From: Lin Ma linma@zju.edu.cn
[ Upstream commit 5e2424708da7207087934c5c75211e8584d553a0 ]
The previous commit 4e484b3e969b ("xfrm: rate limit SA mapping change message to user space") added one additional attribute named XFRMA_MTIMER_THRESH and described its type at compat_policy (net/xfrm/xfrm_compat.c).
However, the author forgot to also describe the nla_policy at xfrma_policy (net/xfrm/xfrm_user.c). Hence, this suppose NLA_U32 (4 bytes) value can be faked as empty (0 bytes) by a malicious user, which leads to 4 bytes overflow read and heap information leak when parsing nlattrs.
To exploit this, one malicious user can spray the SLUB objects and then leverage this 4 bytes OOB read to leak the heap data into x->mapping_maxage (see xfrm_update_ae_params(...)), and leak it to userspace via copy_to_user_state_extra(...).
The above bug is assigned CVE-2023-3773. To fix it, this commit just completes the nla_policy description for XFRMA_MTIMER_THRESH, which enforces the length check and avoids such OOB read.
Fixes: 4e484b3e969b ("xfrm: rate limit SA mapping change message to user space") Signed-off-by: Lin Ma linma@zju.edu.cn Reviewed-by: Simon Horman simon.horman@corigine.com Reviewed-by: Leon Romanovsky leonro@nvidia.com Signed-off-by: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/xfrm/xfrm_user.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index d093b4d684a61..8fce2e93bb3b3 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -2757,6 +2757,7 @@ const struct nla_policy xfrma_policy[XFRMA_MAX+1] = { [XFRMA_SET_MARK] = { .type = NLA_U32 }, [XFRMA_SET_MARK_MASK] = { .type = NLA_U32 }, [XFRMA_IF_ID] = { .type = NLA_U32 }, + [XFRMA_MTIMER_THRESH] = { .type = NLA_U32 }, }; EXPORT_SYMBOL_GPL(xfrma_policy);