From 1629347c41dbcfe37945f38b6b7ed4939836ff39 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Wed, 20 May 2020 16:17:38 +0800 Subject: [PATCH] netlabel: cope with NULL catmap mainline inclusion from mainline-v5.7 commit eead1c2ea2509fd754c6da893a94f0e69e83ebe4 category: bugfix bugzilla: 13690 CVE: CVE-2020-10711 ------------------------------------------------- The cipso and calipso code can set the MLS_CAT attribute on successful parsing, even if the corresponding catmap has not been allocated, as per current configuration and external input. Later, selinux code tries to access the catmap if the MLS_CAT flag is present via netlbl_catmap_getlong(). That may cause null ptr dereference while processing incoming network traffic. Address the issue setting the MLS_CAT flag only if the catmap is really allocated. Additionally let netlbl_catmap_getlong() cope with NULL catmap. Reported-by: Matthew Sheets Fixes: 4b8feff251da ("netlabel: fix the horribly broken catmap functions") Fixes: ceba1832b1b2 ("calipso: Set the calipso socket label to match the secattr.") Signed-off-by: Paolo Abeni Acked-by: Paul Moore Signed-off-by: David S. Miller Signed-off-by: Yang Yingliang Reviewed-by: Wenan Mao Signed-off-by: Yang Yingliang --- net/ipv4/cipso_ipv4.c | 6 ++++-- net/ipv6/calipso.c | 3 ++- net/netlabel/netlabel_kapi.c | 6 ++++++ 3 files changed, 12 insertions(+), 3 deletions(-) diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c index f0165c5f376b..a5fe55fa67e9 100644 --- a/net/ipv4/cipso_ipv4.c +++ b/net/ipv4/cipso_ipv4.c @@ -1272,7 +1272,8 @@ static int cipso_v4_parsetag_rbm(const struct cipso_v4_doi *doi_def, return ret_val; } - secattr->flags |= NETLBL_SECATTR_MLS_CAT; + if (secattr->attr.mls.cat) + secattr->flags |= NETLBL_SECATTR_MLS_CAT; } return 0; @@ -1453,7 +1454,8 @@ static int cipso_v4_parsetag_rng(const struct cipso_v4_doi *doi_def, return ret_val; } - secattr->flags |= NETLBL_SECATTR_MLS_CAT; + if (secattr->attr.mls.cat) + secattr->flags |= NETLBL_SECATTR_MLS_CAT; } return 0; diff --git a/net/ipv6/calipso.c b/net/ipv6/calipso.c index 1c0bb9fb76e6..70611784c071 100644 --- a/net/ipv6/calipso.c +++ b/net/ipv6/calipso.c @@ -1061,7 +1061,8 @@ static int calipso_opt_getattr(const unsigned char *calipso, goto getattr_return; } - secattr->flags |= NETLBL_SECATTR_MLS_CAT; + if (secattr->attr.mls.cat) + secattr->flags |= NETLBL_SECATTR_MLS_CAT; } secattr->type = NETLBL_NLTYPE_CALIPSO; diff --git a/net/netlabel/netlabel_kapi.c b/net/netlabel/netlabel_kapi.c index ee3e5b6471a6..15fe2120b310 100644 --- a/net/netlabel/netlabel_kapi.c +++ b/net/netlabel/netlabel_kapi.c @@ -748,6 +748,12 @@ int netlbl_catmap_getlong(struct netlbl_lsm_catmap *catmap, if ((off & (BITS_PER_LONG - 1)) != 0) return -EINVAL; + /* a null catmap is equivalent to an empty one */ + if (!catmap) { + *offset = (u32)-1; + return 0; + } + if (off < catmap->startbit) { off = catmap->startbit; *offset = off; -- GitLab