47 lines
1.5 KiB
Diff
47 lines
1.5 KiB
Diff
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From 1e1166661ef5c6776189aeed09b39f1a91e107e3 Mon Sep 17 00:00:00 2001
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From: Ludovic Rousseau <ludovic.rousseau@free.fr>
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Date: Sat, 8 Aug 2020 15:39:17 +0200
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Subject: [PATCH 1/6] T0ProcACK: fix a potential problem
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" Apparently, the fuzzer found one more similar bug: T0ProcACK() can be
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called with the |proc_len| parameter equal to -1, leading to
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stack-buffer-overflow.
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The stack trace is:
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#1 0x56eee7 in T0ProcACK /ssd/ccid/src/fuzzer/../commands.c:1988:3
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#2 0x56d1d1 in CmdXfrBlockCHAR_T0 /ssd/ccid/src/fuzzer/../commands.c:2253:20
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#3 0x5754cc in IFDHTransmitToICC /ssd/ccid/src/fuzzer/../ifdhandler.c:1403:17
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and the T0ProcACK() call is made from this line:
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https://salsa.debian.org/rousseau/CCID/-/blob/c122e4f38cc7d1ffdb1fc0cece49145930d4634a/src/commands.c#L2197
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The negative |proc_len| is the result of this equation: |exp_len -
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*rcv_len|, with exp_len=2, *rcv_len=3 in the found scenario. "
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The problem has been found by an automatic buzzer, not by a real problem
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in the field.
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Thanks to Maksim Ivanov for the bug report
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---
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src/commands.c | 3 +++
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1 file changed, 3 insertions(+)
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diff --git a/src/commands.c b/src/commands.c
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index 07bad44..c00c2d5 100644
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--- a/src/commands.c
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+++ b/src/commands.c
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@@ -1852,6 +1852,9 @@ static RESPONSECODE T0ProcACK(unsigned int reader_index,
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DEBUG_COMM2("Enter, is_rcv = %d", is_rcv);
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+ if (proc_len < 0)
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+ return IFD_COMMUNICATION_ERROR;
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+
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if (is_rcv == 1)
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{ /* Receiving mode */
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unsigned int remain_len;
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--
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1.8.3.1
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