Merge branch 'fixes-v4.16-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull security subsystem fixes from James Morris:

 - keys fixes via David Howells:
      "A collection of fixes for Linux keyrings, mostly thanks to Eric
       Biggers:

        - Fix some PKCS#7 verification issues.

        - Fix handling of unsupported crypto in X.509.

        - Fix too-large allocation in big_key"

 - Seccomp updates via Kees Cook:
      "These are fixes for the get_metadata interface that landed during
       -rc1. While the new selftest is strictly not a bug fix, I think
       it's in the same spirit of avoiding bugs"

 - an IMA build fix from Randy Dunlap

* 'fixes-v4.16-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  integrity/security: fix digsig.c build error with header file
  KEYS: Use individual pages in big_key for crypto buffers
  X.509: fix NULL dereference when restricting key with unsupported_sig
  X.509: fix BUG_ON() when hash algorithm is unsupported
  PKCS#7: fix direct verification of SignerInfo signature
  PKCS#7: fix certificate blacklisting
  PKCS#7: fix certificate chain verification
  seccomp: add a selftest for get_metadata
  ptrace, seccomp: tweak get_metadata behavior slightly
  seccomp, ptrace: switch get_metadata types to arch independent

9 files changed, 179 insertions, 41 deletions

diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c
index 1f4e25f10049..598906b1e28d 100644
--- a/crypto/asymmetric_keys/pkcs7_trust.c
+++ b/crypto/asymmetric_keys/pkcs7_trust.c
@@ -106,6 +106,7 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
                 pr_devel("sinfo %u: Direct signer is key %x\n",
                          sinfo->index, key_serial(key));
                 x509 = NULL;
+                sig = sinfo->sig;
                 goto matched;
         }
         if (PTR_ERR(key) != -ENOKEY)
diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c
index 39e6de0c2761..97c77f66b20d 100644
--- a/crypto/asymmetric_keys/pkcs7_verify.c
+++ b/crypto/asymmetric_keys/pkcs7_verify.c
@@ -270,7 +270,7 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7,
                                 sinfo->index);
                         return 0;
                 }
-                ret = public_key_verify_signature(p->pub, p->sig);
+                ret = public_key_verify_signature(p->pub, x509->sig);
                 if (ret < 0)
                         return ret;
                 x509->signer = p;
@@ -366,8 +366,7 @@ static int pkcs7_verify_one(struct pkcs7_message *pkcs7,
  *
  *  (*) -EBADMSG if some part of the message was invalid, or:
  *
- *  (*) 0 if no signature chains were found to be blacklisted or to contain
- *      unsupported crypto, or:
+ *  (*) 0 if a signature chain passed verification, or:
  *
  *  (*) -EKEYREJECTED if a blacklisted key was encountered, or:
  *
@@ -423,8 +422,11 @@ int pkcs7_verify(struct pkcs7_message *pkcs7,
 
         for (sinfo = pkcs7->signed_infos; sinfo; sinfo = sinfo->next) {
                 ret = pkcs7_verify_one(pkcs7, sinfo);
-                if (sinfo->blacklisted && actual_ret == -ENOPKG)
-                        actual_ret = -EKEYREJECTED;
+                if (sinfo->blacklisted) {
+                        if (actual_ret == -ENOPKG)
+                                actual_ret = -EKEYREJECTED;
+                        continue;
+                }
                 if (ret < 0) {
                         if (ret == -ENOPKG) {
                                 sinfo->unsupported_crypto = true;
diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c
index de996586762a..e929fe1e4106 100644
--- a/crypto/asymmetric_keys/public_key.c
+++ b/crypto/asymmetric_keys/public_key.c
@@ -79,9 +79,11 @@ int public_key_verify_signature(const struct public_key *pkey,
 
         BUG_ON(!pkey);
         BUG_ON(!sig);
-        BUG_ON(!sig->digest);
         BUG_ON(!sig->s);
 
+        if (!sig->digest)
+                return -ENOPKG;
+
         alg_name = sig->pkey_algo;
         if (strcmp(sig->pkey_algo, "rsa") == 0) {
                 /* The data wangled by the RSA algorithm is typically padded
diff --git a/crypto/asymmetric_keys/restrict.c b/crypto/asymmetric_keys/restrict.c
index 86fb68508952..7c93c7728454 100644
--- a/crypto/asymmetric_keys/restrict.c
+++ b/crypto/asymmetric_keys/restrict.c
@@ -67,8 +67,9 @@ __setup("ca_keys=", ca_keys_setup);
  *
  * Returns 0 if the new certificate was accepted, -ENOKEY if we couldn't find a
  * matching parent certificate in the trusted list, -EKEYREJECTED if the
- * signature check fails or the key is blacklisted and some other error if
- * there is a matching certificate but the signature check cannot be performed.
+ * signature check fails or the key is blacklisted, -ENOPKG if the signature
+ * uses unsupported crypto, or some other error if there is a matching
+ * certificate but the signature check cannot be performed.
  */
 int restrict_link_by_signature(struct key *dest_keyring,
                                const struct key_type *type,
@@ -88,6 +89,8 @@ int restrict_link_by_signature(struct key *dest_keyring,
                 return -EOPNOTSUPP;
 
         sig = payload->data[asym_auth];
+        if (!sig)
+                return -ENOPKG;
         if (!sig->auth_ids[0] && !sig->auth_ids[1])
                 return -ENOKEY;
 
@@ -139,6 +142,8 @@ static int key_or_keyring_common(struct key *dest_keyring,
                 return -EOPNOTSUPP;
 
         sig = payload->data[asym_auth];
+        if (!sig)
+                return -ENOPKG;
         if (!sig->auth_ids[0] && !sig->auth_ids[1])
                 return -ENOKEY;
 
@@ -222,9 +227,9 @@ static int key_or_keyring_common(struct key *dest_keyring,
  *
  * Returns 0 if the new certificate was accepted, -ENOKEY if we
  * couldn't find a matching parent certificate in the trusted list,
- * -EKEYREJECTED if the signature check fails, and some other error if
- * there is a matching certificate but the signature check cannot be
- * performed.
+ * -EKEYREJECTED if the signature check fails, -ENOPKG if the signature uses
+ * unsupported crypto, or some other error if there is a matching certificate
+ * but the signature check cannot be performed.
  */
 int restrict_link_by_key_or_keyring(struct key *dest_keyring,
                                     const struct key_type *type,
@@ -249,9 +254,9 @@ int restrict_link_by_key_or_keyring(struct key *dest_keyring,
  *
  * Returns 0 if the new certificate was accepted, -ENOKEY if we
  * couldn't find a matching parent certificate in the trusted list,
- * -EKEYREJECTED if the signature check fails, and some other error if
- * there is a matching certificate but the signature check cannot be
- * performed.
+ * -EKEYREJECTED if the signature check fails, -ENOPKG if the signature uses
+ * unsupported crypto, or some other error if there is a matching certificate
+ * but the signature check cannot be performed.
  */
 int restrict_link_by_key_or_keyring_chain(struct key *dest_keyring,
                                           const struct key_type *type,
diff --git a/include/uapi/linux/ptrace.h b/include/uapi/linux/ptrace.h
index e46d82b91166..d5a1b8a492b9 100644
--- a/include/uapi/linux/ptrace.h
+++ b/include/uapi/linux/ptrace.h
@@ -69,8 +69,8 @@ struct ptrace_peeksiginfo_args {
 #define PTRACE_SECCOMP_GET_METADATA     0x420d
 
 struct seccomp_metadata {
-        unsigned long filter_off;       /* Input: which filter */
-        unsigned int flags;             /* Output: filter's flags */
+        __u64 filter_off;       /* Input: which filter */
+        __u64 flags;            /* Output: filter's flags */
 };
 
 /* Read signals from a shared (process wide) queue */
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 940fa408a288..dc77548167ef 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -1076,14 +1076,16 @@ long seccomp_get_metadata(struct task_struct *task,
 
         size = min_t(unsigned long, size, sizeof(kmd));
 
-        if (copy_from_user(&kmd, data, size))
+        if (size < sizeof(kmd.filter_off))
+                return -EINVAL;
+
+        if (copy_from_user(&kmd.filter_off, data, sizeof(kmd.filter_off)))
                 return -EFAULT;
 
         filter = get_nth_filter(task, kmd.filter_off);
         if (IS_ERR(filter))
                 return PTR_ERR(filter);
 
-        memset(&kmd, 0, sizeof(kmd));
         if (filter->log)
                 kmd.flags |= SECCOMP_FILTER_FLAG_LOG;
 
diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index 6f9e4ce568cd..9bb0a7f2863e 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -18,6 +18,7 @@
 #include <linux/cred.h>
 #include <linux/key-type.h>
 #include <linux/digsig.h>
+#include <linux/vmalloc.h>
 #include <crypto/public_key.h>
 #include <keys/system_keyring.h>
 
diff --git a/security/keys/big_key.c b/security/keys/big_key.c
index 929e14978c42..fa728f662a6f 100644
--- a/security/keys/big_key.c
+++ b/security/keys/big_key.c
@@ -22,6 +22,13 @@
 #include <keys/big_key-type.h>
 #include <crypto/aead.h>
 
+struct big_key_buf {
+        unsigned int            nr_pages;
+        void                    *virt;
+        struct scatterlist      *sg;
+        struct page             *pages[];
+};
+
 /*
  * Layout of key payload words.
  */
@@ -91,10 +98,9 @@ static DEFINE_MUTEX(big_key_aead_lock);
 /*
  * Encrypt/decrypt big_key data
  */
-static int big_key_crypt(enum big_key_op op, u8 *data, size_t datalen, u8 *key)
+static int big_key_crypt(enum big_key_op op, struct big_key_buf *buf, size_t datalen, u8 *key)
 {
         int ret;
-        struct scatterlist sgio;
         struct aead_request *aead_req;
         /* We always use a zero nonce. The reason we can get away with this is
          * because we're using a different randomly generated key for every
@@ -109,8 +115,7 @@ static int big_key_crypt(enum big_key_op op, u8 *data, size_t datalen, u8 *key)
                 return -ENOMEM;
 
         memset(zero_nonce, 0, sizeof(zero_nonce));
-        sg_init_one(&sgio, data, datalen + (op == BIG_KEY_ENC ? ENC_AUTHTAG_SIZE : 0));
-        aead_request_set_crypt(aead_req, &sgio, &sgio, datalen, zero_nonce);
+        aead_request_set_crypt(aead_req, buf->sg, buf->sg, datalen, zero_nonce);
         aead_request_set_callback(aead_req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
         aead_request_set_ad(aead_req, 0);
 
@@ -130,21 +135,81 @@ error:
 }
 
 /*
+ * Free up the buffer.
+ */
+static void big_key_free_buffer(struct big_key_buf *buf)
+{
+        unsigned int i;
+
+        if (buf->virt) {
+                memset(buf->virt, 0, buf->nr_pages * PAGE_SIZE);
+                vunmap(buf->virt);
+        }
+
+        for (i = 0; i < buf->nr_pages; i++)
+                if (buf->pages[i])
+                        __free_page(buf->pages[i]);
+
+        kfree(buf);
+}
+
+/*
+ * Allocate a buffer consisting of a set of pages with a virtual mapping
+ * applied over them.
+ */
+static void *big_key_alloc_buffer(size_t len)
+{
+        struct big_key_buf *buf;
+        unsigned int npg = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+        unsigned int i, l;
+
+        buf = kzalloc(sizeof(struct big_key_buf) +
+                      sizeof(struct page) * npg +
+                      sizeof(struct scatterlist) * npg,
+                      GFP_KERNEL);
+        if (!buf)
+                return NULL;
+
+        buf->nr_pages = npg;
+        buf->sg = (void *)(buf->pages + npg);
+        sg_init_table(buf->sg, npg);
+
+        for (i = 0; i < buf->nr_pages; i++) {
+                buf->pages[i] = alloc_page(GFP_KERNEL);
+                if (!buf->pages[i])
+                        goto nomem;
+
+                l = min_t(size_t, len, PAGE_SIZE);
+                sg_set_page(&buf->sg[i], buf->pages[i], l, 0);
+                len -= l;
+        }
+
+        buf->virt = vmap(buf->pages, buf->nr_pages, VM_MAP, PAGE_KERNEL);
+        if (!buf->virt)
+                goto nomem;
+
+        return buf;
+
+nomem:
+        big_key_free_buffer(buf);
+        return NULL;
+}
+
+/*
  * Preparse a big key
  */
 int big_key_preparse(struct key_preparsed_payload *prep)
 {
+        struct big_key_buf *buf;
         struct path *path = (struct path *)&prep->payload.data[big_key_path];
         struct file *file;
         u8 *enckey;
-        u8 *data = NULL;
         ssize_t written;
-        size_t datalen = prep->datalen;
+        size_t datalen = prep->datalen, enclen = datalen + ENC_AUTHTAG_SIZE;
         int ret;
 
-        ret = -EINVAL;
         if (datalen <= 0 || datalen > 1024 * 1024 || !prep->data)
-                goto error;
+                return -EINVAL;
 
         /* Set an arbitrary quota */
         prep->quotalen = 16;
@@ -157,13 +222,12 @@ int big_key_preparse(struct key_preparsed_payload *prep)
                  *
                  * File content is stored encrypted with randomly generated key.
                  */
-                size_t enclen = datalen + ENC_AUTHTAG_SIZE;
                 loff_t pos = 0;
 
-                data = kmalloc(enclen, GFP_KERNEL);
-                if (!data)
+                buf = big_key_alloc_buffer(enclen);
+                if (!buf)
                         return -ENOMEM;
-                memcpy(data, prep->data, datalen);
+                memcpy(buf->virt, prep->data, datalen);
 
                 /* generate random key */
                 enckey = kmalloc(ENC_KEY_SIZE, GFP_KERNEL);
@@ -176,7 +240,7 @@ int big_key_preparse(struct key_preparsed_payload *prep)
                         goto err_enckey;
 
                 /* encrypt aligned data */
-                ret = big_key_crypt(BIG_KEY_ENC, data, datalen, enckey);
+                ret = big_key_crypt(BIG_KEY_ENC, buf, datalen, enckey);
                 if (ret)
                         goto err_enckey;
 
@@ -187,7 +251,7 @@ int big_key_preparse(struct key_preparsed_payload *prep)
                         goto err_enckey;
                 }
 
-                written = kernel_write(file, data, enclen, &pos);
+                written = kernel_write(file, buf->virt, enclen, &pos);
                 if (written != enclen) {
                         ret = written;
                         if (written >= 0)
@@ -202,7 +266,7 @@ int big_key_preparse(struct key_preparsed_payload *prep)
                 *path = file->f_path;
                 path_get(path);
                 fput(file);
-                kzfree(data);
+                big_key_free_buffer(buf);
         } else {
                 /* Just store the data in a buffer */
                 void *data = kmalloc(datalen, GFP_KERNEL);
@@ -220,7 +284,7 @@ err_fput:
 err_enckey:
         kzfree(enckey);
 error:
-        kzfree(data);
+        big_key_free_buffer(buf);
         return ret;
 }
 
@@ -298,15 +362,15 @@ long big_key_read(const struct key *key, char __user *buffer, size_t buflen)
                 return datalen;
 
         if (datalen > BIG_KEY_FILE_THRESHOLD) {
+                struct big_key_buf *buf;
                 struct path *path = (struct path *)&key->payload.data[big_key_path];
                 struct file *file;
-                u8 *data;
                 u8 *enckey = (u8 *)key->payload.data[big_key_data];
                 size_t enclen = datalen + ENC_AUTHTAG_SIZE;
                 loff_t pos = 0;
 
-                data = kmalloc(enclen, GFP_KERNEL);
-                if (!data)
+                buf = big_key_alloc_buffer(enclen);
+                if (!buf)
                         return -ENOMEM;
 
                 file = dentry_open(path, O_RDONLY, current_cred());
@@ -316,26 +380,26 @@ long big_key_read(const struct key *key, char __user *buffer, size_t buflen)
                 }
 
                 /* read file to kernel and decrypt */
-                ret = kernel_read(file, data, enclen, &pos);
+                ret = kernel_read(file, buf->virt, enclen, &pos);
                 if (ret >= 0 && ret != enclen) {
                         ret = -EIO;
                         goto err_fput;
                 }
 
-                ret = big_key_crypt(BIG_KEY_DEC, data, enclen, enckey);
+                ret = big_key_crypt(BIG_KEY_DEC, buf, enclen, enckey);
                 if (ret)
                         goto err_fput;
 
                 ret = datalen;
 
                 /* copy decrypted data to user */
-                if (copy_to_user(buffer, data, datalen) != 0)
+                if (copy_to_user(buffer, buf->virt, datalen) != 0)
                         ret = -EFAULT;
 
 err_fput:
                 fput(file);
 error:
-                kzfree(data);
+                big_key_free_buffer(buf);
         } else {
                 ret = datalen;
                 if (copy_to_user(buffer, key->payload.data[big_key_data],
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 0b457e8e0f0c..5df609950a66 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -141,6 +141,15 @@ struct seccomp_data {
 #define SECCOMP_FILTER_FLAG_LOG 2
 #endif
 
+#ifndef PTRACE_SECCOMP_GET_METADATA
+#define PTRACE_SECCOMP_GET_METADATA     0x420d
+
+struct seccomp_metadata {
+        __u64 filter_off;       /* Input: which filter */
+        __u64 flags;             /* Output: filter's flags */
+};
+#endif
+
 #ifndef seccomp
 int seccomp(unsigned int op, unsigned int flags, void *args)
 {
@@ -2845,6 +2854,58 @@ TEST(get_action_avail)
         EXPECT_EQ(errno, EOPNOTSUPP);
 }
 
+TEST(get_metadata)
+{
+        pid_t pid;
+        int pipefd[2];
+        char buf;
+        struct seccomp_metadata md;
+
+        ASSERT_EQ(0, pipe(pipefd));
+
+        pid = fork();
+        ASSERT_GE(pid, 0);
+        if (pid == 0) {
+                struct sock_filter filter[] = {
+                        BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
+                };
+                struct sock_fprog prog = {
+                        .len = (unsigned short)ARRAY_SIZE(filter),
+                        .filter = filter,
+                };
+
+                /* one with log, one without */
+                ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER,
+                                     SECCOMP_FILTER_FLAG_LOG, &prog));
+                ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog));
+
+                ASSERT_EQ(0, close(pipefd[0]));
+                ASSERT_EQ(1, write(pipefd[1], "1", 1));
+                ASSERT_EQ(0, close(pipefd[1]));
+
+                while (1)
+                        sleep(100);
+        }
+
+        ASSERT_EQ(0, close(pipefd[1]));
+        ASSERT_EQ(1, read(pipefd[0], &buf, 1));
+
+        ASSERT_EQ(0, ptrace(PTRACE_ATTACH, pid));
+        ASSERT_EQ(pid, waitpid(pid, NULL, 0));
+
+        md.filter_off = 0;
+        ASSERT_EQ(sizeof(md), ptrace(PTRACE_SECCOMP_GET_METADATA, pid, sizeof(md), &md));
+        EXPECT_EQ(md.flags, SECCOMP_FILTER_FLAG_LOG);
+        EXPECT_EQ(md.filter_off, 0);
+
+        md.filter_off = 1;
+        ASSERT_EQ(sizeof(md), ptrace(PTRACE_SECCOMP_GET_METADATA, pid, sizeof(md), &md));
+        EXPECT_EQ(md.flags, 0);
+        EXPECT_EQ(md.filter_off, 1);
+
+        ASSERT_EQ(0, kill(pid, SIGKILL));
+}
+
 /*
  * TODO:
  * - add microbenchmarks