Re: [PATCH AUTOSEL 5.13 13/14] net: fix NULL pointer reference in cipso_v4_doi_free
From: Dongliang Mu <hidden>
Date: 2021-08-30 12:42:41
Also in:
linux-security-module, lkml, stable
On Mon, Aug 30, 2021 at 8:01 PM Sasha Levin [off-list ref] wrote:
From: 王贇 <redacted> [ Upstream commit 733c99ee8be9a1410287cdbb943887365e83b2d6 ]
Hi Sasha, Michael Wang has sent a v2 patch [1] for this bug and it is merged into netdev/net-next.git. However, the v1 patch is already in the upstream tree. How do you guys handle such a issue? [1] https://lkml.org/lkml/2021/8/30/229
quoted hunk ↗ jump to hunk
In netlbl_cipsov4_add_std() when 'doi_def->map.std' alloc failed, we sometime observe panic: BUG: kernel NULL pointer dereference, address: ... RIP: 0010:cipso_v4_doi_free+0x3a/0x80 ... Call Trace: netlbl_cipsov4_add_std+0xf4/0x8c0 netlbl_cipsov4_add+0x13f/0x1b0 genl_family_rcv_msg_doit.isra.15+0x132/0x170 genl_rcv_msg+0x125/0x240 This is because in cipso_v4_doi_free() there is no check on 'doi_def->map.std' when 'doi_def->type' equal 1, which is possibe, since netlbl_cipsov4_add_std() haven't initialize it before alloc 'doi_def->map.std'. This patch just add the check to prevent panic happen for similar cases. Reported-by: Abaci <redacted> Signed-off-by: Michael Wang <redacted> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> --- net/ipv4/cipso_ipv4.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-)diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c index e0480c6cebaa..16bbd62db791 100644 --- a/net/ipv4/cipso_ipv4.c +++ b/net/ipv4/cipso_ipv4.c@@ -466,14 +466,16 @@ void cipso_v4_doi_free(struct cipso_v4_doi *doi_def) if (!doi_def) return; - switch (doi_def->type) { - case CIPSO_V4_MAP_TRANS: - kfree(doi_def->map.std->lvl.cipso); - kfree(doi_def->map.std->lvl.local); - kfree(doi_def->map.std->cat.cipso); - kfree(doi_def->map.std->cat.local); - kfree(doi_def->map.std); - break; + if (doi_def->map.std) { + switch (doi_def->type) { + case CIPSO_V4_MAP_TRANS: + kfree(doi_def->map.std->lvl.cipso); + kfree(doi_def->map.std->lvl.local); + kfree(doi_def->map.std->cat.cipso); + kfree(doi_def->map.std->cat.local); + kfree(doi_def->map.std); + break; + } } kfree(doi_def); } --2.30.2