BUG/MEDIUM: htx: Adjust length to add DATA block in an empty HTX buffer

htx_add_data() is able to partially consume data. However there is a bug
when the HTX buffer is empty.  The data length is not properly
adjusted. Thus, if it exceeds the HTX buffer size, no block is added. To fix
the issue, the length is now adjusted first.

This patch must be backported as far as 2.0.

(cherry picked from commit 28e7ba86885d60a29036bc6fa3a89777148a3762)
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/src/htx.c b/src/htx.c
index 940989c..3cc1a34 100644 (file)
--- a/src/htx.c
+++ b/src/htx.c
@@ -939,9 +939,6 @@ size_t htx_add_data(struct htx *htx, const struct ist data)
        uint32_t sz, room;
        int32_t len = data.len;
 
-       if (htx->head == -1)
-               goto add_new_block;
-
        /* Not enough space to store data */
        if (len > htx_free_data_space(htx))
                len = htx_free_data_space(htx);
@@ -949,6 +946,9 @@ size_t htx_add_data(struct htx *htx, const struct ist data)
        if (!len)
                return 0;
 
+       if (htx->head == -1)
+               goto add_new_block;
+
        /* get the tail and head block */
        tailblk = htx_get_tail_blk(htx);
        if (tailblk == NULL)