Merge tag 'for-next-keys-7.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd

Pull keys fixes from Jarkko Sakkinen:

 - An unprivileged keyring whose keys collide through the
   description-chunk path can drive assoc_array node splitting
   into an out-of-bounds slot write. Fix it.

 - Fix the DCP trusted keys backend

* tag 'for-next-keys-7.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd:
  assoc_array: trim the final shortcut word using the current chunk end
  keys: make keyring key-chunk byte order agree with keyring_diff_objects()
  keys: fix out-of-bounds read in keyring_get_key_chunk()
  KEYS: trusted: dcp: fix key_len validation and calc_blob_len() return type

3 files changed, 21 insertions, 11 deletions

diff --git a/lib/assoc_array.c b/lib/assoc_array.c
index bcc6e0a013eb..b6c9723e12ce 100644
--- a/lib/assoc_array.c
+++ b/lib/assoc_array.c
@@ -255,7 +255,8 @@ follow_shortcut:
 		sc_segments = shortcut->index_key[sc_level >> ASSOC_ARRAY_KEY_CHUNK_SHIFT];
 		dissimilarity = segments ^ sc_segments;
 
-		if (round_up(sc_level, ASSOC_ARRAY_KEY_CHUNK_SIZE) > shortcut->skip_to_level) {
+		if (shortcut->skip_to_level < round_down(sc_level,
+				ASSOC_ARRAY_KEY_CHUNK_SIZE) + ASSOC_ARRAY_KEY_CHUNK_SIZE) {
 			/* Trim segments that are beyond the shortcut */
 			int shift = shortcut->skip_to_level & ASSOC_ARRAY_KEY_CHUNK_MASK;
 			dissimilarity &= ~(ULONG_MAX << shift);
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 7a2ee0ded7c9..15bf4af8f282 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -271,6 +271,7 @@ static unsigned long keyring_get_key_chunk(const void *data, int level)
 	unsigned long chunk = 0;
 	const u8 *d;
 	int desc_len = index_key->desc_len, n = sizeof(chunk);
+	unsigned int offset;
 
 	level /= ASSOC_ARRAY_KEY_CHUNK_SIZE;
 	switch (level) {
@@ -284,17 +285,18 @@ static unsigned long keyring_get_key_chunk(const void *data, int level)
 		return (unsigned long)index_key->domain_tag;
 	default:
 		level -= 4;
-		if (desc_len <= sizeof(index_key->desc))
+		offset = sizeof(index_key->desc) + level * sizeof(long);
+		if (desc_len <= offset)
 			return 0;
 
-		d = index_key->description + sizeof(index_key->desc);
-		d += level * sizeof(long);
-		desc_len -= sizeof(index_key->desc);
+		d = index_key->description + offset;
+		desc_len -= offset;
 		if (desc_len > n)
 			desc_len = n;
+		d += desc_len;
 		do {
 			chunk <<= 8;
-			chunk |= *d++;
+			chunk |= *--d;
 		} while (--desc_len > 0);
 		return chunk;
 	}
@@ -375,7 +377,7 @@ same:
 	return -1;
 
 differ_plus_i:
-	level += i;
+	level += i - (int)sizeof(a->desc);
 differ:
 	i = level * 8 + __ffs(seg_a ^ seg_b);
 	return i;
diff --git a/security/keys/trusted-keys/trusted_dcp.c b/security/keys/trusted-keys/trusted_dcp.c
index 7b6eb655df0c..c078adebe190 100644
--- a/security/keys/trusted-keys/trusted_dcp.c
+++ b/security/keys/trusted-keys/trusted_dcp.c
@@ -69,7 +69,7 @@ static bool skip_zk_test;
 module_param_named(dcp_skip_zk_test, skip_zk_test, bool, 0);
 MODULE_PARM_DESC(dcp_skip_zk_test, "Don't test whether device keys are zero'ed");
 
-static unsigned int calc_blob_len(unsigned int payload_len)
+static size_t calc_blob_len(unsigned int payload_len)
 {
 	return sizeof(struct dcp_blob_fmt) + payload_len + DCP_BLOB_AUTHLEN;
 }
@@ -200,7 +200,8 @@ static int encrypt_blob_key(u8 *plain_key, u8 *encrypted_key)
 static int trusted_dcp_seal(struct trusted_key_payload *p, char *datablob)
 {
 	struct dcp_blob_fmt *b = (struct dcp_blob_fmt *)p->blob;
-	int blen, ret;
+	size_t blen;
+	int ret;
 	u8 *plain_blob_key;
 
 	blen = calc_blob_len(p->key_len);
@@ -242,7 +243,8 @@ out:
 static int trusted_dcp_unseal(struct trusted_key_payload *p, char *datablob)
 {
 	struct dcp_blob_fmt *b = (struct dcp_blob_fmt *)p->blob;
-	int blen, ret;
+	size_t blen;
+	int ret;
 	u8 *plain_blob_key = NULL;
 
 	if (b->fmt_version != DCP_BLOB_VERSION) {
@@ -253,9 +255,14 @@ static int trusted_dcp_unseal(struct trusted_key_payload *p, char *datablob)
 	}
 
 	p->key_len = le32_to_cpu(b->payload_len);
+	if (p->key_len < MIN_KEY_SIZE || p->key_len > MAX_KEY_SIZE) {
+		ret = -EINVAL;
+		goto out;
+	}
+
 	blen = calc_blob_len(p->key_len);
 	if (blen != p->blob_len) {
-		pr_err("DCP blob has bad length: %i != %i\n", blen,
+		pr_err("DCP blob has bad length: %zu != %u\n", blen,
 		       p->blob_len);
 		ret = -EINVAL;
 		goto out;