Commit cd8ae32e authored by Sabrina Dubroca's avatar Sabrina Dubroca Committed by Steffen Klassert
Browse files

xfrm: xfrm_alloc_spi shouldn't use 0 as SPI 



x->id.spi == 0 means "no SPI assigned", but since commit
94f39804 ("xfrm: Duplicate SPI Handling"), we now create states
and add them to the byspi list with this value.

__xfrm_state_delete doesn't remove those states from the byspi list,
since they shouldn't be there, and this shows up as a UAF the next
time we go through the byspi list.

Reported-by: default avatar <syzbot+a25ee9d20d31e483ba7b@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=a25ee9d20d31e483ba7b


Fixes: 94f39804 ("xfrm: Duplicate SPI Handling")
Signed-off-by: default avatarSabrina Dubroca <sd@queasysnail.net>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
parent 52565a93

net/xfrm/xfrm_state.c

+3 −0
Original line number Diff line number Diff line
@@ -2583,6 +2583,8 @@ int xfrm_alloc_spi(struct xfrm_state *x, u32 low, u32 high, 


	for (h = 0; h < range; h++) {

		u32 spi = (low == high) ? low : get_random_u32_inclusive(low, high);

		if (spi == 0)

			goto next;

		newspi = htonl(spi);



		spin_lock_bh(&net->xfrm.xfrm_state_lock);
@@ -2598,6 +2600,7 @@ int xfrm_alloc_spi(struct xfrm_state *x, u32 low, u32 high, 
		xfrm_state_put(x0);

		spin_unlock_bh(&net->xfrm.xfrm_state_lock);



next:

		if (signal_pending(current)) {

			err = -ERESTARTSYS;

			goto unlock;