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authorOndrej Mosnacek <omosnace@redhat.com>2021-04-02 11:56:18 +0300
committerPaul Moore <paul@paul-moore.com>2021-04-02 18:46:37 +0300
commit442dc00f82a9727dc0c48c44f792c168f593c6df (patch)
tree056a44fd675c1b4f0032a2566bf7968d3585af3e /security/selinux
parentee5de60a08b7d8d255722662da461ea159c15538 (diff)
downloadlinux-442dc00f82a9727dc0c48c44f792c168f593c6df.tar.xz
selinux: make nslot handling in avtab more robust
1. Make sure all fileds are initialized in avtab_init(). 2. Slightly refactor avtab_alloc() to use the above fact. 3. Use h->nslot == 0 as a sentinel in the access functions to prevent dereferencing h->htable when it's not allocated. Cc: stable@vger.kernel.org Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'security/selinux')
-rw-r--r--security/selinux/ss/avtab.c21
1 files changed, 11 insertions, 10 deletions
diff --git a/security/selinux/ss/avtab.c b/security/selinux/ss/avtab.c
index 6dcb6aa4db7f..2aee4c965c25 100644
--- a/security/selinux/ss/avtab.c
+++ b/security/selinux/ss/avtab.c
@@ -109,7 +109,7 @@ static int avtab_insert(struct avtab *h, struct avtab_key *key, struct avtab_dat
struct avtab_node *prev, *cur, *newnode;
u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
- if (!h)
+ if (!h || !h->nslot)
return -EINVAL;
hvalue = avtab_hash(key, h->mask);
@@ -154,7 +154,7 @@ avtab_insert_nonunique(struct avtab *h, struct avtab_key *key, struct avtab_datu
struct avtab_node *prev, *cur;
u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
- if (!h)
+ if (!h || !h->nslot)
return NULL;
hvalue = avtab_hash(key, h->mask);
for (prev = NULL, cur = h->htable[hvalue];
@@ -184,7 +184,7 @@ struct avtab_datum *avtab_search(struct avtab *h, struct avtab_key *key)
struct avtab_node *cur;
u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
- if (!h)
+ if (!h || !h->nslot)
return NULL;
hvalue = avtab_hash(key, h->mask);
@@ -220,7 +220,7 @@ avtab_search_node(struct avtab *h, struct avtab_key *key)
struct avtab_node *cur;
u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
- if (!h)
+ if (!h || !h->nslot)
return NULL;
hvalue = avtab_hash(key, h->mask);
@@ -295,6 +295,7 @@ void avtab_destroy(struct avtab *h)
}
kvfree(h->htable);
h->htable = NULL;
+ h->nel = 0;
h->nslot = 0;
h->mask = 0;
}
@@ -303,14 +304,15 @@ void avtab_init(struct avtab *h)
{
h->htable = NULL;
h->nel = 0;
+ h->nslot = 0;
+ h->mask = 0;
}
int avtab_alloc(struct avtab *h, u32 nrules)
{
- u32 mask = 0;
u32 shift = 0;
u32 work = nrules;
- u32 nslot = 0;
+ u32 nslot;
if (nrules == 0)
goto avtab_alloc_out;
@@ -324,16 +326,15 @@ int avtab_alloc(struct avtab *h, u32 nrules)
nslot = 1 << shift;
if (nslot > MAX_AVTAB_HASH_BUCKETS)
nslot = MAX_AVTAB_HASH_BUCKETS;
- mask = nslot - 1;
h->htable = kvcalloc(nslot, sizeof(void *), GFP_KERNEL);
if (!h->htable)
return -ENOMEM;
- avtab_alloc_out:
- h->nel = 0;
h->nslot = nslot;
- h->mask = mask;
+ h->mask = nslot - 1;
+
+avtab_alloc_out:
pr_debug("SELinux: %d avtab hash slots, %d rules.\n",
h->nslot, nrules);
return 0;