36 lines
1.3 KiB
Diff
36 lines
1.3 KiB
Diff
From 57c6e6b00247ad289a27648213d7ad2306fe3931 Mon Sep 17 00:00:00 2001
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From: Frediano Ziglio <freddy77@gmail.com>
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Date: Thu, 30 Apr 2020 10:19:09 +0100
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Subject: [PATCH spice-common 4/4] quic: Avoid possible buffer overflow in
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find_bucket
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Proved by fuzzing the code.
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Signed-off-by: Frediano Ziglio <freddy77@gmail.com>
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Acked-by: Uri Lublin <uril@redhat.com>
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---
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common/quic_family_tmpl.c | 7 ++++++-
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1 file changed, 6 insertions(+), 1 deletion(-)
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diff --git a/subprojects/spice-common/common/quic_family_tmpl.c b/subprojects/spice-common/common/quic_family_tmpl.c
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index 8a5f7d2..6cc051b 100644
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--- a/subprojects/spice-common/common/quic_family_tmpl.c
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+++ b/subprojects/spice-common/common/quic_family_tmpl.c
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@@ -103,7 +103,12 @@ static s_bucket *FNAME(find_bucket)(Channel *channel, const unsigned int val)
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{
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spice_extra_assert(val < (0x1U << BPC));
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- return channel->_buckets_ptrs[val];
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+ /* The and (&) here is to avoid buffer overflows in case of garbage or malicious
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+ * attempts. Is much faster then using comparisons and save us from such situations.
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+ * Note that on normal build the check above won't be compiled as this code path
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+ * is pretty hot and would cause speed regressions.
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+ */
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+ return channel->_buckets_ptrs[val & ((1U << BPC) - 1)];
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}
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#undef FNAME
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--
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2.25.4
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