48 lines
2.1 KiB
Diff
48 lines
2.1 KiB
Diff
From fc85be7123050b91b054e45b91c78d3241a5047a Mon Sep 17 00:00:00 2001
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From: Alan Antonuk <alan.antonuk@gmail.com>
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Date: Sun, 3 Nov 2019 23:50:07 -0800
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Subject: [PATCH] lib: check frame_size is >= INT32_MAX
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When parsing a frame header, validate that the frame_size is less than
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or equal to INT32_MAX. Given frame_max is limited between 0 and
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INT32_MAX in amqp_login and friends, this does not change the API.
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This prevents a potential buffer overflow when a malicious client sends
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a frame_size that is close to UINT32_MAX, in which causes an overflow
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when computing state->target_size resulting in a small value there. A
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buffer is then allocated with the small amount, then memcopy copies the
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frame_size writing to memory beyond the end of the buffer.
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---
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librabbitmq/amqp_connection.c | 15 ++++++++++++---
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1 file changed, 12 insertions(+), 3 deletions(-)
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diff --git librabbitmq/amqp_connection.c librabbitmq/amqp_connection.c
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index 034b2e96..b106f70a 100644
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--- librabbitmq/amqp_connection.c
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+++ librabbitmq/amqp_connection.c
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@@ -287,12 +287,21 @@ int amqp_handle_input(amqp_connection_state_t state, amqp_bytes_t received_data,
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case CONNECTION_STATE_HEADER: {
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amqp_channel_t channel;
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amqp_pool_t *channel_pool;
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- /* frame length is 3 bytes in */
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+ uint32_t frame_size;
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+
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channel = amqp_d16(amqp_offset(raw_frame, 1));
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- state->target_size =
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- amqp_d32(amqp_offset(raw_frame, 3)) + HEADER_SIZE + FOOTER_SIZE;
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+ /* frame length is 3 bytes in */
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+ frame_size = amqp_d32(amqp_offset(raw_frame, 3));
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+ /* To prevent the target_size calculation below from overflowing, check
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+ * that the stated frame_size is smaller than a signed 32-bit. Given
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+ * the library only allows configuring frame_max as an int32_t, and
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+ * frame_size is uint32_t, the math below is safe from overflow. */
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+ if (frame_size >= INT32_MAX) {
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+ return AMQP_STATUS_BAD_AMQP_DATA;
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+ }
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+ state->target_size = frame_size + HEADER_SIZE + FOOTER_SIZE;
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if ((size_t)state->frame_max < state->target_size) {
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return AMQP_STATUS_BAD_AMQP_DATA;
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}
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