38 lines
1.3 KiB
Diff
38 lines
1.3 KiB
Diff
From d75eaee07138aa661b5c8b49242d20ba95894efb Mon Sep 17 00:00:00 2001
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From: Kevin McCarthy <kevin@8t8.us>
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Date: Sun, 3 Sep 2023 14:11:48 +0800
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Subject: [PATCH] (CVE-2023-4874) Fix write_one_header() illegal header check.
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This is another crash caused by the rfc2047 decoding bug fixed in the
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second prior commit.
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In this case, an empty header line followed by a header line starting
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with ":", would result in t==end.
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The mutt_substrdup() further below would go very badly at that point,
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with t >= end+1. This could result in either a memcpy onto NULL or a
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huge malloc call.
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Thanks to Chenyuan Mi (@morningbread) for giving a working example
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draft message of the rfc2047 decoding flaw. This allowed me, with
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further testing, to discover this additional crash bug.
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(cherry picked from commit a4752eb0ae0a521eec02e59e51ae5daedf74fda0)
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---
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sendlib.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/sendlib.c b/sendlib.c
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index b0b94b4f..7d2feb62 100644
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--- a/sendlib.c
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+++ b/sendlib.c
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@@ -2121,7 +2121,7 @@ static int write_one_header (FILE *fp, int pfxw, int max, int wraplen,
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else
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{
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t = strchr (start, ':');
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- if (!t || t > end)
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+ if (!t || t >= end)
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{
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dprint (1, (debugfile, "mwoh: warning: header not in "
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"'key: value' format!\n"));
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