X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=ssl%2Fpacket.c;h=3479f1fed8b2a0d4421aef199455d425411fa16b;hp=d4f964922d2a1e0acd74e54ce774e1914b6d81b7;hb=4afc60605abcf1ac8373838c71e94a131d29253e;hpb=0217dd19c00657b8bfd2bce1090785eb32abb235

diff --git a/ssl/packet.c b/ssl/packet.c
index d4f964922d..3479f1fed8 100644
--- a/ssl/packet.c
+++ b/ssl/packet.c
@@ -7,56 +7,92 @@
  * https://www.openssl.org/source/license.html
  */
 
+#include <assert.h>
 #include "packet_locl.h"
 
-/*
- * Allocate bytes in the WPACKET for the output. This reserves the bytes
- * and count them as "written", but doesn't actually do the writing.
- */
+#define DEFAULT_BUF_SIZE    256
+
 int WPACKET_allocate_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)
 {
-    if (pkt->subs == NULL || len == 0)
+    if (!WPACKET_reserve_bytes(pkt, len, allocbytes))
+        return 0;
+
+    pkt->written += len;
+    pkt->curr += len;
+    return 1;
+}
+
+int WPACKET_sub_allocate_bytes__(WPACKET *pkt, size_t len,
+                                 unsigned char **allocbytes, size_t lenbytes)
+{
+    if (!WPACKET_start_sub_packet_len__(pkt, lenbytes)
+            || !WPACKET_allocate_bytes(pkt, len, allocbytes)
+            || !WPACKET_close(pkt))
         return 0;
 
-    if (SIZE_MAX - pkt->written < len)
+    return 1;
+}
+
+#define GETBUF(p)   (((p)->staticbuf != NULL) \
+                     ? (p)->staticbuf : (unsigned char *)(p)->buf->data)
+
+int WPACKET_reserve_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)
+{
+    /* Internal API, so should not fail */
+    assert(pkt->subs != NULL && len != 0);
+    if (pkt->subs == NULL || len == 0)
         return 0;
 
-    if (pkt->maxsize > 0 && pkt->written + len > pkt->maxsize)
+    if (pkt->maxsize - pkt->written < len)
         return 0;
 
-    if (pkt->buf->length - pkt->written < len) {
+    if (pkt->staticbuf == NULL && (pkt->buf->length - pkt->written < len)) {
         size_t newlen;
+        size_t reflen;
 
-        if (pkt->buf->length > SIZE_MAX / 2)
+        reflen = (len > pkt->buf->length) ? len : pkt->buf->length;
+
+        if (reflen > SIZE_MAX / 2) {
             newlen = SIZE_MAX;
-        else
-            newlen = pkt->buf->length * 2;
+        } else {
+            newlen = reflen * 2;
+            if (newlen < DEFAULT_BUF_SIZE)
+                newlen = DEFAULT_BUF_SIZE;
+        }
         if (BUF_MEM_grow(pkt->buf, newlen) == 0)
             return 0;
     }
-    pkt->written += len;
-    *allocbytes = pkt->curr;
-    pkt->curr += len;
+    if (allocbytes != NULL)
+        *allocbytes = WPACKET_get_curr(pkt);
 
     return 1;
 }
 
-/*
- * Initialise a WPACKET with the buffer in |buf|. The buffer must exist
- * for the whole time that the WPACKET is being used. Additionally |lenbytes| of
- * data is preallocated at the start of the buffer to store the length of the
- * WPACKET once we know it.
- */
-int WPACKET_init_len(WPACKET *pkt, BUF_MEM *buf, size_t lenbytes)
+int WPACKET_sub_reserve_bytes__(WPACKET *pkt, size_t len,
+                                unsigned char **allocbytes, size_t lenbytes)
 {
-    /* Sanity check */
-    if (buf == NULL)
+    if (!WPACKET_reserve_bytes(pkt, lenbytes + len, allocbytes))
         return 0;
 
-    pkt->buf = buf;
-    pkt->curr = (unsigned char *)buf->data;
+    *allocbytes += lenbytes;
+
+    return 1;
+}
+
+static size_t maxmaxsize(size_t lenbytes)
+{
+    if (lenbytes >= sizeof(size_t) || lenbytes == 0)
+        return SIZE_MAX;
+
+    return ((size_t)1 << (lenbytes * 8)) - 1 + lenbytes;
+}
+
+static int wpacket_intern_init_len(WPACKET *pkt, size_t lenbytes)
+{
+    unsigned char *lenchars;
+
+    pkt->curr = 0;
     pkt->written = 0;
-    pkt->maxsize = 0;
 
     pkt->subs = OPENSSL_zalloc(sizeof(*pkt->subs));
     if (pkt->subs == NULL)
@@ -68,47 +104,56 @@ int WPACKET_init_len(WPACKET *pkt, BUF_MEM *buf, size_t lenbytes)
     pkt->subs->pwritten = lenbytes;
     pkt->subs->lenbytes = lenbytes;
 
-    if (!WPACKET_allocate_bytes(pkt, lenbytes, &(pkt->subs->packet_len))) {
+    if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars)) {
         OPENSSL_free(pkt->subs);
         pkt->subs = NULL;
         return 0;
     }
+    pkt->subs->packet_len = lenchars - GETBUF(pkt);
 
     return 1;
 }
 
-/*
- * Same as WPACKET_init_len except there is no preallocation of the WPACKET
- * length.
- */
-int WPACKET_init(WPACKET *pkt, BUF_MEM *buf)
+int WPACKET_init_static_len(WPACKET *pkt, unsigned char *buf, size_t len,
+                            size_t lenbytes)
 {
-    return WPACKET_init_len(pkt, buf, 0);
+    size_t max = maxmaxsize(lenbytes);
+
+    /* Internal API, so should not fail */
+    assert(buf != NULL && len > 0);
+    if (buf == NULL || len == 0)
+        return 0;
+
+    pkt->staticbuf = buf;
+    pkt->buf = NULL;
+    pkt->maxsize = (max < len) ? max : len;
+
+    return wpacket_intern_init_len(pkt, lenbytes);
 }
 
-/*
- * Set the WPACKET length, and the location for where we should write that
- * length. Normally this will be at the start of the WPACKET, and therefore
- * the WPACKET would have been initialised via WPACKET_init_len(). However there
- * is the possibility that the length needs to be written to some other location
- * other than the start of the WPACKET. In that case init via WPACKET_init() and
- * then set the location for the length using this function.
- */
-int WPACKET_set_packet_len(WPACKET *pkt, unsigned char *packet_len,
-                           size_t lenbytes)
+int WPACKET_init_len(WPACKET *pkt, BUF_MEM *buf, size_t lenbytes)
 {
-    /* We only allow this to be set once */
-    if (pkt->subs == NULL)
+    /* Internal API, so should not fail */
+    assert(buf != NULL);
+    if (buf == NULL)
         return 0;
 
-    pkt->subs->lenbytes = lenbytes;
-    pkt->subs->packet_len = packet_len;
+    pkt->staticbuf = NULL;
+    pkt->buf = buf;
+    pkt->maxsize = maxmaxsize(lenbytes);
 
-    return 1;
+    return wpacket_intern_init_len(pkt, lenbytes);
+}
+
+int WPACKET_init(WPACKET *pkt, BUF_MEM *buf)
+{
+    return WPACKET_init_len(pkt, buf, 0);
 }
 
 int WPACKET_set_flags(WPACKET *pkt, unsigned int flags)
 {
+    /* Internal API, so should not fail */
+    assert(pkt->subs != NULL);
     if (pkt->subs == NULL)
         return 0;
 
@@ -117,23 +162,43 @@ int WPACKET_set_flags(WPACKET *pkt, unsigned int flags)
     return 1;
 }
 
+/* Store the |value| of length |len| at location |data| */
+static int put_value(unsigned char *data, size_t value, size_t len)
+{
+    for (data += len - 1; len > 0; len--) {
+        *data = (unsigned char)(value & 0xff);
+        data--;
+        value >>= 8;
+    }
+
+    /* Check whether we could fit the value in the assigned number of bytes */
+    if (value > 0)
+        return 0;
+
+    return 1;
+}
+
 
 /*
- * Internal helper function used by WPACKET_close() and WPACKET_finish() to
- * close a sub-packet and write out its length if necessary.
+ * Internal helper function used by WPACKET_close(), WPACKET_finish() and
+ * WPACKET_fill_lengths() to close a sub-packet and write out its length if
+ * necessary. If |doclose| is 0 then it goes through the motions of closing
+ * (i.e. it fills in all the lengths), but doesn't actually close anything.
  */
-static int wpacket_intern_close(WPACKET *pkt)
+static int wpacket_intern_close(WPACKET *pkt, WPACKET_SUB *sub, int doclose)
 {
-    size_t packlen;
-    WPACKET_SUB *sub = pkt->subs;
+    size_t packlen = pkt->written - sub->pwritten;
 
-    packlen = pkt->written - sub->pwritten;
     if (packlen == 0
-            && sub->flags & OPENSSL_WPACKET_FLAGS_NON_ZERO_LENGTH)
+            && (sub->flags & WPACKET_FLAGS_NON_ZERO_LENGTH) != 0)
         return 0;
 
     if (packlen == 0
-            && sub->flags & OPENSSL_WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH) {
+            && sub->flags & WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH) {
+        /* We can't handle this case. Return an error */
+        if (!doclose)
+            return 0;
+
         /* Deallocate any bytes allocated for the length of the WPACKET */
         if ((pkt->curr - sub->lenbytes) == sub->packet_len) {
             pkt->written -= sub->lenbytes;
@@ -141,75 +206,79 @@ static int wpacket_intern_close(WPACKET *pkt)
         }
 
         /* Don't write out the packet length */
-        sub->packet_len = NULL;
+        sub->packet_len = 0;
+        sub->lenbytes = 0;
     }
 
     /* Write out the WPACKET length if needed */
-    if (sub->packet_len != NULL) {
-        size_t lenbytes;
+    if (sub->lenbytes > 0
+                && !put_value(&GETBUF(pkt)[sub->packet_len], packlen,
+                              sub->lenbytes))
+            return 0;
 
-        lenbytes = sub->lenbytes;
+    if (doclose) {
+        pkt->subs = sub->parent;
+        OPENSSL_free(sub);
+    }
 
-        for (; lenbytes > 0; lenbytes--) {
-            sub->packet_len[lenbytes - 1]
-                = (unsigned char)(packlen & 0xff);
-            packlen >>= 8;
-        }
-        if (packlen > 0) {
-            /*
-             * We've extended beyond the max allowed for the number of len bytes
-             */
+    return 1;
+}
+
+int WPACKET_fill_lengths(WPACKET *pkt)
+{
+    WPACKET_SUB *sub;
+
+    assert(pkt->subs != NULL);
+    if (pkt->subs == NULL)
+        return 0;
+
+    for (sub = pkt->subs; sub != NULL; sub = sub->parent) {
+        if (!wpacket_intern_close(pkt, sub, 0))
             return 0;
-        }
     }
 
-    pkt->subs = sub->parent;
-    OPENSSL_free(sub);
-
     return 1;
 }
 
-/*
- * Closes the most recent sub-packet. It also writes out the length of the
- * packet to the required location (normally the start of the WPACKET) if
- * appropriate. The top level WPACKET should be closed using WPACKET_finish()
- * instead of this function.
- */
 int WPACKET_close(WPACKET *pkt)
 {
+    /*
+     * Internal API, so should not fail - but we do negative testing of this
+     * so no assert (otherwise the tests fail)
+     */
     if (pkt->subs == NULL || pkt->subs->parent == NULL)
         return 0;
 
-    return wpacket_intern_close(pkt);
+    return wpacket_intern_close(pkt, pkt->subs, 1);
 }
 
-/*
- * The same as WPACKET_close() but only for the top most WPACKET. Additionally
- * frees memory resources for this WPACKET.
- */
 int WPACKET_finish(WPACKET *pkt)
 {
     int ret;
 
+    /*
+     * Internal API, so should not fail - but we do negative testing of this
+     * so no assert (otherwise the tests fail)
+     */
     if (pkt->subs == NULL || pkt->subs->parent != NULL)
         return 0;
 
-    ret = wpacket_intern_close(pkt);
+    ret = wpacket_intern_close(pkt, pkt->subs, 1);
+    if (ret) {
+        OPENSSL_free(pkt->subs);
+        pkt->subs = NULL;
+    }
 
-    /* We free up memory no matter whether |ret| is zero or not */
-    OPENSSL_free(pkt->subs);
-    pkt->subs = NULL;
     return ret;
 }
 
-/*
- * Initialise a new sub-packet. Additionally |lenbytes| of data is preallocated
- * at the start of the sub-packet to store its length once we know it.
- */
-int WPACKET_start_sub_packet_len(WPACKET *pkt, size_t lenbytes)
+int WPACKET_start_sub_packet_len__(WPACKET *pkt, size_t lenbytes)
 {
     WPACKET_SUB *sub;
+    unsigned char *lenchars;
 
+    /* Internal API, so should not fail */
+    assert(pkt->subs != NULL);
     if (pkt->subs == NULL)
         return 0;
 
@@ -223,68 +292,64 @@ int WPACKET_start_sub_packet_len(WPACKET *pkt, size_t lenbytes)
     sub->lenbytes = lenbytes;
 
     if (lenbytes == 0) {
-        sub->packet_len = NULL;
+        sub->packet_len = 0;
         return 1;
     }
 
-    if (!WPACKET_allocate_bytes(pkt, lenbytes, &sub->packet_len)) {
+    if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars))
         return 0;
-    }
+    /* Convert to an offset in case the underlying BUF_MEM gets realloc'd */
+    sub->packet_len = lenchars - GETBUF(pkt);
 
     return 1;
 }
 
-/*
- * Same as WPACKET_get_sub_packet_len() except no bytes are pre-allocated for
- * the sub-packet length.
- */
 int WPACKET_start_sub_packet(WPACKET *pkt)
 {
-    return WPACKET_start_sub_packet_len(pkt, 0);
+    return WPACKET_start_sub_packet_len__(pkt, 0);
 }
 
-/*
- * Write the value stored in |val| into the WPACKET. The value will consome
- * |bytes| amount of storage. An error will occur if |val| cannot be accommdated
- * in |bytes| storage, e.g. attempting to write the value 256 into 1 byte will
- * fail.
- */
-int WPACKET_put_bytes(WPACKET *pkt, unsigned int val, size_t bytes)
+int WPACKET_put_bytes__(WPACKET *pkt, unsigned int val, size_t size)
 {
     unsigned char *data;
 
-    if (bytes > sizeof(unsigned int)
-            || !WPACKET_allocate_bytes(pkt, bytes, &data))
-        return 0;
-
-    data += bytes - 1;
-    for (; bytes > 0; bytes--) {
-        *data = (unsigned char)(val & 0xff);
-        data--;
-        val >>= 8;
-    }
+    /* Internal API, so should not fail */
+    assert(size <= sizeof(unsigned int));
 
-    /* Check whether we could fit the value in the assigned number of bytes */
-    if (val > 0)
+    if (size > sizeof(unsigned int)
+            || !WPACKET_allocate_bytes(pkt, size, &data)
+            || !put_value(data, val, size))
         return 0;
 
     return 1;
 }
 
-/*
- * Set a maximum size that we will not allow the WPACKET to grow beyond. If not
- * set then there is no maximum.
- */
 int WPACKET_set_max_size(WPACKET *pkt, size_t maxsize)
 {
+    WPACKET_SUB *sub;
+    size_t lenbytes;
+
+    /* Internal API, so should not fail */
+    assert(pkt->subs != NULL);
+    if (pkt->subs == NULL)
+        return 0;
+
+    /* Find the WPACKET_SUB for the top level */
+    for (sub = pkt->subs; sub->parent != NULL; sub = sub->parent)
+        continue;
+
+    lenbytes = sub->lenbytes;
+    if (lenbytes == 0)
+        lenbytes = sizeof(pkt->maxsize);
+
+    if (maxmaxsize(lenbytes) < maxsize || maxsize < pkt->written)
+        return 0;
+
     pkt->maxsize = maxsize;
 
     return 1;
 }
 
-/*
- * Copy |len| bytes of data from |*src| into the WPACKET.
- */
 int WPACKET_memcpy(WPACKET *pkt, const void *src, size_t len)
 {
     unsigned char *dest;
@@ -300,13 +365,22 @@ int WPACKET_memcpy(WPACKET *pkt, const void *src, size_t len)
     return 1;
 }
 
-/*
- * Return the total number of bytes written so far to the underlying buffer.
- * This might includes bytes written by a parent WPACKET.
- */
+int WPACKET_sub_memcpy__(WPACKET *pkt, const void *src, size_t len,
+                         size_t lenbytes)
+{
+    if (!WPACKET_start_sub_packet_len__(pkt, lenbytes)
+            || !WPACKET_memcpy(pkt, src, len)
+            || !WPACKET_close(pkt))
+        return 0;
+
+    return 1;
+}
+
 int WPACKET_get_total_written(WPACKET *pkt, size_t *written)
 {
-    if (pkt->subs == NULL || written == NULL)
+    /* Internal API, so should not fail */
+    assert(written != NULL);
+    if (written == NULL)
         return 0;
 
     *written = pkt->written;
@@ -314,12 +388,10 @@ int WPACKET_get_total_written(WPACKET *pkt, size_t *written)
     return 1;
 }
 
-/*
- * Returns the length of the last sub-packet. This excludes any bytes allocated
- * for the length itself.
- */
 int WPACKET_get_length(WPACKET *pkt, size_t *len)
 {
+    /* Internal API, so should not fail */
+    assert(pkt->subs != NULL && len != NULL);
     if (pkt->subs == NULL || len == NULL)
         return 0;
 
@@ -327,3 +399,19 @@ int WPACKET_get_length(WPACKET *pkt, size_t *len)
 
     return 1;
 }
+
+unsigned char *WPACKET_get_curr(WPACKET *pkt)
+{
+    return GETBUF(pkt) + pkt->curr;
+}
+
+void WPACKET_cleanup(WPACKET *pkt)
+{
+    WPACKET_SUB *sub, *parent;
+
+    for (sub = pkt->subs; sub != NULL; sub = parent) {
+        parent = sub->parent;
+        OPENSSL_free(sub);
+    }
+    pkt->subs = NULL;
+}