From 92337c0e620d2162e6fb7f0dbaec286670beefc2 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Wed, 18 Jan 2023 18:40:49 +0000
Subject: [PATCH 01/27] Add function to parse an OID from a string

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 include/mbedtls/oid.h |  14 ++++
 library/oid.c         | 164 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 178 insertions(+)

diff --git a/include/mbedtls/oid.h b/include/mbedtls/oid.h
index a592e63c4..1284aa929 100644
--- a/include/mbedtls/oid.h
+++ b/include/mbedtls/oid.h
@@ -466,6 +466,20 @@ typedef struct mbedtls_oid_descriptor_t {
  */
 int mbedtls_oid_get_numeric_string(char *buf, size_t size, const mbedtls_asn1_buf *oid);
 
+/**
+ * \brief           Translate a string containing a numeric representation
+ *                  of an ASN.1 OID into its encoded form
+ *                  (e.g. "1.2.840.113549" into "\x2A\x86\x48\x86\xF7\x0D")
+ *
+ * \param buf       buffer to put representation in
+ * \param size      size of the buffer
+ * \param oid       OID to translate
+ *
+ * \return          Length of the string written (excluding final NULL) or
+ *                  MBEDTLS_ERR_OID_BUF_TOO_SMALL in case of error
+ */
+int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid, const char *buf, size_t size);
+
 /**
  * \brief          Translate an X.509 extension OID into local values
  *
diff --git a/library/oid.c b/library/oid.c
index 86214b23a..9b8bef6de 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -895,4 +895,168 @@ int mbedtls_oid_get_numeric_string(char *buf, size_t size,
     return (int) (size - n);
 }
 
+static int oid_parse_number(const char **p, const char *bound)
+{
+    int ret = MBEDTLS_ERR_ASN1_INVALID_DATA;
+    int num = 0;
+    while (*p < bound && **p >= '0' && **p <= '9') {
+        ret = 0;
+        if (num > (INT_MAX / 10)) {
+            return MBEDTLS_ERR_OID_BUF_TOO_SMALL;
+        }
+        num *= 10;
+        num += **p - '0';
+        (*p)++;
+    }
+    if (ret != 0) {
+        return ret;
+    } else {
+        return num;
+    }
+}
+
+static size_t oid_subidentifier_num_bytes(unsigned int value)
+{
+    size_t num_bytes = 1;
+    value >>= 7;
+    while (value != 0) {
+        num_bytes++;
+        value >>= 7;
+    }
+    return num_bytes;
+}
+
+static int oid_subidentifier_encode_into(unsigned char **p,
+                                         unsigned char *bound,
+                                         unsigned int value)
+{
+    size_t num_bytes = oid_subidentifier_num_bytes(value);
+    if ((size_t) (bound - *p) < num_bytes) {
+        return MBEDTLS_ERR_OID_BUF_TOO_SMALL;
+    }
+    (*p)[num_bytes - 1] = (unsigned char) (value & 0x7f);
+    value >>= 7;
+
+    for (size_t i = 2; i <= num_bytes; i++) {
+        (*p)[num_bytes - i] = 0x80 | (unsigned char) (value & 0x7f);
+        value >>= 7;
+    }
+    *p += num_bytes;
+
+    return 0;
+}
+
+/* Return the OID for the given x.y.z.... style numeric string  */
+int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
+                                    const char *buf, size_t size)
+{
+    int ret = MBEDTLS_ERR_ASN1_INVALID_DATA;
+
+    const char *str_ptr = buf;
+    const char *str_bound = buf + size;
+    int val = 0;
+    size_t encoded_len;
+
+    int component1 = oid_parse_number(&str_ptr, str_bound);
+    if (component1 < 0) {
+        return component1;
+    }
+    if (component1 > 2) {
+        /* First component can't be > 2 */
+        return MBEDTLS_ERR_ASN1_INVALID_DATA;
+    }
+    if (str_ptr >= str_bound || *str_ptr != '.') {
+        return MBEDTLS_ERR_ASN1_INVALID_DATA;
+    }
+    str_ptr++;
+
+    int component2 = oid_parse_number(&str_ptr, str_bound);
+    if (component2 < 0) {
+        return component2;
+    }
+    if ((component1 < 2) && (component2 > 38)) {
+        /* Root nodes 0 and 1 may have up to 39 children */
+        return MBEDTLS_ERR_ASN1_INVALID_DATA;
+    }
+    if (str_ptr < str_bound && *str_ptr != '\0') {
+        if (*str_ptr == '.') {
+            str_ptr++;
+        } else {
+            return MBEDTLS_ERR_ASN1_INVALID_DATA;
+        }
+    }
+
+    if ((UINT_MAX - (unsigned int) component2) <=
+        ((unsigned int) component1 * 40)) {
+        return MBEDTLS_ERR_OID_BUF_TOO_SMALL;
+    }
+    encoded_len = oid_subidentifier_num_bytes(((unsigned int) component1 * 40)
+                                              + (unsigned int) component2);
+
+    while (str_ptr < str_bound && *str_ptr != '\0') {
+        val = oid_parse_number(&str_ptr, str_bound);
+        if (val < 0) {
+            return val;
+        }
+        if (str_ptr < str_bound && *str_ptr != '\0') {
+            if (*str_ptr == '.') {
+                str_ptr++;
+            } else {
+                return MBEDTLS_ERR_ASN1_INVALID_DATA;
+            }
+        }
+
+        size_t num_bytes = oid_subidentifier_num_bytes(val);
+        if ((SIZE_MAX - encoded_len) <= num_bytes) {
+            return MBEDTLS_ERR_OID_BUF_TOO_SMALL;
+        }
+        encoded_len += num_bytes;
+    }
+
+    oid->p = mbedtls_calloc(encoded_len, sizeof(unsigned char));
+    if (oid->p == NULL) {
+        return MBEDTLS_ERR_ASN1_ALLOC_FAILED;
+    }
+    oid->len = encoded_len;
+
+    /* Now that we've allocated the buffer, go back to the start and encode */
+    str_ptr = buf;
+    unsigned char *out_ptr = oid->p;
+    unsigned char *out_bound = oid->p + oid->len;
+
+    /* No need to do validation this time, as we did it on the first pass */
+    component1 = oid_parse_number(&str_ptr, str_bound);
+    /* Skip past the '.' */
+    str_ptr++;
+    component2 = oid_parse_number(&str_ptr, str_bound);
+    /* Skip past the '.' */
+    str_ptr++;
+    ret = oid_subidentifier_encode_into(&out_ptr, out_bound,
+                                        (component1 * 40) + component2);
+    if (ret != 0) {
+        mbedtls_free(oid->p);
+        oid->p = NULL;
+        oid->len = 0;
+        return ret;
+    }
+    while (str_ptr < str_bound && *str_ptr != '\0') {
+        val = oid_parse_number(&str_ptr, str_bound);
+        if (str_ptr < str_bound && *str_ptr == '.') {
+            /* Skip past the '.' */
+            str_ptr++;
+        }
+
+        ret = oid_subidentifier_encode_into(&out_ptr, out_bound, val);
+        if (ret != 0) {
+            mbedtls_free(oid->p);
+            oid->p = NULL;
+            oid->len = 0;
+            return ret;
+        }
+    }
+    oid->tag = MBEDTLS_ASN1_OID;
+
+    return 0;
+}
+
 #endif /* MBEDTLS_OID_C */

From 0f852c92772e28fb04fc184c62015c223e530e4e Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Wed, 15 Feb 2023 11:09:10 +0000
Subject: [PATCH 02/27] Add tests for OID parsing from string

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 tests/suites/test_suite_oid.data     | 12 ++++++++++++
 tests/suites/test_suite_oid.function | 26 ++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/tests/suites/test_suite_oid.data b/tests/suites/test_suite_oid.data
index b9fa6543d..9e47ef42a 100644
--- a/tests/suites/test_suite_oid.data
+++ b/tests/suites/test_suite_oid.data
@@ -119,3 +119,15 @@ oid_get_numeric_string:"8001":MBEDTLS_ERR_ASN1_INVALID_DATA:""
 
 OID get numeric string - overlong encoding, second subidentifier
 oid_get_numeric_string:"2B8001":MBEDTLS_ERR_ASN1_INVALID_DATA:""
+
+OID from numeric string - hardware module name
+oid_from_numeric_string:"1.3.6.1.5.5.7.8.4":0:"2B06010505070804"
+
+OID from numeric string - multi-byte subidentifier
+oid_from_numeric_string:"1.1.2108":0:"29903C"
+
+OID from numeric string - second component greater than 39
+oid_from_numeric_string:"2.49.0.0.826.0":0:"81010000863A00"
+
+OID from numeric string - multi-byte first subidentifier
+oid_from_numeric_string:"2.999":0:"8837"
diff --git a/tests/suites/test_suite_oid.function b/tests/suites/test_suite_oid.function
index 3004b65fe..329bd8b48 100644
--- a/tests/suites/test_suite_oid.function
+++ b/tests/suites/test_suite_oid.function
@@ -117,3 +117,29 @@ void oid_get_numeric_string(data_t *oid, int error_ret, char *result_str)
     }
 }
 /* END_CASE */
+
+/* BEGIN_CASE */
+void oid_from_numeric_string(char *oid_str, int error_ret,
+                             data_t *exp_oid_buf)
+{
+    mbedtls_asn1_buf oid = { 0, 0, NULL };
+    mbedtls_asn1_buf exp_oid = { 0, 0, NULL };
+    int ret;
+
+    exp_oid.tag = MBEDTLS_ASN1_OID;
+    exp_oid.p = exp_oid_buf->x;
+    exp_oid.len = exp_oid_buf->len;
+
+    ret = mbedtls_oid_from_numeric_string(&oid, oid_str, strlen(oid_str));
+
+    if (error_ret == 0) {
+        TEST_EQUAL(oid.len, exp_oid.len);
+        TEST_ASSERT(memcmp(oid.p, exp_oid.p, oid.len) == 0);
+        mbedtls_free(oid.p);
+        oid.p = NULL;
+        oid.len = 0;
+    } else {
+        TEST_EQUAL(ret, error_ret);
+    }
+}
+/* END_CASE */

From 18ec9d7da120cbd7d916483de69961b6dca41c48 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Mon, 20 Feb 2023 17:18:45 +0000
Subject: [PATCH 03/27] Change some error codes to be more accurate

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 library/oid.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/library/oid.c b/library/oid.c
index 9b8bef6de..996b5419e 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -902,7 +902,7 @@ static int oid_parse_number(const char **p, const char *bound)
     while (*p < bound && **p >= '0' && **p <= '9') {
         ret = 0;
         if (num > (INT_MAX / 10)) {
-            return MBEDTLS_ERR_OID_BUF_TOO_SMALL;
+            return MBEDTLS_ERR_ASN1_INVALID_DATA;
         }
         num *= 10;
         num += **p - '0';
@@ -988,7 +988,7 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
 
     if ((UINT_MAX - (unsigned int) component2) <=
         ((unsigned int) component1 * 40)) {
-        return MBEDTLS_ERR_OID_BUF_TOO_SMALL;
+        return MBEDTLS_ERR_ASN1_INVALID_DATA;
     }
     encoded_len = oid_subidentifier_num_bytes(((unsigned int) component1 * 40)
                                               + (unsigned int) component2);
@@ -1008,7 +1008,7 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
 
         size_t num_bytes = oid_subidentifier_num_bytes(val);
         if ((SIZE_MAX - encoded_len) <= num_bytes) {
-            return MBEDTLS_ERR_OID_BUF_TOO_SMALL;
+            return MBEDTLS_ERR_ASN1_INVALID_DATA;
         }
         encoded_len += num_bytes;
     }

From 03329970dec32c99d40e3129bd998022e49493c7 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Mon, 20 Feb 2023 17:28:36 +0000
Subject: [PATCH 04/27] Correct error in processing of second component

Root nodes 0 and 1 may have up to 40 children (0 - 39), not 39 children
(0 - 38) as previously thought.

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 library/oid.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/library/oid.c b/library/oid.c
index 996b5419e..06127c26e 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -974,8 +974,8 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
     if (component2 < 0) {
         return component2;
     }
-    if ((component1 < 2) && (component2 > 38)) {
-        /* Root nodes 0 and 1 may have up to 39 children */
+    if ((component1 < 2) && (component2 > 39)) {
+        /* Root nodes 0 and 1 may have up to 40 children, numbered 0-39 */
         return MBEDTLS_ERR_ASN1_INVALID_DATA;
     }
     if (str_ptr < str_bound && *str_ptr != '\0') {

From 59400ffed5562cc64b6ea1fb373834e3a1e817e4 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Tue, 21 Feb 2023 15:27:16 +0000
Subject: [PATCH 05/27] Improve header docs and rename parameter

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 include/mbedtls/oid.h | 17 +++++++++++------
 library/oid.c         |  8 ++++----
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/include/mbedtls/oid.h b/include/mbedtls/oid.h
index 1284aa929..49f4af520 100644
--- a/include/mbedtls/oid.h
+++ b/include/mbedtls/oid.h
@@ -470,15 +470,20 @@ int mbedtls_oid_get_numeric_string(char *buf, size_t size, const mbedtls_asn1_bu
  * \brief           Translate a string containing a numeric representation
  *                  of an ASN.1 OID into its encoded form
  *                  (e.g. "1.2.840.113549" into "\x2A\x86\x48\x86\xF7\x0D")
+ *                  On success, this function allocates oid->buf from the
+ *                  heap. It must be free'd by the caller.
  *
- * \param buf       buffer to put representation in
- * \param size      size of the buffer
- * \param oid       OID to translate
+ * \param oid       mbedtls_asn1_buf to populate with the DER-encoded OID
+ * \param oid_str   string representation of the OID to parse
+ * \param size      length of the OID string
  *
- * \return          Length of the string written (excluding final NULL) or
- *                  MBEDTLS_ERR_OID_BUF_TOO_SMALL in case of error
+ * \return          0 if successful
+ * \return          #MBEDTLS_ERR_ASN1_INVALID_DATA if oid_str does not
+ *                  represent a valid OID
+ * \return          #MBEDTLS_ERR_ASN1_ALLOC_FAILED if the function fails to
+ *                  allocate oid->buf
  */
-int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid, const char *buf, size_t size);
+int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid, const char *oid_str, size_t size);
 
 /**
  * \brief          Translate an X.509 extension OID into local values
diff --git a/library/oid.c b/library/oid.c
index 06127c26e..6c62b949b 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -948,12 +948,12 @@ static int oid_subidentifier_encode_into(unsigned char **p,
 
 /* Return the OID for the given x.y.z.... style numeric string  */
 int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
-                                    const char *buf, size_t size)
+                                    const char *oid_str, size_t size)
 {
     int ret = MBEDTLS_ERR_ASN1_INVALID_DATA;
 
-    const char *str_ptr = buf;
-    const char *str_bound = buf + size;
+    const char *str_ptr = oid_str;
+    const char *str_bound = oid_str + size;
     int val = 0;
     size_t encoded_len;
 
@@ -1020,7 +1020,7 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
     oid->len = encoded_len;
 
     /* Now that we've allocated the buffer, go back to the start and encode */
-    str_ptr = buf;
+    str_ptr = oid_str;
     unsigned char *out_ptr = oid->p;
     unsigned char *out_bound = oid->p + oid->len;
 

From 0f4ee418d8f4a7b9e46eb953f29a8e07d2f854e0 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Tue, 21 Feb 2023 16:17:41 +0000
Subject: [PATCH 06/27] Use return for errors only in oid_parse_number()

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 library/oid.c | 47 +++++++++++++++++++++--------------------------
 1 file changed, 21 insertions(+), 26 deletions(-)

diff --git a/library/oid.c b/library/oid.c
index 6c62b949b..91f6da6e5 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -895,24 +895,20 @@ int mbedtls_oid_get_numeric_string(char *buf, size_t size,
     return (int) (size - n);
 }
 
-static int oid_parse_number(const char **p, const char *bound)
+static int oid_parse_number(unsigned int *num, const char **p, const char *bound)
 {
     int ret = MBEDTLS_ERR_ASN1_INVALID_DATA;
-    int num = 0;
+    *num = 0;
     while (*p < bound && **p >= '0' && **p <= '9') {
         ret = 0;
-        if (num > (INT_MAX / 10)) {
+        if (*num > (INT_MAX / 10)) {
             return MBEDTLS_ERR_ASN1_INVALID_DATA;
         }
-        num *= 10;
-        num += **p - '0';
+        *num *= 10;
+        *num += **p - '0';
         (*p)++;
     }
-    if (ret != 0) {
-        return ret;
-    } else {
-        return num;
-    }
+    return ret;
 }
 
 static size_t oid_subidentifier_num_bytes(unsigned int value)
@@ -956,10 +952,11 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
     const char *str_bound = oid_str + size;
     int val = 0;
     size_t encoded_len;
+    unsigned int component1, component2;
 
-    int component1 = oid_parse_number(&str_ptr, str_bound);
-    if (component1 < 0) {
-        return component1;
+    ret = oid_parse_number(&component1, &str_ptr, str_bound);
+    if (ret != 0) {
+        return ret;
     }
     if (component1 > 2) {
         /* First component can't be > 2 */
@@ -970,9 +967,9 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
     }
     str_ptr++;
 
-    int component2 = oid_parse_number(&str_ptr, str_bound);
-    if (component2 < 0) {
-        return component2;
+    ret = oid_parse_number(&component2, &str_ptr, str_bound);
+    if (ret != 0) {
+        return ret;
     }
     if ((component1 < 2) && (component2 > 39)) {
         /* Root nodes 0 and 1 may have up to 40 children, numbered 0-39 */
@@ -986,17 +983,15 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
         }
     }
 
-    if ((UINT_MAX - (unsigned int) component2) <=
-        ((unsigned int) component1 * 40)) {
+    if ((UINT_MAX - component2) <= (component1 * 40)) {
         return MBEDTLS_ERR_ASN1_INVALID_DATA;
     }
-    encoded_len = oid_subidentifier_num_bytes(((unsigned int) component1 * 40)
-                                              + (unsigned int) component2);
+    encoded_len = oid_subidentifier_num_bytes((component1 * 40) + component2);
 
     while (str_ptr < str_bound && *str_ptr != '\0') {
-        val = oid_parse_number(&str_ptr, str_bound);
-        if (val < 0) {
-            return val;
+        oid_parse_number(&val, &str_ptr, str_bound);
+        if (ret != 0) {
+            return ret;
         }
         if (str_ptr < str_bound && *str_ptr != '\0') {
             if (*str_ptr == '.') {
@@ -1025,10 +1020,10 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
     unsigned char *out_bound = oid->p + oid->len;
 
     /* No need to do validation this time, as we did it on the first pass */
-    component1 = oid_parse_number(&str_ptr, str_bound);
+    oid_parse_number(&component1, &str_ptr, str_bound);
     /* Skip past the '.' */
     str_ptr++;
-    component2 = oid_parse_number(&str_ptr, str_bound);
+    oid_parse_number(&component2, &str_ptr, str_bound);
     /* Skip past the '.' */
     str_ptr++;
     ret = oid_subidentifier_encode_into(&out_ptr, out_bound,
@@ -1040,7 +1035,7 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
         return ret;
     }
     while (str_ptr < str_bound && *str_ptr != '\0') {
-        val = oid_parse_number(&str_ptr, str_bound);
+        oid_parse_number(&val, &str_ptr, str_bound);
         if (str_ptr < str_bound && *str_ptr == '.') {
             /* Skip past the '.' */
             str_ptr++;

From 7cdfda12da9619e68e15c8516654c8018f4463f3 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Tue, 21 Feb 2023 16:20:52 +0000
Subject: [PATCH 07/27] Fixup: Correct signedness of val local variable

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 library/oid.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/library/oid.c b/library/oid.c
index 91f6da6e5..3b5b31a5e 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -950,7 +950,7 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
 
     const char *str_ptr = oid_str;
     const char *str_bound = oid_str + size;
-    int val = 0;
+    unsigned int val = 0;
     size_t encoded_len;
     unsigned int component1, component2;
 

From 89d67bd472dec4aff1b770004da3a488ac749051 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Tue, 21 Feb 2023 16:24:38 +0000
Subject: [PATCH 08/27] Remove superfluous sizeof(unsigned char)

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 library/oid.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/library/oid.c b/library/oid.c
index 3b5b31a5e..103199012 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -1008,7 +1008,7 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
         encoded_len += num_bytes;
     }
 
-    oid->p = mbedtls_calloc(encoded_len, sizeof(unsigned char));
+    oid->p = mbedtls_calloc(encoded_len, 1);
     if (oid->p == NULL) {
         return MBEDTLS_ERR_ASN1_ALLOC_FAILED;
     }

From 376e8df9d6098539c7ece0bbbce99214f1d5b412 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Tue, 21 Feb 2023 16:33:40 +0000
Subject: [PATCH 09/27] Clarify structure of parsing with comments:

1. Parse through to get the required buffer length.
2. Having allocated a buffer, parse into the buffer.

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 library/oid.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/library/oid.c b/library/oid.c
index 103199012..811d34324 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -954,6 +954,8 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
     size_t encoded_len;
     unsigned int component1, component2;
 
+    /* First pass - parse the string to get the length of buffer required */
+
     ret = oid_parse_number(&component1, &str_ptr, str_bound);
     if (ret != 0) {
         return ret;
@@ -1014,7 +1016,9 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
     }
     oid->len = encoded_len;
 
-    /* Now that we've allocated the buffer, go back to the start and encode */
+    /* Second pass - now that we've allocated the buffer, go back to the
+     * start and encode */
+
     str_ptr = oid_str;
     unsigned char *out_ptr = oid->p;
     unsigned char *out_bound = oid->p + oid->len;

From e91cbcfb2cbc66705e0b7bc9058ca332b89d8d28 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Tue, 21 Feb 2023 17:19:45 +0000
Subject: [PATCH 10/27] Add negative test cases for OID parsing

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 tests/suites/test_suite_oid.data | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/tests/suites/test_suite_oid.data b/tests/suites/test_suite_oid.data
index 9e47ef42a..d4a7dea21 100644
--- a/tests/suites/test_suite_oid.data
+++ b/tests/suites/test_suite_oid.data
@@ -131,3 +131,30 @@ oid_from_numeric_string:"2.49.0.0.826.0":0:"81010000863A00"
 
 OID from numeric string - multi-byte first subidentifier
 oid_from_numeric_string:"2.999":0:"8837"
+
+OID from numeric string - empty string input
+oid_from_numeric_string:"":MBEDTLS_ERR_ASN1_INVALID_DATA:""
+
+OID from numeric string - first component not a number
+oid_from_numeric_string:"abc.1.2":MBEDTLS_ERR_ASN1_INVALID_DATA:""
+
+OID from numeric string - second component not a number
+oid_from_numeric_string:"1.abc.2":MBEDTLS_ERR_ASN1_INVALID_DATA:""
+
+OID from numeric string - first component too large
+oid_from_numeric_string:"3.1":MBEDTLS_ERR_ASN1_INVALID_DATA:""
+
+OID from numeric string - first component < 2, second > 39
+oid_from_numeric_string:"1.40":MBEDTLS_ERR_ASN1_INVALID_DATA:""
+
+OID from numeric string - third component not a number
+oid_from_numeric_string:"1.2.abc":MBEDTLS_ERR_ASN1_INVALID_DATA:""
+
+OID from numeric string - non-'.' separator between first and second
+oid_from_numeric_string:"1/2.3.4":MBEDTLS_ERR_ASN1_INVALID_DATA:""
+
+OID from numeric string - non-'.' separator between second and third
+oid_from_numeric_string:"1.2/3.4":MBEDTLS_ERR_ASN1_INVALID_DATA:""
+
+OID from numeric string - non-'.' separator between third and fourth
+oid_from_numeric_string:"1.2.3/4":MBEDTLS_ERR_ASN1_INVALID_DATA:""

From ce16474d9119cdef01aa6bda53d0210d0821b853 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Thu, 23 Feb 2023 13:50:48 +0000
Subject: [PATCH 11/27] Correct INT_MAX overflow check to UINT_MAX

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 library/oid.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/library/oid.c b/library/oid.c
index 811d34324..3c27bfc73 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -901,7 +901,7 @@ static int oid_parse_number(unsigned int *num, const char **p, const char *bound
     *num = 0;
     while (*p < bound && **p >= '0' && **p <= '9') {
         ret = 0;
-        if (*num > (INT_MAX / 10)) {
+        if (*num > (UINT_MAX / 10)) {
             return MBEDTLS_ERR_ASN1_INVALID_DATA;
         }
         *num *= 10;

From 099be74d28edd04dff9753751c2f0f6a5cdeb9fe Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Thu, 23 Feb 2023 13:51:43 +0000
Subject: [PATCH 12/27] Change free'd to freed for consistency

Also clarify that the user must use mbedtls_free().

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 include/mbedtls/oid.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/mbedtls/oid.h b/include/mbedtls/oid.h
index 49f4af520..b2f5dd196 100644
--- a/include/mbedtls/oid.h
+++ b/include/mbedtls/oid.h
@@ -471,7 +471,7 @@ int mbedtls_oid_get_numeric_string(char *buf, size_t size, const mbedtls_asn1_bu
  *                  of an ASN.1 OID into its encoded form
  *                  (e.g. "1.2.840.113549" into "\x2A\x86\x48\x86\xF7\x0D")
  *                  On success, this function allocates oid->buf from the
- *                  heap. It must be free'd by the caller.
+ *                  heap. It must be freed by the caller using mbedtls_free().
  *
  * \param oid       mbedtls_asn1_buf to populate with the DER-encoded OID
  * \param oid_str   string representation of the OID to parse

From 861e5d2742ddcdd68ab89e8177aa85381eb12ff0 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Wed, 19 Apr 2023 18:15:51 +0100
Subject: [PATCH 13/27] Change to using an alloc-realloc strategy

Allocate enough memory to guarantee we can store the OID, encode into
the buffer, then realloc and copy into a buffer of exactly the right
size.

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 library/oid.c | 119 +++++++++++++++++++++++++-------------------------
 1 file changed, 60 insertions(+), 59 deletions(-)

diff --git a/library/oid.c b/library/oid.c
index 3c27bfc73..139a707c8 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -951,111 +951,112 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
     const char *str_ptr = oid_str;
     const char *str_bound = oid_str + size;
     unsigned int val = 0;
-    size_t encoded_len;
     unsigned int component1, component2;
 
-    /* First pass - parse the string to get the length of buffer required */
+    /* Count the number of dots to get a worst-case allocation size. */
+    size_t num_dots = 0;
+    for (size_t i = 0; (i < size) && (oid_str[i] != '\0'); i++) {
+        if (oid_str[i] == '.') {
+            num_dots++;
+        }
+    }
+    /* Allocate maximum possible required memory:
+     * There are (num_dots + 1) integer components, but the first 2 share the
+     * same subidentifier, so we only need num_dots subidentifiers maximum. */
+    if (num_dots == 0 || (num_dots > SIZE_MAX / sizeof(unsigned int))) {
+        return MBEDTLS_ERR_ASN1_INVALID_DATA;
+    }
+    size_t max_possible_bytes = num_dots * sizeof(unsigned int);
+    oid->p = mbedtls_calloc(max_possible_bytes, 1);
+    if (oid->p == NULL) {
+        return MBEDTLS_ERR_ASN1_ALLOC_FAILED;
+    }
+    unsigned char *out_ptr = oid->p;
+    unsigned char *out_bound = oid->p + max_possible_bytes;
 
     ret = oid_parse_number(&component1, &str_ptr, str_bound);
     if (ret != 0) {
-        return ret;
+        goto error;
     }
     if (component1 > 2) {
         /* First component can't be > 2 */
-        return MBEDTLS_ERR_ASN1_INVALID_DATA;
+        ret = MBEDTLS_ERR_ASN1_INVALID_DATA;
+        goto error;
     }
     if (str_ptr >= str_bound || *str_ptr != '.') {
-        return MBEDTLS_ERR_ASN1_INVALID_DATA;
+        ret = MBEDTLS_ERR_ASN1_INVALID_DATA;
+        goto error;
     }
     str_ptr++;
 
     ret = oid_parse_number(&component2, &str_ptr, str_bound);
     if (ret != 0) {
-        return ret;
+        goto error;
     }
     if ((component1 < 2) && (component2 > 39)) {
         /* Root nodes 0 and 1 may have up to 40 children, numbered 0-39 */
-        return MBEDTLS_ERR_ASN1_INVALID_DATA;
+        ret = MBEDTLS_ERR_ASN1_INVALID_DATA;
+        goto error;
     }
     if (str_ptr < str_bound && *str_ptr != '\0') {
         if (*str_ptr == '.') {
             str_ptr++;
         } else {
-            return MBEDTLS_ERR_ASN1_INVALID_DATA;
+            ret = MBEDTLS_ERR_ASN1_INVALID_DATA;
+            goto error;
         }
     }
 
     if ((UINT_MAX - component2) <= (component1 * 40)) {
-        return MBEDTLS_ERR_ASN1_INVALID_DATA;
+        ret = MBEDTLS_ERR_ASN1_INVALID_DATA;
+        goto error;
+    }
+    ret = oid_subidentifier_encode_into(&out_ptr, out_bound,
+                                        (component1 * 40) + component2);
+    if (ret != 0) {
+        goto error;
     }
-    encoded_len = oid_subidentifier_num_bytes((component1 * 40) + component2);
 
     while (str_ptr < str_bound && *str_ptr != '\0') {
-        oid_parse_number(&val, &str_ptr, str_bound);
+        ret = oid_parse_number(&val, &str_ptr, str_bound);
         if (ret != 0) {
-            return ret;
+            goto error;
         }
         if (str_ptr < str_bound && *str_ptr != '\0') {
             if (*str_ptr == '.') {
                 str_ptr++;
             } else {
-                return MBEDTLS_ERR_ASN1_INVALID_DATA;
+                ret = MBEDTLS_ERR_ASN1_INVALID_DATA;
+                goto error;
             }
         }
 
-        size_t num_bytes = oid_subidentifier_num_bytes(val);
-        if ((SIZE_MAX - encoded_len) <= num_bytes) {
-            return MBEDTLS_ERR_ASN1_INVALID_DATA;
-        }
-        encoded_len += num_bytes;
-    }
-
-    oid->p = mbedtls_calloc(encoded_len, 1);
-    if (oid->p == NULL) {
-        return MBEDTLS_ERR_ASN1_ALLOC_FAILED;
-    }
-    oid->len = encoded_len;
-
-    /* Second pass - now that we've allocated the buffer, go back to the
-     * start and encode */
-
-    str_ptr = oid_str;
-    unsigned char *out_ptr = oid->p;
-    unsigned char *out_bound = oid->p + oid->len;
-
-    /* No need to do validation this time, as we did it on the first pass */
-    oid_parse_number(&component1, &str_ptr, str_bound);
-    /* Skip past the '.' */
-    str_ptr++;
-    oid_parse_number(&component2, &str_ptr, str_bound);
-    /* Skip past the '.' */
-    str_ptr++;
-    ret = oid_subidentifier_encode_into(&out_ptr, out_bound,
-                                        (component1 * 40) + component2);
-    if (ret != 0) {
-        mbedtls_free(oid->p);
-        oid->p = NULL;
-        oid->len = 0;
-        return ret;
-    }
-    while (str_ptr < str_bound && *str_ptr != '\0') {
-        oid_parse_number(&val, &str_ptr, str_bound);
-        if (str_ptr < str_bound && *str_ptr == '.') {
-            /* Skip past the '.' */
-            str_ptr++;
-        }
-
         ret = oid_subidentifier_encode_into(&out_ptr, out_bound, val);
         if (ret != 0) {
-            mbedtls_free(oid->p);
-            oid->p = NULL;
-            oid->len = 0;
-            return ret;
+            goto error;
         }
     }
+
+    size_t encoded_len = out_ptr - oid->p;
+    unsigned char *minimum_mem = mbedtls_calloc(encoded_len, 1);
+    if (minimum_mem == NULL) {
+        ret = MBEDTLS_ERR_ASN1_ALLOC_FAILED;
+        goto error;
+    }
+    memcpy(minimum_mem, oid->p, encoded_len);
+    mbedtls_free(oid->p);
+    oid->p = minimum_mem;
+    oid->len = encoded_len;
+
     oid->tag = MBEDTLS_ASN1_OID;
 
     return 0;
+
+error:
+    mbedtls_free(oid->p);
+    oid->p = NULL;
+    oid->len = 0;
+    return ret;
 }
 
 #endif /* MBEDTLS_OID_C */

From 9643575d92440b8efc91cb60b7f0270e23f5fae8 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Wed, 26 Apr 2023 11:50:14 +0100
Subject: [PATCH 14/27] Limit OIDs to 128 components

The longest OID known by oid-info.com is 34 components[1], so 128
should be plenty and will limit the potential for attacks.

[1] http://oid-info.com/get/1.3.6.1.4.1.1248.1.1.2.1.3.21.69.112.115.111.110.32.83.116.121.108.117.115.32.80.114.111.32.52.57.48.48

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 include/mbedtls/oid.h            | 5 +++++
 library/oid.c                    | 2 +-
 tests/suites/test_suite_oid.data | 3 +++
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/include/mbedtls/oid.h b/include/mbedtls/oid.h
index b2f5dd196..1d73506dc 100644
--- a/include/mbedtls/oid.h
+++ b/include/mbedtls/oid.h
@@ -63,6 +63,11 @@
 #define MBEDTLS_OID_X509_EXT_FRESHEST_CRL                (1 << 14)
 #define MBEDTLS_OID_X509_EXT_NS_CERT_TYPE                (1 << 16)
 
+/*
+ * Maximum number of OID components allowed
+ */
+#define MBEDTLS_OID_MAX_COMPONENTS              128
+
 /*
  * Top level OID tuples
  */
diff --git a/library/oid.c b/library/oid.c
index 139a707c8..8da410380 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -963,7 +963,7 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
     /* Allocate maximum possible required memory:
      * There are (num_dots + 1) integer components, but the first 2 share the
      * same subidentifier, so we only need num_dots subidentifiers maximum. */
-    if (num_dots == 0 || (num_dots > SIZE_MAX / sizeof(unsigned int))) {
+    if (num_dots == 0 || (num_dots > MBEDTLS_OID_MAX_COMPONENTS - 1)) {
         return MBEDTLS_ERR_ASN1_INVALID_DATA;
     }
     size_t max_possible_bytes = num_dots * sizeof(unsigned int);
diff --git a/tests/suites/test_suite_oid.data b/tests/suites/test_suite_oid.data
index d4a7dea21..c5f13175b 100644
--- a/tests/suites/test_suite_oid.data
+++ b/tests/suites/test_suite_oid.data
@@ -158,3 +158,6 @@ oid_from_numeric_string:"1.2/3.4":MBEDTLS_ERR_ASN1_INVALID_DATA:""
 
 OID from numeric string - non-'.' separator between third and fourth
 oid_from_numeric_string:"1.2.3/4":MBEDTLS_ERR_ASN1_INVALID_DATA:""
+
+OID from numeric string - OID greater than max length (129 components)
+oid_from_numeric_string:"1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1":MBEDTLS_ERR_ASN1_INVALID_DATA:""

From b6ff8a2c4bf117d67500f04f346d77604214055e Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Wed, 26 Apr 2023 12:10:36 +0100
Subject: [PATCH 15/27] Add ChangeLog entry for string-to-OID parsing

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 ChangeLog.d/oid-parse-from-numeric-string.txt | 3 +++
 1 file changed, 3 insertions(+)
 create mode 100644 ChangeLog.d/oid-parse-from-numeric-string.txt

diff --git a/ChangeLog.d/oid-parse-from-numeric-string.txt b/ChangeLog.d/oid-parse-from-numeric-string.txt
new file mode 100644
index 000000000..459bedc83
--- /dev/null
+++ b/ChangeLog.d/oid-parse-from-numeric-string.txt
@@ -0,0 +1,3 @@
+Features
+   * Add a function mbedtls_oid_from_numeric_string to parse an OID from a
+     string to a DER-encoded mbedtls_asn1_buf.

From 57b5d22a9e6b9bae09fde67b794f34ab36e44199 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Wed, 31 May 2023 14:36:41 +0100
Subject: [PATCH 16/27] Reword ChangeLog entry for consistency

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 ChangeLog.d/oid-parse-from-numeric-string.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ChangeLog.d/oid-parse-from-numeric-string.txt b/ChangeLog.d/oid-parse-from-numeric-string.txt
index 459bedc83..82ed2fd71 100644
--- a/ChangeLog.d/oid-parse-from-numeric-string.txt
+++ b/ChangeLog.d/oid-parse-from-numeric-string.txt
@@ -1,3 +1,3 @@
 Features
-   * Add a function mbedtls_oid_from_numeric_string to parse an OID from a
+   * Add function mbedtls_oid_from_numeric_string() to parse an OID from a
      string to a DER-encoded mbedtls_asn1_buf.

From b97b689832d77464b63651fdabbec9d7bdd7dca0 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Wed, 31 May 2023 14:41:11 +0100
Subject: [PATCH 17/27] Reword function description slightly

Use of the term "dotted-decimal" improves clarity. Put a full-stop where
one should have been.

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 include/mbedtls/oid.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/mbedtls/oid.h b/include/mbedtls/oid.h
index 1d73506dc..5b75077ea 100644
--- a/include/mbedtls/oid.h
+++ b/include/mbedtls/oid.h
@@ -472,9 +472,9 @@ typedef struct mbedtls_oid_descriptor_t {
 int mbedtls_oid_get_numeric_string(char *buf, size_t size, const mbedtls_asn1_buf *oid);
 
 /**
- * \brief           Translate a string containing a numeric representation
- *                  of an ASN.1 OID into its encoded form
- *                  (e.g. "1.2.840.113549" into "\x2A\x86\x48\x86\xF7\x0D")
+ * \brief           Translate a string containing a dotted-decimal
+ *                  representation of an ASN.1 OID into its encoded form
+ *                  (e.g. "1.2.840.113549" into "\x2A\x86\x48\x86\xF7\x0D").
  *                  On success, this function allocates oid->buf from the
  *                  heap. It must be freed by the caller using mbedtls_free().
  *

From ada7d72447e996b31448af1d8a22fc7bbb8d2261 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Wed, 31 May 2023 14:49:56 +0100
Subject: [PATCH 18/27] Improve line spacing after variable declarations

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 library/oid.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/library/oid.c b/library/oid.c
index 8da410380..d2efbed1f 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -898,7 +898,9 @@ int mbedtls_oid_get_numeric_string(char *buf, size_t size,
 static int oid_parse_number(unsigned int *num, const char **p, const char *bound)
 {
     int ret = MBEDTLS_ERR_ASN1_INVALID_DATA;
+
     *num = 0;
+
     while (*p < bound && **p >= '0' && **p <= '9') {
         ret = 0;
         if (*num > (UINT_MAX / 10)) {
@@ -914,7 +916,9 @@ static int oid_parse_number(unsigned int *num, const char **p, const char *bound
 static size_t oid_subidentifier_num_bytes(unsigned int value)
 {
     size_t num_bytes = 1;
+
     value >>= 7;
+
     while (value != 0) {
         num_bytes++;
         value >>= 7;
@@ -927,6 +931,7 @@ static int oid_subidentifier_encode_into(unsigned char **p,
                                          unsigned int value)
 {
     size_t num_bytes = oid_subidentifier_num_bytes(value);
+
     if ((size_t) (bound - *p) < num_bytes) {
         return MBEDTLS_ERR_OID_BUF_TOO_SMALL;
     }
@@ -947,14 +952,13 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
                                     const char *oid_str, size_t size)
 {
     int ret = MBEDTLS_ERR_ASN1_INVALID_DATA;
-
     const char *str_ptr = oid_str;
     const char *str_bound = oid_str + size;
     unsigned int val = 0;
     unsigned int component1, component2;
-
     /* Count the number of dots to get a worst-case allocation size. */
     size_t num_dots = 0;
+
     for (size_t i = 0; (i < size) && (oid_str[i] != '\0'); i++) {
         if (oid_str[i] == '.') {
             num_dots++;

From 25d65e85274b4eb788be1dda8781625ec35dc4a9 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Wed, 31 May 2023 14:53:07 +0100
Subject: [PATCH 19/27] Refactor while loop for simplicity

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 library/oid.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/library/oid.c b/library/oid.c
index d2efbed1f..ea1e70bf0 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -915,14 +915,13 @@ static int oid_parse_number(unsigned int *num, const char **p, const char *bound
 
 static size_t oid_subidentifier_num_bytes(unsigned int value)
 {
-    size_t num_bytes = 1;
+    size_t num_bytes = 0;
 
-    value >>= 7;
-
-    while (value != 0) {
-        num_bytes++;
+    do {
         value >>= 7;
-    }
+        num_bytes++;
+    } while (value != 0);
+
     return num_bytes;
 }
 

From 6883358c16f2e369129753d3999bb345e57c3f29 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Wed, 31 May 2023 17:27:28 +0100
Subject: [PATCH 20/27] Hoist variable declarations to before goto

This should appease IAR, which does not like declarations in the middle
of goto sequences.

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 library/oid.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/library/oid.c b/library/oid.c
index ea1e70bf0..87e5d892f 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -957,6 +957,8 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
     unsigned int component1, component2;
     /* Count the number of dots to get a worst-case allocation size. */
     size_t num_dots = 0;
+    size_t encoded_len;
+    unsigned char *minimum_mem;
 
     for (size_t i = 0; (i < size) && (oid_str[i] != '\0'); i++) {
         if (oid_str[i] == '.') {
@@ -1040,8 +1042,8 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
         }
     }
 
-    size_t encoded_len = out_ptr - oid->p;
-    unsigned char *minimum_mem = mbedtls_calloc(encoded_len, 1);
+    encoded_len = out_ptr - oid->p;
+    minimum_mem = mbedtls_calloc(encoded_len, 1);
     if (minimum_mem == NULL) {
         ret = MBEDTLS_ERR_ASN1_ALLOC_FAILED;
         goto error;

From d1a203a382a65a458a5736525237525dc3ca9697 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Thu, 1 Jun 2023 15:02:15 +0100
Subject: [PATCH 21/27] Cosmetic fixes to doxygen comment

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 include/mbedtls/oid.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/mbedtls/oid.h b/include/mbedtls/oid.h
index 5b75077ea..da3d70ed5 100644
--- a/include/mbedtls/oid.h
+++ b/include/mbedtls/oid.h
@@ -478,12 +478,12 @@ int mbedtls_oid_get_numeric_string(char *buf, size_t size, const mbedtls_asn1_bu
  *                  On success, this function allocates oid->buf from the
  *                  heap. It must be freed by the caller using mbedtls_free().
  *
- * \param oid       mbedtls_asn1_buf to populate with the DER-encoded OID
+ * \param oid       #mbedtls_asn1_buf to populate with the DER-encoded OID
  * \param oid_str   string representation of the OID to parse
  * \param size      length of the OID string
  *
  * \return          0 if successful
- * \return          #MBEDTLS_ERR_ASN1_INVALID_DATA if oid_str does not
+ * \return          #MBEDTLS_ERR_ASN1_INVALID_DATA if \p oid_str does not
  *                  represent a valid OID
  * \return          #MBEDTLS_ERR_ASN1_ALLOC_FAILED if the function fails to
  *                  allocate oid->buf

From 017139751a81895faa33ce59f1d1ff5ced5b741b Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Thu, 1 Jun 2023 15:04:20 +0100
Subject: [PATCH 22/27] Change behaviour away from NUL-terminated strings

Instead, require the length of the string to be passed. This is more
useful for our use-case, as it is likely we will parse OIDs from the
middle of strings.

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 include/mbedtls/oid.h | 5 +++--
 library/oid.c         | 8 ++++----
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/include/mbedtls/oid.h b/include/mbedtls/oid.h
index da3d70ed5..68ae72317 100644
--- a/include/mbedtls/oid.h
+++ b/include/mbedtls/oid.h
@@ -479,8 +479,9 @@ int mbedtls_oid_get_numeric_string(char *buf, size_t size, const mbedtls_asn1_bu
  *                  heap. It must be freed by the caller using mbedtls_free().
  *
  * \param oid       #mbedtls_asn1_buf to populate with the DER-encoded OID
- * \param oid_str   string representation of the OID to parse
- * \param size      length of the OID string
+ * \param oid_str   string representation of the OID to parse, not
+ *                  NUL-terminated
+ * \param size      length of the OID string, not including any NUL terminator
  *
  * \return          0 if successful
  * \return          #MBEDTLS_ERR_ASN1_INVALID_DATA if \p oid_str does not
diff --git a/library/oid.c b/library/oid.c
index 87e5d892f..312a6375b 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -960,7 +960,7 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
     size_t encoded_len;
     unsigned char *minimum_mem;
 
-    for (size_t i = 0; (i < size) && (oid_str[i] != '\0'); i++) {
+    for (size_t i = 0; i < size; i++) {
         if (oid_str[i] == '.') {
             num_dots++;
         }
@@ -1003,7 +1003,7 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
         ret = MBEDTLS_ERR_ASN1_INVALID_DATA;
         goto error;
     }
-    if (str_ptr < str_bound && *str_ptr != '\0') {
+    if (str_ptr < str_bound) {
         if (*str_ptr == '.') {
             str_ptr++;
         } else {
@@ -1022,12 +1022,12 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
         goto error;
     }
 
-    while (str_ptr < str_bound && *str_ptr != '\0') {
+    while (str_ptr < str_bound) {
         ret = oid_parse_number(&val, &str_ptr, str_bound);
         if (ret != 0) {
             goto error;
         }
-        if (str_ptr < str_bound && *str_ptr != '\0') {
+        if (str_ptr < str_bound) {
             if (*str_ptr == '.') {
                 str_ptr++;
             } else {

From 5d074168f38e6ee87c34087343f7a7abc9ac5be4 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Thu, 1 Jun 2023 15:09:27 +0100
Subject: [PATCH 23/27] Rearrange declarations for readability

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 library/oid.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/library/oid.c b/library/oid.c
index 312a6375b..cda87a9dc 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -955,11 +955,11 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
     const char *str_bound = oid_str + size;
     unsigned int val = 0;
     unsigned int component1, component2;
-    /* Count the number of dots to get a worst-case allocation size. */
-    size_t num_dots = 0;
     size_t encoded_len;
     unsigned char *minimum_mem;
 
+    /* Count the number of dots to get a worst-case allocation size. */
+    size_t num_dots = 0;
     for (size_t i = 0; i < size; i++) {
         if (oid_str[i] == '.') {
             num_dots++;

From 45d5e2dc1a5c12e732f8b6c2ceadcc1b99130c13 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Thu, 1 Jun 2023 15:10:33 +0100
Subject: [PATCH 24/27] Rename minimum_mem to resized_mem

This new name is clearer about its purpose.

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 library/oid.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/library/oid.c b/library/oid.c
index cda87a9dc..02e41363e 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -956,7 +956,7 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
     unsigned int val = 0;
     unsigned int component1, component2;
     size_t encoded_len;
-    unsigned char *minimum_mem;
+    unsigned char *resized_mem;
 
     /* Count the number of dots to get a worst-case allocation size. */
     size_t num_dots = 0;
@@ -1043,14 +1043,14 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
     }
 
     encoded_len = out_ptr - oid->p;
-    minimum_mem = mbedtls_calloc(encoded_len, 1);
-    if (minimum_mem == NULL) {
+    resized_mem = mbedtls_calloc(encoded_len, 1);
+    if (resized_mem == NULL) {
         ret = MBEDTLS_ERR_ASN1_ALLOC_FAILED;
         goto error;
     }
-    memcpy(minimum_mem, oid->p, encoded_len);
+    memcpy(resized_mem, oid->p, encoded_len);
     mbedtls_free(oid->p);
-    oid->p = minimum_mem;
+    oid->p = resized_mem;
     oid->len = encoded_len;
 
     oid->tag = MBEDTLS_ASN1_OID;

From bf95e9a0584c54bf7535c76608de31b0e52d29b2 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Thu, 1 Jun 2023 15:33:15 +0100
Subject: [PATCH 25/27] Reword description and change NUL to null

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 include/mbedtls/oid.h | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/include/mbedtls/oid.h b/include/mbedtls/oid.h
index 68ae72317..7fa014139 100644
--- a/include/mbedtls/oid.h
+++ b/include/mbedtls/oid.h
@@ -479,9 +479,8 @@ int mbedtls_oid_get_numeric_string(char *buf, size_t size, const mbedtls_asn1_bu
  *                  heap. It must be freed by the caller using mbedtls_free().
  *
  * \param oid       #mbedtls_asn1_buf to populate with the DER-encoded OID
- * \param oid_str   string representation of the OID to parse, not
- *                  NUL-terminated
- * \param size      length of the OID string, not including any NUL terminator
+ * \param oid_str   string representation of the OID to parse
+ * \param size      length of the OID string, not including any null terminator
  *
  * \return          0 if successful
  * \return          #MBEDTLS_ERR_ASN1_INVALID_DATA if \p oid_str does not

From 02127ab02245936cb4869d8e2ed3b3fc378ef32b Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Fri, 2 Jun 2023 14:50:35 +0100
Subject: [PATCH 26/27] Allow subidentifiers of size UINT_MAX

Make overflow check more accurate and add testcases

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 library/oid.c                    | 2 +-
 tests/suites/test_suite_oid.data | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/library/oid.c b/library/oid.c
index 02e41363e..b13c76b1e 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -1012,7 +1012,7 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
         }
     }
 
-    if ((UINT_MAX - component2) <= (component1 * 40)) {
+    if (component2 > (UINT_MAX - (component1 * 40))) {
         ret = MBEDTLS_ERR_ASN1_INVALID_DATA;
         goto error;
     }
diff --git a/tests/suites/test_suite_oid.data b/tests/suites/test_suite_oid.data
index c5f13175b..1435507f6 100644
--- a/tests/suites/test_suite_oid.data
+++ b/tests/suites/test_suite_oid.data
@@ -161,3 +161,9 @@ oid_from_numeric_string:"1.2.3/4":MBEDTLS_ERR_ASN1_INVALID_DATA:""
 
 OID from numeric string - OID greater than max length (129 components)
 oid_from_numeric_string:"1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1.2.3.4.5.6.7.8.1":MBEDTLS_ERR_ASN1_INVALID_DATA:""
+
+OID from numeric string - OID with maximum subidentifier
+oid_from_numeric_string:"2.4294967215":0:"8FFFFFFF7F"
+
+OID from numeric string - OID with overflowing subidentifier
+oid_from_numeric_string:"2.4294967216":MBEDTLS_ERR_ASN1_INVALID_DATA:""

From 62e7fae1090544357bcfaf209b9d87f8f827bfeb Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Fri, 2 Jun 2023 15:32:20 +0100
Subject: [PATCH 27/27] Fix bug in calculation of maximum possible bytes

Each DER-encoded OID byte can only store 7 bits of actual data, so take
account of that.

Calculate the number of bytes required as:

number_of_bytes = ceil(subidentifier_size * 8 / 7)

Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 library/oid.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/library/oid.c b/library/oid.c
index b13c76b1e..88165d312 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -971,7 +971,14 @@ int mbedtls_oid_from_numeric_string(mbedtls_asn1_buf *oid,
     if (num_dots == 0 || (num_dots > MBEDTLS_OID_MAX_COMPONENTS - 1)) {
         return MBEDTLS_ERR_ASN1_INVALID_DATA;
     }
-    size_t max_possible_bytes = num_dots * sizeof(unsigned int);
+    /* Each byte can store 7 bits, calculate number of bytes for a
+     * subidentifier:
+     *
+     * bytes = ceil(subidentifer_size * 8 / 7)
+     */
+    size_t bytes_per_subidentifier = (((sizeof(unsigned int) * 8) - 1) / 7)
+                                     + 1;
+    size_t max_possible_bytes = num_dots * bytes_per_subidentifier;
     oid->p = mbedtls_calloc(max_possible_bytes, 1);
     if (oid->p == NULL) {
         return MBEDTLS_ERR_ASN1_ALLOC_FAILED;