3461:33: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:3461:33: sparse: struct disk_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:3461:33: sparse: struct disk_conf *
drivers/block/drbd/drbd_nl.c:3586:28: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:3586:28: sparse: struct net_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:3586:28: sparse: struct net_conf *
drivers/block/drbd/drbd_nl.c:3799:29: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:3799:29: sparse: struct disk_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:3799:29: sparse: struct disk_conf *
drivers/block/drbd/drbd_nl.c:3805:22: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:3805:22: sparse: struct net_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:3805:22: sparse: struct net_conf *
drivers/block/drbd/drbd_nl.c:3995:38: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_nl.c:3995:38: sparse: struct net_conf [noderef] __rcu *
drivers/block/drbd/drbd_nl.c:3995:38: sparse: struct net_conf *
drivers/block/drbd/drbd_nl.c:450:9: sparse: sparse: context imbalance in 'highest_fencing_policy' - different lock contexts for basic block
drivers/block/drbd/drbd_nl.c:2185:9: sparse: sparse: context imbalance in 'drbd_adm_attach' - different lock contexts for basic block
drivers/block/drbd/drbd_nl.c: note: in included file:
drivers/block/drbd/drbd_int.h:2141:14: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_int.h:2141:14: sparse: struct net_conf [noderef] __rcu *
drivers/block/drbd/drbd_int.h:2141:14: sparse: struct net_conf *
drivers/block/drbd/drbd_int.h:780:24: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_int.h:780:24: sparse: struct net_conf [noderef] __rcu *
drivers/block/drbd/drbd_int.h:780:24: sparse: struct net_conf *
drivers/block/drbd/drbd_int.h:780:24: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_int.h:780:24: sparse: struct net_conf [noderef] __rcu *
drivers/block/drbd/drbd_int.h:780:24: sparse: struct net_conf *
drivers/block/drbd/drbd_int.h:780:24: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_int.h:780:24: sparse: struct net_conf [noderef] __rcu *
drivers/block/drbd/drbd_int.h:780:24: sparse: struct net_conf *
drivers/block/drbd/drbd_int.h:780:24: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_int.h:780:24: sparse: struct net_conf [noderef] __rcu *
drivers/block/drbd/drbd_int.h:780:24: sparse: struct net_conf *
drivers/block/drbd/drbd_int.h:780:24: sparse: sparse: incompatible types in comparison expression (different address spaces):
drivers/block/drbd/drbd_int.h:780:24: sparse: struct net_conf [noderef] __rcu *
drivers/block/drbd/drbd_int.h:780:24: sparse: struct net_conf *
vim +/out +4957 drivers/block/drbd/drbd_nl.c
a29728463b254c Andreas Gruenbacher 2014-07-31 4902
a29728463b254c Andreas Gruenbacher 2014-07-31 4903 static int get_initial_state(struct sk_buff *skb, struct netlink_callback *cb)
a29728463b254c Andreas Gruenbacher 2014-07-31 4904 {
a29728463b254c Andreas Gruenbacher 2014-07-31 4905 struct drbd_state_change *state_change = (struct drbd_state_change *)cb->args[0];
a29728463b254c Andreas Gruenbacher 2014-07-31 4906 unsigned int seq = cb->args[2];
a29728463b254c Andreas Gruenbacher 2014-07-31 4907 unsigned int n;
af3f55d6c8730c Lv Yunlong 2021-04-01 4908 unsigned int skb_len = skb->len;
a29728463b254c Andreas Gruenbacher 2014-07-31 4909 enum drbd_notification_type flags = 0;
a29728463b254c Andreas Gruenbacher 2014-07-31 4910
a29728463b254c Andreas Gruenbacher 2014-07-31 4911 /* There is no need for taking notification_mutex here: it doesn't
a29728463b254c Andreas Gruenbacher 2014-07-31 4912 matter if the initial state events mix with later state chage
a29728463b254c Andreas Gruenbacher 2014-07-31 4913 events; we can always tell the events apart by the NOTIFY_EXISTS
a29728463b254c Andreas Gruenbacher 2014-07-31 4914 flag. */
a29728463b254c Andreas Gruenbacher 2014-07-31 4915
a29728463b254c Andreas Gruenbacher 2014-07-31 4916 cb->args[5]--;
a29728463b254c Andreas Gruenbacher 2014-07-31 4917 if (cb->args[5] == 1) {
a29728463b254c Andreas Gruenbacher 2014-07-31 4918 notify_initial_state_done(skb, seq);
af3f55d6c8730c Lv Yunlong 2021-04-01 4919 return skb_len;
a29728463b254c Andreas Gruenbacher 2014-07-31 4920 }
a29728463b254c Andreas Gruenbacher 2014-07-31 4921 n = cb->args[4]++;
a29728463b254c Andreas Gruenbacher 2014-07-31 4922 if (cb->args[4] < cb->args[3])
a29728463b254c Andreas Gruenbacher 2014-07-31 4923 flags |= NOTIFY_CONTINUES;
a29728463b254c Andreas Gruenbacher 2014-07-31 4924 if (n < 1) {
a29728463b254c Andreas Gruenbacher 2014-07-31 4925 notify_resource_state_change(skb, seq, state_change->resource,
a29728463b254c Andreas Gruenbacher 2014-07-31 4926 NOTIFY_EXISTS | flags);
a29728463b254c Andreas Gruenbacher 2014-07-31 4927 goto next;
a29728463b254c Andreas Gruenbacher 2014-07-31 4928 }
a29728463b254c Andreas Gruenbacher 2014-07-31 4929 n--;
a29728463b254c Andreas Gruenbacher 2014-07-31 4930 if (n < state_change->n_connections) {
a29728463b254c Andreas Gruenbacher 2014-07-31 4931 notify_connection_state_change(skb, seq, &state_change->connections[n],
a29728463b254c Andreas Gruenbacher 2014-07-31 4932 NOTIFY_EXISTS | flags);
a29728463b254c Andreas Gruenbacher 2014-07-31 4933 goto next;
a29728463b254c Andreas Gruenbacher 2014-07-31 4934 }
a29728463b254c Andreas Gruenbacher 2014-07-31 4935 n -= state_change->n_connections;
a29728463b254c Andreas Gruenbacher 2014-07-31 4936 if (n < state_change->n_devices) {
a29728463b254c Andreas Gruenbacher 2014-07-31 4937 notify_device_state_change(skb, seq, &state_change->devices[n],
a29728463b254c Andreas Gruenbacher 2014-07-31 4938 NOTIFY_EXISTS | flags);
a29728463b254c Andreas Gruenbacher 2014-07-31 4939 goto next;
a29728463b254c Andreas Gruenbacher 2014-07-31 4940 }
a29728463b254c Andreas Gruenbacher 2014-07-31 4941 n -= state_change->n_devices;
a29728463b254c Andreas Gruenbacher 2014-07-31 4942 if (n < state_change->n_devices * state_change->n_connections) {
a29728463b254c Andreas Gruenbacher 2014-07-31 4943 notify_peer_device_state_change(skb, seq, &state_change->peer_devices[n],
a29728463b254c Andreas Gruenbacher 2014-07-31 4944 NOTIFY_EXISTS | flags);
a29728463b254c Andreas Gruenbacher 2014-07-31 4945 goto next;
a29728463b254c Andreas Gruenbacher 2014-07-31 4946 }
a29728463b254c Andreas Gruenbacher 2014-07-31 4947
a29728463b254c Andreas Gruenbacher 2014-07-31 4948 next:
a29728463b254c Andreas Gruenbacher 2014-07-31 4949 if (cb->args[4] == cb->args[3]) {
a29728463b254c Andreas Gruenbacher 2014-07-31 4950 struct drbd_state_change *next_state_change =
a29728463b254c Andreas Gruenbacher 2014-07-31 4951 list_entry(state_change->list.next,
a29728463b254c Andreas Gruenbacher 2014-07-31 4952 struct drbd_state_change, list);
a29728463b254c Andreas Gruenbacher 2014-07-31 4953 cb->args[0] = (long)next_state_change;
a29728463b254c Andreas Gruenbacher 2014-07-31 4954 cb->args[3] = notifications_for_state_change(next_state_change);
a29728463b254c Andreas Gruenbacher 2014-07-31 4955 cb->args[4] = 0;
a29728463b254c Andreas Gruenbacher 2014-07-31 4956 }
a29728463b254c Andreas Gruenbacher 2014-07-31 @4957 out:
a29728463b254c Andreas Gruenbacher 2014-07-31 4958 return skb->len;
a29728463b254c Andreas Gruenbacher 2014-07-31 4959 }
a29728463b254c Andreas Gruenbacher 2014-07-31 4960
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c index bf7de4c7b96c..474f84675d0a 100644 --- a/drivers/block/drbd/drbd_nl.c +++ b/drivers/block/drbd/drbd_nl.c @@ -4905,6 +4905,7 @@ static int get_initial_state(struct sk_buff *skb, struct netlink_callback *cb) struct drbd_state_change *state_change = (struct drbd_state_change *)cb->args[0]; unsigned int seq = cb->args[2]; unsigned int n; + unsigned int skb_len = skb->len; enum drbd_notification_type flags = 0; /* There is no need for taking notification_mutex here: it doesn't @@ -4915,7 +4916,7 @@ static int get_initial_state(struct sk_buff *skb, struct netlink_callback *cb) cb->args[5]--; if (cb->args[5] == 1) { notify_initial_state_done(skb, seq); - goto out; + return skb_len; } n = cb->args[4]++; if (cb->args[4] < cb->args[3])
In get_initial_state, it calls notify_initial_state_done(skb,..) if cb->args[5]==1. I see that if genlmsg_put() failed in notify_initial_state_done(), the skb will be freed by nlmsg_free(skb). Then get_initial_state will goto out and the freed skb will be used by return value skb->len. My patch lets skb_len = skb->len and return the skb_len to avoid the uaf. Fixes: a29728463b254 ("drbd: Backport the "events2" command") Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn> --- drivers/block/drbd/drbd_nl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)