6.16-stable review patch. If anyone has any objections, please let me know.
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From: Sabrina Dubroca sd@queasysnail.net
[ Upstream commit cd8ae32e4e4652db55bce6b9c79267d8946765a9 ]
x->id.spi == 0 means "no SPI assigned", but since commit 94f39804d891 ("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: syzbot+a25ee9d20d31e483ba7b@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=a25ee9d20d31e483ba7b Fixes: 94f39804d891 ("xfrm: Duplicate SPI Handling") Signed-off-by: Sabrina Dubroca sd@queasysnail.net Reviewed-by: Simon Horman horms@kernel.org Signed-off-by: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/xfrm/xfrm_state.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index 86337453709ba..4b2eb260f5c2e 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -2578,6 +2578,8 @@ 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); @@ -2593,6 +2595,7 @@ 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;