philipp / rpms / dhcp

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Blame SOURCES/dhcp-4.3.6-options_overflow.patch

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diff --git a/common/options.c b/common/options.c
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index 83e0384..8a1deca 100644
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--- a/common/options.c
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+++ b/common/options.c
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@@ -1672,7 +1672,8 @@ format_min_length(format, oc)
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 /* Format the specified option so that a human can easily read it. */
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-
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+/* Maximum pretty printed size */
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+#define MAX_OUTPUT_SIZE 32*1024
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 const char *pretty_print_option (option, data, len, emit_commas, emit_quotes)
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 	struct option *option;
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 	const unsigned char *data;
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@@ -1680,8 +1681,9 @@ const char *pretty_print_option (option, data, len, emit_commas, emit_quotes)
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 	int emit_commas;
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 	int emit_quotes;
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 {
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-	static char optbuf [32768]; /* XXX */
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-	static char *endbuf = &optbuf[sizeof(optbuf)];
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+	/* We add 128 byte pad so we don't have to add checks everywhere. */
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+	static char optbuf [MAX_OUTPUT_SIZE + 128]; /* XXX */
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+	static char *endbuf = optbuf + MAX_OUTPUT_SIZE;
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 	int hunksize = 0;
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 	int opthunk = 0;
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 	int hunkinc = 0;
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@@ -2132,7 +2134,14 @@ const char *pretty_print_option (option, data, len, emit_commas, emit_quotes)
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 				log_error ("Unexpected format code %c",
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 					   fmtbuf [j]);
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 			}
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+
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 			op += strlen (op);
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+			if (op >= endbuf) {
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+				log_error ("Option data exceeds"
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+					   " maximum size %d", MAX_OUTPUT_SIZE);
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+					   return ("<error>");
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+			}
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+
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 			if (dp == data + len)
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 				break;
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 			if (j + 1 < numelem && comma != ':')