2023-09-07 21:23:50 -04:00
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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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2023-09-05 20:50:31 -04:00
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From: Brian Delwiche <delwiche@google.com>
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Date: Tue, 11 Apr 2023 23:05:45 +0000
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Subject: [PATCH] Fix UAF in gatt_cl.cc
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gatt_cl.cc accesses a header field after the buffer holding it may have
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been freed.
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Track the relevant state as a local variable instead.
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Bug: 274617156
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Test: atest: bluetooth, validated against fuzzer
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Tag: #security
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Ignore-AOSP-First: Security
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(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:cbaa83627b328eee8f2e26188909a5ebfb0388d5)
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Merged-In: I085ecfa1a9ba098ecbfecbd3cb3e263ae13f9724
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Change-Id: I085ecfa1a9ba098ecbfecbd3cb3e263ae13f9724
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---
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stack/gatt/gatt_cl.c | 7 ++++++-
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1 file changed, 6 insertions(+), 1 deletion(-)
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diff --git a/stack/gatt/gatt_cl.c b/stack/gatt/gatt_cl.c
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2023-09-07 21:23:50 -04:00
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index 3797d9684..bec320846 100644
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2023-09-05 20:50:31 -04:00
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--- a/stack/gatt/gatt_cl.c
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+++ b/stack/gatt/gatt_cl.c
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2023-09-07 21:23:50 -04:00
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@@ -653,13 +653,18 @@ void gatt_process_prep_write_rsp (tGATT_TCB *p_tcb, tGATT_CLCB *p_clcb, UINT8 op
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2023-09-05 20:50:31 -04:00
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memcpy (value.value, p, value.len);
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+ BOOLEAN subtype_is_write_prepare = (p_clcb->op_subtype == GATT_WRITE_PREPARE);
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+
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if (!gatt_check_write_long_terminate(p_tcb, p_clcb, &value))
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{
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gatt_send_prepare_write(p_tcb, p_clcb);
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return;
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}
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- if (p_clcb->op_subtype == GATT_WRITE_PREPARE)
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+ // We now know that we have not terminated, or else we would have returned
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+ // early. We free the buffer only if the subtype is not equal to
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+ // GATT_WRITE_PREPARE, so checking here is adequate to prevent UAF.
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+ if (subtype_is_write_prepare)
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{
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/* application should verify handle offset
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and value are matched or not */
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