ROS3: (feature) Temporary security credentials (#3030)

- Implemented support for AWS temporary security credentials.
  For this kind of credentials also a session/security token
  should be included in the request by adding the
  x-amz-security-token header.

Co-authored-by: Larry Knox <lrknox@hdfgroup.org>
Co-authored-by: Jordan Henderson <jhenderson@hdfgroup.org>
Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>

4 files changed, 468 insertions, 36 deletions

diff --git a/src/H5FDros3.c b/src/H5FDros3.c
index 3628185e..be35abc 100644
--- a/src/H5FDros3.c
+++ b/src/H5FDros3.c
@@ -47,6 +47,10 @@
  */
 static hid_t H5FD_ROS3_g = 0;
 
+/* Session/security token property name
+ */
+#define ROS3_TOKEN_PROP_NAME "ros3_token_prop"
+
 #if ROS3_STATS
 
 /* arbitrarily large value, such that any reasonable size read will be "less"
@@ -225,6 +229,11 @@ static herr_t  H5FD__ros3_truncate(H5FD_t *_file, hid_t dxpl_id, hbool_t closing
 
 static herr_t H5FD__ros3_validate_config(const H5FD_ros3_fapl_t *fa);
 
+static herr_t H5FD__ros3_str_token_copy(const char *name, size_t size, void *_value);
+static int    H5FD__ros3_str_token_cmp(const void *_value1, const void *_value2, size_t size);
+static herr_t H5FD__ros3_str_token_close(const char *name, size_t size, void *_value);
+static herr_t H5FD__ros3_str_token_delete(hid_t prop_id, const char *name, size_t size, void *_value);
+
 static const H5FD_class_t H5FD_ros3_g = {
     H5FD_CLASS_VERSION,       /* struct version       */
     H5FD_ROS3_VALUE,          /* value                */
@@ -566,6 +575,257 @@ H5FD__ros3_fapl_free(void *_fa)
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* end H5FD__ros3_fapl_free() */
 
+/*-------------------------------------------------------------------------
+ * Function:    H5Pget_fapl_ros3_token
+ *
+ * Purpose:     Returns session/security token of the ros3 file access
+ *              property list though the function arguments.
+ *
+ * Return:      Success:        Non-negative
+ *
+ *              Failure:        Negative
+ *
+ * Programmer:  Jan-Willem Blokland
+ *              2023-05-26
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pget_fapl_ros3_token(hid_t fapl_id, size_t size, char *token_dst /*out*/)
+{
+    H5P_genplist_t *plist = NULL;
+    char           *token_src;
+    htri_t          token_exists;
+    size_t          tokenlen  = 0;
+    herr_t          ret_value = SUCCEED;
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE3("e", "izx", fapl_id, size, token_dst);
+
+#if ROS3_DEBUG
+    HDfprintf(stdout, "H5Pget_fapl_ros3_token() called.\n");
+#endif
+
+    if (size == 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "size cannot be zero.")
+    if (token_dst == NULL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "token_dst is NULL")
+
+    if (NULL == (plist = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
+        HGOTO_ERROR(H5E_PLIST, H5E_BADTYPE, FAIL, "not a file access property list")
+    if (H5FD_ROS3 != H5P_peek_driver(plist))
+        HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "incorrect VFL driver")
+    if ((token_exists = H5P_exist_plist(plist, ROS3_TOKEN_PROP_NAME)) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "failed to check if property token exists in plist")
+    if (token_exists) {
+        if (H5P_get(plist, ROS3_TOKEN_PROP_NAME, &token_src) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "unable to get token value")
+    }
+
+    /* Copy the token data out */
+    tokenlen = HDstrlen(token_src);
+    if (size <= tokenlen) {
+        tokenlen = size - 1;
+    }
+    H5MM_memcpy(token_dst, token_src, sizeof(char) * tokenlen);
+    token_dst[tokenlen] = '\0';
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Pget_fapl_ros3_token() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5FD__ros3_str_token_copy()
+ *
+ * Purpose:     Create a copy of the token string.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ * Programmer:  Jan-Willem Blokland
+ *              2023-05-26
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5FD__ros3_str_token_copy(const char H5_ATTR_UNUSED *name, size_t H5_ATTR_UNUSED size, void *_value)
+{
+    char **value     = (char **)_value;
+    herr_t ret_value = SUCCEED;
+
+    FUNC_ENTER_PACKAGE
+
+#if ROS3_DEBUG
+    HDfprintf(stdout, "H5FD__ros3_str_token_copy() called.\n");
+#endif
+
+    if (*value)
+        if (NULL == (*value = HDstrdup(*value)))
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "can't copy string property token")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* H5FD__ros3_str_token_copy() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5FD__ros3_str_token_cmp()
+ *
+ * Purpose:     Compares two token strings with each other.
+ *
+ * Return:
+ *     - Equivalent:     0
+ *     - Not Equivalent: non-zero value
+ *
+ * Programmer:  Jan-Willem Blokland
+ *              2023-05-26
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+H5FD__ros3_str_token_cmp(const void *_value1, const void *_value2, size_t H5_ATTR_UNUSED size)
+{
+    char *const *value1    = (char *const *)_value1;
+    char *const *value2    = (char *const *)_value2;
+    int          ret_value = SUCCEED;
+
+    FUNC_ENTER_PACKAGE_NOERR
+
+    if (*value1) {
+        if (*value2)
+            ret_value = HDstrcmp(*value1, *value2);
+        else
+            ret_value = 1;
+    }
+    else {
+        if (*value2)
+            ret_value = -1;
+        else
+            ret_value = 0;
+    }
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5FD__ros3_str_token_cmp */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5FD__ros3_str_token_close()
+ *
+ * Purpose:     Closes/frees the memory associated to the token string.
+ *              Currently, it is an empty implementation since there no
+ *              additional treatment needed for this property.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ * Programmer:  Jan-Willem Blokland
+ *              2023-05-26
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5FD__ros3_str_token_close(const char H5_ATTR_UNUSED *name, size_t H5_ATTR_UNUSED size, void *_value)
+{
+    char **value     = (char **)_value;
+    herr_t ret_value = SUCCEED;
+
+    FUNC_ENTER_PACKAGE_NOERR
+
+    if (*value)
+        free(*value);
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5FD__ros3_str_token_close */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5FD__ros3_str_token_delete()
+ *
+ * Purpose:     Deletes the property token from the property list and frees
+ *              the memory associated to the token string.
+ *              Currently, it is an empty implementation since there no
+ *              additional treatment needed for this property.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ * Programmer:  Jan-Willem Blokland
+ *              2023-05-26
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5FD__ros3_str_token_delete(hid_t H5_ATTR_UNUSED prop_id, const char H5_ATTR_UNUSED *name,
+                            size_t H5_ATTR_UNUSED size, void *_value)
+{
+    char **value     = (char **)_value;
+    herr_t ret_value = SUCCEED;
+
+    FUNC_ENTER_PACKAGE_NOERR
+
+    if (*value)
+        free(*value);
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5FD__ros3_str_token_delete */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Pset_fapl_ros3_token()
+ *
+ * Purpose:     Modify the file access property list to use the H5FD_ROS3
+ *              driver defined in this source file by adding or
+ *              modifying the session/security token property.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ * Programmer:  Jan-Willem Blokland
+ *              2023-05-26
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pset_fapl_ros3_token(hid_t fapl_id, const char *token)
+{
+    H5P_genplist_t *plist = NULL;
+    char           *token_src;
+    htri_t          token_exists;
+    herr_t          ret_value = SUCCEED;
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE2("e", "i*s", fapl_id, token);
+
+#if ROS3_DEBUG
+    HDfprintf(stdout, "H5Pset_fapl_ros3_token() called.\n");
+#endif
+
+    if (fapl_id == H5P_DEFAULT)
+        HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "can't set values in default property list")
+    if (NULL == (plist = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
+        HGOTO_ERROR(H5E_PLIST, H5E_BADTYPE, FAIL, "not a file access property list")
+    if (H5FD_ROS3 != H5P_peek_driver(plist))
+        HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "incorrect VFL driver")
+    if (HDstrlen(token) > H5FD_ROS3_MAX_SECRET_TOK_LEN)
+        HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL,
+                    "specified token exceeds the internally specified maximum string length")
+
+    if ((token_exists = H5P_exist_plist(plist, ROS3_TOKEN_PROP_NAME)) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "failed to check if property token exists in plist")
+
+    if (token_exists) {
+        if (H5P_get(plist, ROS3_TOKEN_PROP_NAME, &token_src) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "unable to get token value")
+
+        memcpy(token_src, token, HDstrlen(token) + 1);
+    }
+    else {
+        token_src = (char *)malloc(sizeof(char) * (H5FD_ROS3_MAX_SECRET_TOK_LEN + 1));
+        if (token_src == NULL)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "cannot make space for token_src variable.");
+        memcpy(token_src, token, HDstrlen(token) + 1);
+        if (H5P_insert(plist, ROS3_TOKEN_PROP_NAME, sizeof(char *), &token_src, NULL, NULL, NULL, NULL,
+                       H5FD__ros3_str_token_delete, H5FD__ros3_str_token_copy, H5FD__ros3_str_token_cmp,
+                       H5FD__ros3_str_token_close) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTREGISTER, FAIL, "unable to register property in plist")
+    }
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Pset_fapl_ros3_token() */
+
 #if ROS3_STATS
 /*----------------------------------------------------------------------------
  *
@@ -654,6 +914,9 @@ H5FD__ros3_open(const char *url, unsigned flags, hid_t fapl_id, haddr_t maxaddr)
     unsigned char    signing_key[SHA256_DIGEST_LENGTH];
     s3r_t           *handle = NULL;
     H5FD_ros3_fapl_t fa;
+    H5P_genplist_t  *plist = NULL;
+    htri_t           token_exists;
+    char            *token;
     H5FD_t          *ret_value = NULL;
 
     FUNC_ENTER_PACKAGE
@@ -681,6 +944,16 @@ H5FD__ros3_open(const char *url, unsigned flags, hid_t fapl_id, haddr_t maxaddr)
     if (CURLE_OK != curl_global_init(CURL_GLOBAL_DEFAULT))
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "unable to initialize curl global (placeholder flags)")
 
+    /* Session/security token */
+    if (NULL == (plist = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
+        HGOTO_ERROR(H5E_PLIST, H5E_BADTYPE, NULL, "not a file access property list")
+    if ((token_exists = H5P_exist_plist(plist, ROS3_TOKEN_PROP_NAME)) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "failed to check if property token exists in plist")
+    if (token_exists) {
+        if (H5P_get(plist, ROS3_TOKEN_PROP_NAME, &token) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "unable to get token value")
+    }
+
     /* open file; procedure depends on whether or not the fapl instructs to
      * authenticate requests or not.
      */
@@ -697,11 +970,15 @@ H5FD__ros3_open(const char *url, unsigned flags, hid_t fapl_id, haddr_t maxaddr)
                                              (const char *)fa.aws_region, (const char *)iso8601now))
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "problem while computing signing key")
 
-        handle = H5FD_s3comms_s3r_open(url, (const char *)fa.aws_region, (const char *)fa.secret_id,
-                                       (const unsigned char *)signing_key);
+        if (token_exists)
+            handle = H5FD_s3comms_s3r_open(url, (const char *)fa.aws_region, (const char *)fa.secret_id,
+                                           (const unsigned char *)signing_key, (const char *)token);
+        else
+            handle = H5FD_s3comms_s3r_open(url, (const char *)fa.aws_region, (const char *)fa.secret_id,
+                                           (const unsigned char *)signing_key, "");
     }
     else
-        handle = H5FD_s3comms_s3r_open(url, NULL, NULL, NULL);
+        handle = H5FD_s3comms_s3r_open(url, NULL, NULL, NULL, NULL);
 
     if (handle == NULL)
         /* If we want to check CURL's say on the matter in a controlled
diff --git a/src/H5FDros3.h b/src/H5FDros3.h
index f84b1a4..0f2f315 100644
--- a/src/H5FDros3.h
+++ b/src/H5FDros3.h
@@ -70,12 +70,63 @@
  *
  ****************************************************************************/
 
+/**
+ * \def H5FD_CURR_ROS3_FAPL_T_VERSION
+ * The version number of the H5FD_ros3_fapl_t configuration
+ * structure for the $H5FD_ROS3 driver.
+ */
 #define H5FD_CURR_ROS3_FAPL_T_VERSION 1
 
-#define H5FD_ROS3_MAX_REGION_LEN     32
-#define H5FD_ROS3_MAX_SECRET_ID_LEN  128
+/**
+ * \def H5FD_ROS3_MAX_REGION_LEN
+ * Maximum string length for specifying the region of the S3 bucket.
+ */
+#define H5FD_ROS3_MAX_REGION_LEN 32
+/**
+ * \def H5FD_ROS3_MAX_SECRET_ID_LEN
+ * Maximum string length for specifying the security ID.
+ */
+#define H5FD_ROS3_MAX_SECRET_ID_LEN 128
+/**
+ * \def H5FD_ROS3_MAX_SECRET_KEY_LEN
+ * Maximum string length for specifying the security key.
+ */
 #define H5FD_ROS3_MAX_SECRET_KEY_LEN 128
+/**
+ * \def H5FD_ROS3_MAX_SECRET_TOK_LEN
+ * Maximum string length for specifying the session/security token.
+ */
+#define H5FD_ROS3_MAX_SECRET_TOK_LEN 1024
 
+/**
+ *\struct H5FD_ros3_fapl_t
+ * \brief Configuration structure for H5Pset_fapl_ros3() / H5Pget_fapl_ros3().
+ *
+ * \details H5FD_ros_fapl_t is a public structure that is used to pass
+ *          configuration data to the #H5FD_ROS3 driver via a File Access
+ *          Property List. A pointer to an instance of this structure is
+ *          a parameter to H5Pset_fapl_ros3() and H5Pget_fapl_ros3().
+ *
+ * \var int32_t H5FD_ros3_fapl_t::version
+ *      Version number of the H5FD_ros3_fapl_t structure. Any instance passed
+ *      to H5Pset_fapl_ros3() / H5Pget_fapl_ros3() must have a recognized version
+ *      number or an error will be raised. Currently, this field should be set
+ *      to #H5FD_CURR_ROS3_FAPL_T_VERSION.
+ *
+ * \var hbool_t H5FD_ros3_fapl_t::authenticate
+ *      A boolean which specifies if security credentials should be used for
+ *      accessing a S3 bucket.
+ *
+ * \var char H5FD_ros3_fapl_t::aws_region[H5FD_ROS3_MAX_REGION_LEN + 1]
+ *      A string which specifies the AWS region of the S3 bucket.
+ *
+ * \var char H5FD_ros3_fapl_t::secret_id[H5FD_ROS3_MAX_SECRET_ID_LEN + 1]
+ *      A string which specifies the security ID.
+ *
+ * \var char H5FD_ros3_fapl_t::secret_key[H5FD_ROS3_MAX_SECRET_KEY_LEN + 1]
+ *      A string which specifies the security key.
+ *
+ */
 typedef struct H5FD_ros3_fapl_t {
     int32_t version;
     hbool_t authenticate;
@@ -88,22 +139,72 @@ typedef struct H5FD_ros3_fapl_t {
 extern "C" {
 #endif
 
+/**
+ * \brief Internal routine to initialize #H5FD_ROS3 driver. Not meant to be
+ *        called directly by an HDF5 application.
+ */
 H5_DLL hid_t H5FD_ros3_init(void);
 
 /**
  * \ingroup FAPL
  *
- * \todo Add missing documentation
+ * \brief Queries a File Access Property List for #H5FD_ROS3 file driver properties.
+ *
+ * \fapl_id
+ * \param[out] fa_out Pointer to #H5FD_ROS3 driver configuration structure.
+ * \returns \herr_t
  */
 H5_DLL herr_t H5Pget_fapl_ros3(hid_t fapl_id, H5FD_ros3_fapl_t *fa_out);
 
 /**
  * \ingroup FAPL
  *
- * \todo Add missing documentation
+ * \brief Modifies the specified File Access Property List to use the #H5FD_ROS3 driver.
+ *
+ * \fapl_id
+ * \param[in] fa Pointer to #H5FD_ROS3 driver configuration structure.
+ * \returns \herr_t
  */
 H5_DLL herr_t H5Pset_fapl_ros3(hid_t fapl_id, const H5FD_ros3_fapl_t *fa);
 
+/**
+ * \ingroup FAPL
+ *
+ * \brief Queries a File Access Property List for #H5FD_ROS3 file driver session/security
+ *        token.
+ *
+ * \fapl_id
+ * \param[in] size Size of the provided char array for storing the session/security token.
+ * \param[out] token Session/security token.
+ * \returns \herr_t
+ *
+ * \since 1.14.2
+ */
+H5_DLL herr_t H5Pget_fapl_ros3_token(hid_t fapl_id, size_t size, char *token);
+
+/**
+ * \ingroup FAPL
+ *
+ * \brief Modifies the specified File Access Property List to use the #H5FD_ROS3 driver
+ *        by adding the specified session/security token.
+ *
+ * \fapl_id
+ * \param[in] token Session/security token.
+ * \returns \herr_t
+ *
+ * \details H5Pset_fapl_ros3_token() modifies an existing File Access Property List which
+ *          is used by #H5FD_ROS3 driver by adding or updating the session/security token
+ *          of the property list. Be aware, to set the token first you need to create
+ *          a proper File Access Property List using H5Pset_fapl_ros() and use this list
+ *          as input argument of the function H5Pset_fapl_ros3_token().
+ *
+ *          Note, the session token is only needed when you want to access a S3 bucket
+ *          using temporary security credentials.
+ *
+ * \since 1.14.2
+ */
+H5_DLL herr_t H5Pset_fapl_ros3_token(hid_t fapl_id, const char *token);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/H5FDs3comms.c b/src/H5FDs3comms.c
index 74a4bbc..10b3ff2 100644
--- a/src/H5FDs3comms.c
+++ b/src/H5FDs3comms.c
@@ -39,6 +39,7 @@
 #include "H5Eprivate.h"  /* error handling    */
 #include "H5MMprivate.h" /* memory management */
 #include "H5FDs3comms.h" /* S3 Communications */
+#include "H5FDros3.h"    /* ros3 file driver  */
 
 /****************/
 /* Local Macros */
@@ -775,6 +776,7 @@ H5FD_s3comms_s3r_close(s3r_t *handle)
     H5MM_xfree(handle->secret_id);
     H5MM_xfree(handle->region);
     H5MM_xfree(handle->signing_key);
+    H5MM_xfree(handle->token);
 
     assert(handle->httpverb != NULL);
     H5MM_xfree(handle->httpverb);
@@ -1001,7 +1003,8 @@ done:
  *----------------------------------------------------------------------------
  */
 s3r_t *
-H5FD_s3comms_s3r_open(const char *url, const char *region, const char *id, const unsigned char *signing_key)
+H5FD_s3comms_s3r_open(const char *url, const char *region, const char *id, const unsigned char *signing_key,
+                      const char *token)
 {
     size_t        tmplen    = 0;
     CURL         *curlh     = NULL;
@@ -1035,13 +1038,15 @@ H5FD_s3comms_s3r_open(const char *url, const char *region, const char *id, const
     handle->region      = NULL;
     handle->secret_id   = NULL;
     handle->signing_key = NULL;
+    handle->token       = NULL;
     handle->httpverb    = NULL;
 
     /*************************************
      * RECORD AUTHENTICATION INFORMATION *
      *************************************/
 
-    if ((region != NULL && *region != '\0') || (id != NULL && *id != '\0') || (signing_key != NULL)) {
+    if ((region != NULL && *region != '\0') || (id != NULL && *id != '\0') || (signing_key != NULL) ||
+        (token != NULL)) {
 
         /* if one exists, all three must exist */
         if (region == NULL || region[0] == '\0')
@@ -1050,6 +1055,8 @@ H5FD_s3comms_s3r_open(const char *url, const char *region, const char *id, const
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "secret id cannot be null.");
         if (signing_key == NULL)
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "signing key cannot be null.");
+        if (token == NULL)
+            HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "token cannot be null.");
 
         /* copy strings */
         tmplen         = HDstrlen(region) + 1;
@@ -1069,6 +1076,12 @@ H5FD_s3comms_s3r_open(const char *url, const char *region, const char *id, const
         if (handle->signing_key == NULL)
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "could not malloc space for handle key copy.");
         H5MM_memcpy(handle->signing_key, signing_key, tmplen);
+
+        tmplen        = HDstrlen(token) + 1;
+        handle->token = (char *)H5MM_malloc(sizeof(char) * tmplen);
+        if (handle->token == NULL)
+            HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "could not malloc space for handle token copy.");
+        H5MM_memcpy(handle->token, token, tmplen);
     } /* if authentication information provided */
 
     /************************
@@ -1130,6 +1143,7 @@ done:
             H5MM_xfree(handle->region);
             H5MM_xfree(handle->secret_id);
             H5MM_xfree(handle->signing_key);
+            H5MM_xfree(handle->token);
             if (handle->httpverb != NULL)
                 H5MM_xfree(handle->httpverb);
             H5MM_xfree(handle);
@@ -1190,8 +1204,11 @@ H5FD_s3comms_s3r_read(s3r_t *handle, haddr_t offset, size_t len, void *dest)
     hrb_t             *request       = NULL;
     int                ret           = 0; /* working variable to check  */
                                           /* return value of HDsnprintf  */
-    struct s3r_datastruct *sds       = NULL;
-    herr_t                 ret_value = SUCCEED;
+    char                  *authorization  = NULL;
+    char                  *buffer1        = NULL;
+    char                  *signed_headers = NULL;
+    struct s3r_datastruct *sds            = NULL;
+    herr_t                 ret_value      = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
 
@@ -1284,23 +1301,31 @@ H5FD_s3comms_s3r_read(s3r_t *handle, haddr_t offset, size_t len, void *dest)
     else {
         /* authenticate request
          */
-        char authorization[512 + 1];
-        /*   512 := approximate max length...
-         *    67 <len("AWS4-HMAC-SHA256 Credential=///s3/aws4_request,"
-         *           "SignedHeaders=,Signature=")>
-         * +   8 <yyyyMMDD>
-         * +  64 <hex(sha256())>
-         * + 128 <max? len(secret_id)>
-         * +  20 <max? len(region)>
-         * + 128 <max? len(signed_headers)>
+        authorization = (char *)H5MM_malloc(512 + H5FD_ROS3_MAX_SECRET_TOK_LEN + 1);
+        if (authorization == NULL)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "cannot make space for authorization variable.");
+        /*   2048 := approximate max length...
+         *     67 <len("AWS4-HMAC-SHA256 Credential=///s3/aws4_request,"
+         *             "SignedHeaders=,Signature=")>
+         * +    8 <yyyyMMDD>
+         * +   64 <hex(sha256())>
+         * +  128 <max? len(secret_id)>
+         * +   20 <max? len(region)>
+         * +  128 <max? len(signed_headers)>
+         * + 1024 <max? len(session_token)>
          */
-        char buffer1[512 + 1]; /* -> Canonical Request -> Signature */
         char buffer2[256 + 1]; /* -> String To Sign -> Credential */
         char iso8601now[ISO8601_SIZE];
-        char signed_headers[48 + 1];
+        buffer1 = (char *)H5MM_malloc(512 + H5FD_ROS3_MAX_SECRET_TOK_LEN +
+                                      1); /* -> Canonical Request -> Signature */
+        if (buffer1 == NULL)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "cannot make space for buffer1 variable.");
+        signed_headers = (char *)H5MM_malloc(48 + H5FD_ROS3_MAX_SECRET_KEY_LEN + 1);
+        if (signed_headers == NULL)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "cannot make space for signed_headers variable.");
         /* should be large enough for nominal listing:
-         * "host;range;x-amz-content-sha256;x-amz-date"
-         * + '\0', with "range;" possibly absent
+         * "host;range;x-amz-content-sha256;x-amz-date;x-amz-security-token"
+         * + '\0', with "range;" and/or "x-amz-security-token" possibly absent
          */
 
         /* zero start of strings */
@@ -1318,6 +1343,8 @@ H5FD_s3comms_s3r_read(s3r_t *handle, haddr_t offset, size_t len, void *dest)
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "handle must have non-null secret_id.");
         if (handle->signing_key == NULL)
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "handle must have non-null signing_key.");
+        if (handle->token == NULL)
+            HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "handle must have non-null token.");
         if (handle->httpverb == NULL)
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "handle must have non-null httpverb.");
         if (handle->purl->host == NULL)
@@ -1349,6 +1376,15 @@ H5FD_s3comms_s3r_read(s3r_t *handle, haddr_t offset, size_t len, void *dest)
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "problem building headers list.");
         assert(headers->magic == S3COMMS_HRB_NODE_MAGIC);
 
+        if (HDstrlen((const char *)handle->token) > 0) {
+            if (FAIL ==
+                H5FD_s3comms_hrb_node_set(&headers, "x-amz-security-token", (const char *)handle->token))
+                HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unable to set x-amz-security-token header")
+            if (headers == NULL)
+                HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "problem building headers list.");
+            assert(headers->magic == S3COMMS_HRB_NODE_MAGIC);
+        }
+
         if (rangebytesstr != NULL) {
             if (FAIL == H5FD_s3comms_hrb_node_set(&headers, "Range", rangebytesstr))
                 HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unable to set range header")
@@ -1368,8 +1404,11 @@ H5FD_s3comms_s3r_read(s3r_t *handle, haddr_t offset, size_t len, void *dest)
         /**** COMPUTE AUTHORIZATION ****/
 
         /* buffer1 -> canonical request */
-        if (FAIL == H5FD_s3comms_aws_canonical_request(buffer1, 512, signed_headers, 48, request))
+        if (FAIL == H5FD_s3comms_aws_canonical_request(buffer1, 512 + H5FD_ROS3_MAX_SECRET_TOK_LEN,
+                                                       signed_headers, 48 + H5FD_ROS3_MAX_SECRET_TOK_LEN,
+                                                       request)) {
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "bad canonical request");
+        }
         /* buffer2->string-to-sign */
         if (FAIL == H5FD_s3comms_tostringtosign(buffer2, buffer1, iso8601now, handle->region))
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "bad string-to-sign");
@@ -1383,9 +1422,10 @@ H5FD_s3comms_s3r_read(s3r_t *handle, haddr_t offset, size_t len, void *dest)
         if (ret == 0 || ret >= S3COMMS_MAX_CREDENTIAL_SIZE)
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unable to format aws4 credential string");
 
-        ret = HDsnprintf(authorization, 512, "AWS4-HMAC-SHA256 Credential=%s,SignedHeaders=%s,Signature=%s",
-                         buffer2, signed_headers, buffer1);
-        if (ret <= 0 || ret >= 512)
+        ret = HDsnprintf(authorization, 512 + H5FD_ROS3_MAX_SECRET_TOK_LEN,
+                         "AWS4-HMAC-SHA256 Credential=%s,SignedHeaders=%s,Signature=%s", buffer2,
+                         signed_headers, buffer1);
+        if (ret <= 0 || ret >= 512 + H5FD_ROS3_MAX_SECRET_TOK_LEN)
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unable to format aws4 authorization string");
 
         /* append authorization header to http request buffer */
@@ -1440,8 +1480,9 @@ H5FD_s3comms_s3r_read(s3r_t *handle, haddr_t offset, size_t len, void *dest)
         if (p_status != CURLE_OK) {
             if (CURLE_OK != curl_easy_getinfo(curlh, CURLINFO_RESPONSE_CODE, &httpcode))
                 HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "problem getting response code")
-            fprintf(stdout, "CURL ERROR CODE: %d\nHTTP CODE: %d\n", p_status, httpcode);
+            fprintf(stdout, "CURL ERROR CODE: %d\nHTTP CODE: %ld\n", p_status, httpcode);
             fprintf(stdout, "%s\n", curl_easy_strerror(p_status));
+
             HGOTO_ERROR(H5E_VFL, H5E_CANTOPENFILE, FAIL, "problem while performing request.");
         }
         if (CURLE_OK != curl_easy_setopt(curlh, CURLOPT_ERRORBUFFER, NULL))
@@ -1474,6 +1515,18 @@ H5FD_s3comms_s3r_read(s3r_t *handle, haddr_t offset, size_t len, void *dest)
 done:
     /* clean any malloc'd resources
      */
+    if (authorization != NULL) {
+        H5MM_xfree(authorization);
+        authorization = NULL;
+    }
+    if (buffer1 != NULL) {
+        H5MM_xfree(buffer1);
+        buffer1 = NULL;
+    }
+    if (signed_headers != NULL) {
+        H5MM_xfree(signed_headers);
+        signed_headers = NULL;
+    }
     if (curlheaders != NULL) {
         curl_slist_free_all(curlheaders);
         curlheaders = NULL;
@@ -1592,8 +1645,7 @@ H5FD_s3comms_aws_canonical_request(char *canonical_request_dest, int _cr_size, c
     size_t      sh_size      = (size_t)_sh_size;
     size_t      cr_len       = 0; /* working length of canonical request str */
     size_t      sh_len       = 0; /* working length of signed headers str */
-    char        tmpstr[256 + 1];
-    tmpstr[256] = 0; /* terminating NULL */
+    char        tmpstr[1024];
 
     /* "query params" refers to the optional element in the URL, e.g.
      *     http://bucket.aws.com/myfile.txt?max-keys=2&prefix=J
@@ -1626,6 +1678,7 @@ H5FD_s3comms_aws_canonical_request(char *canonical_request_dest, int _cr_size, c
               (size_t)3); /* three newline chars */
     if (cr_len >= cr_size)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not enough space in canonical request");
+
     /* TODO: compiler warning */
     ret = HDsnprintf(canonical_request_dest, (cr_size - 1), "%s\n%s\n%s\n", http_request->verb,
                      http_request->resource, query_params);
@@ -1638,8 +1691,8 @@ H5FD_s3comms_aws_canonical_request(char *canonical_request_dest, int _cr_size, c
 
         assert(node->magic == S3COMMS_HRB_NODE_MAGIC);
 
-        ret = HDsnprintf(tmpstr, 256, "%s:%s\n", node->lowername, node->value);
-        if (ret < 0 || ret >= 256)
+        ret = HDsnprintf(tmpstr, 1024, "%s:%s\n", node->lowername, node->value);
+        if (ret < 0 || ret >= 1024)
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unable to concatenate HTTP header %s:%s",
                         node->lowername, node->value);
         cr_len += HDstrlen(tmpstr);
@@ -1647,8 +1700,8 @@ H5FD_s3comms_aws_canonical_request(char *canonical_request_dest, int _cr_size, c
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not enough space in canonical request");
         HDstrcat(canonical_request_dest, tmpstr);
 
-        ret = HDsnprintf(tmpstr, 256, "%s;", node->lowername);
-        if (ret < 0 || ret >= 256)
+        ret = HDsnprintf(tmpstr, 1024, "%s;", node->lowername);
+        if (ret < 0 || ret >= 1024)
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unable to append semicolon to lowername %s",
                         node->lowername);
         sh_len += HDstrlen(tmpstr);
diff --git a/src/H5FDs3comms.h b/src/H5FDs3comms.h
index 1b21ad7..47857f6 100644
--- a/src/H5FDs3comms.h
+++ b/src/H5FDs3comms.h
@@ -478,6 +478,7 @@ typedef struct {
     char          *region;
     char          *secret_id;
     unsigned char *signing_key;
+    char          *token;
 } s3r_t;
 
 #define S3COMMS_S3R_MAGIC 0x44d8d79
@@ -509,7 +510,7 @@ H5_DLL herr_t H5FD_s3comms_s3r_close(s3r_t *handle);
 H5_DLL size_t H5FD_s3comms_s3r_get_filesize(s3r_t *handle);
 
 H5_DLL s3r_t *H5FD_s3comms_s3r_open(const char url[], const char region[], const char id[],
-                                    const unsigned char signing_key[]);
+                                    const unsigned char signing_key[], const char token[]);
 
 H5_DLL herr_t H5FD_s3comms_s3r_read(s3r_t *handle, haddr_t offset, size_t len, void *dest);