39 lines
1.5 KiB
Diff
39 lines
1.5 KiB
Diff
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From e37b620fe8f14535d737e89a4dcabaed4517bf1a Mon Sep 17 00:00:00 2001
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From: Tim Kientzle <kientzle@acm.org>
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Date: Sun, 21 Aug 2016 10:51:43 -0700
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Subject: [PATCH] Issue #767: Buffer overflow printing a filename
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The safe_fprintf function attempts to ensure clean output for an
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arbitrary sequence of bytes by doing a trial conversion of the
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multibyte characters to wide characters -- if the resulting wide
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character is printable then we pass through the corresponding bytes
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unaltered, otherwise, we convert them to C-style ASCII escapes.
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The stack trace in Issue #767 suggest that the 20-byte buffer
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was getting overflowed trying to format a non-printable multibyte
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character. This should only happen if there is a valid multibyte
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character of more than 5 bytes that was unprintable. (Each byte
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would get expanded to a four-charcter octal-style escape of the form
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"\123" resulting in >20 characters for the >5 byte multibyte character.)
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I've not been able to reproduce this, but have expanded the conversion
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buffer to 128 bytes on the belief that no multibyte character set
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has a single character of more than 32 bytes.
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---
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tar/util.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/tar/util.c b/tar/util.c
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index 9ff22f2..2b4aebe 100644
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--- a/tar/util.c
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+++ b/tar/util.c
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@@ -182,7 +182,7 @@ safe_fprintf(FILE *f, const char *fmt, ...)
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}
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/* If our output buffer is full, dump it and keep going. */
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- if (i > (sizeof(outbuff) - 20)) {
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+ if (i > (sizeof(outbuff) - 128)) {
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outbuff[i] = '\0';
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fprintf(f, "%s", outbuff);
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i = 0;
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