Re: [PATCH] net: fix NULL pointer reference in cipso_v4_doi_free
From: 王贇 <hidden>
Date: 2021-08-30 10:14:41
Also in:
lkml, netdev
Just a ping... Should we fix this? Regards, Michael Wang On 2021/8/26 上午11:42, 王贇 wrote:
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> --- 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 099259f..7fbd0b5 100644 --- a/net/ipv4/cipso_ipv4.c +++ b/net/ipv4/cipso_ipv4.c@@ -465,14 +465,16 @@ 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); }