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authorBenoît Ganne <bganne@cisco.com>2021-09-08 16:26:52 +0200
committerFlorin Coras <florin.coras@gmail.com>2021-09-09 22:22:53 +0000
commit10bb21fb13aa74dcb0c2c0841d41a698bb274fbe (patch)
treedc96db1f8982973629ddbcacb75dd8e2ba24aaa3
parent2ac5c11cd32795ec917ff038262aee113d9e792a (diff)
vlib: fix vlib_buffer_enqueue_to_next() overflow
vlib_buffer_enqueue_to_next() requires to allow overflow of up to 63 elements of 'buffer' and 'nexts' array. - add helper to compute the minimum size - fix occurences in session and async crypto Type: fix Change-Id: If8d7eebc5bf9beba71ba194aec0f79b8eb6d5843 Signed-off-by: Benoît Ganne <bganne@cisco.com>
-rw-r--r--src/vlib/buffer_node.h25
-rw-r--r--src/vnet/crypto/node.c8
-rw-r--r--src/vnet/session/session_node.c6
3 files changed, 32 insertions, 7 deletions
diff --git a/src/vlib/buffer_node.h b/src/vlib/buffer_node.h
index 9ca43d425fc..10ebd253c1b 100644
--- a/src/vlib/buffer_node.h
+++ b/src/vlib/buffer_node.h
@@ -335,6 +335,17 @@ generic_buffer_node_inline (vlib_main_t * vm,
return frame->n_vectors;
}
+/* Minimum size for the 'buffers' and 'nexts' arrays to be used when calling
+ * vlib_buffer_enqueue_to_next().
+ * Because of optimizations, vlib_buffer_enqueue_to_next() will access
+ * past 'count' elements in the 'buffers' and 'nexts' arrays, IOW it
+ * will overflow.
+ * Those overflow elements are ignored in the final result so they do not
+ * need to be properly initialized, however if the array is allocated right
+ * before the end of a page and the next page is not mapped, accessing the
+ * overflow elements will trigger a segfault. */
+#define VLIB_BUFFER_ENQUEUE_MIN_SIZE(n) round_pow2 ((n), 64)
+
static_always_inline void
vlib_buffer_enqueue_to_next (vlib_main_t * vm, vlib_node_runtime_t * node,
u32 * buffers, u16 * nexts, uword count)
@@ -345,6 +356,20 @@ vlib_buffer_enqueue_to_next (vlib_main_t * vm, vlib_node_runtime_t * node,
}
static_always_inline void
+vlib_buffer_enqueue_to_next_vec (vlib_main_t *vm, vlib_node_runtime_t *node,
+ u32 **buffers, u16 **nexts, uword count)
+{
+ const u32 bl = vec_len (*buffers), nl = vec_len (*nexts);
+ const u32 c = VLIB_BUFFER_ENQUEUE_MIN_SIZE (count);
+ ASSERT (bl >= count && nl >= count);
+ vec_validate (*buffers, c);
+ vec_validate (*nexts, c);
+ vlib_buffer_enqueue_to_next (vm, node, *buffers, *nexts, count);
+ vec_set_len (*buffers, bl);
+ vec_set_len (*nexts, nl);
+}
+
+static_always_inline void
vlib_buffer_enqueue_to_single_next (vlib_main_t * vm,
vlib_node_runtime_t * node, u32 * buffers,
u16 next_index, u32 count)
diff --git a/src/vnet/crypto/node.c b/src/vnet/crypto/node.c
index 7f34ec10fff..e753f1ad1db 100644
--- a/src/vnet/crypto/node.c
+++ b/src/vnet/crypto/node.c
@@ -114,8 +114,8 @@ crypto_dequeue_frame (vlib_main_t * vm, vlib_node_runtime_t * node,
n_cache += cf->n_elts;
if (n_cache >= VLIB_FRAME_SIZE)
{
- vlib_buffer_enqueue_to_next (vm, node, ct->buffer_indices,
- ct->nexts, n_cache);
+ vlib_buffer_enqueue_to_next_vec (vm, node, &ct->buffer_indices,
+ &ct->nexts, n_cache);
n_cache = 0;
}
@@ -168,8 +168,8 @@ VLIB_NODE_FN (crypto_dispatch_node) (vlib_main_t * vm,
}
/* *INDENT-ON* */
if (n_cache)
- vlib_buffer_enqueue_to_next (vm, node, ct->buffer_indices, ct->nexts,
- n_cache);
+ vlib_buffer_enqueue_to_next_vec (vm, node, &ct->buffer_indices, &ct->nexts,
+ n_cache);
return n_dispatched;
}
diff --git a/src/vnet/session/session_node.c b/src/vnet/session/session_node.c
index 72df07b1d6d..981fa66eae1 100644
--- a/src/vnet/session/session_node.c
+++ b/src/vnet/session/session_node.c
@@ -1660,9 +1660,9 @@ static void
session_flush_pending_tx_buffers (session_worker_t * wrk,
vlib_node_runtime_t * node)
{
- vlib_buffer_enqueue_to_next (wrk->vm, node, wrk->pending_tx_buffers,
- wrk->pending_tx_nexts,
- vec_len (wrk->pending_tx_nexts));
+ vlib_buffer_enqueue_to_next_vec (wrk->vm, node, &wrk->pending_tx_buffers,
+ &wrk->pending_tx_nexts,
+ vec_len (wrk->pending_tx_nexts));
vec_reset_length (wrk->pending_tx_buffers);
vec_reset_length (wrk->pending_tx_nexts);
}