509: fix printing uninitialized stack memory when OID is empty (8dfd2f22) · Commits · 戴 / test

Callers of sprint_oid() do not check its return value before printing the result. In the case where the OID is zero-length, -EBADMSG was being returned without anything being written to the buffer, resulting in uninitialized stack memory being printed. Fix this by writing "(bad)" to the buffer in the cases where -EBADMSG is returned. Fixes: ("X.509: Add utility functions to render OIDs as strings") Signed-off-by:

Eric Biggers <ebiggers@google.com> Signed-off-by:

David Howells <dhowells@redhat.com>

lib/oid_registry.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -116,7 +116,7 @@ int sprint_oid(const void data, size_t datasize, char buffer, size_t bufsize)
		int count;

		if (v >= end)
		return -EBADMSG;
		goto bad;

		n = *v++;
		ret = count = snprintf(buffer, bufsize, "%u.%u", n / 40, n % 40);
		@@ -134,7 +134,7 @@ int sprint_oid(const void data, size_t datasize, char buffer, size_t bufsize)
		num = n & 0x7f;
		do {
		if (v >= end)
		return -EBADMSG;
		goto bad;
		n = *v++;
		num <<= 7;
		num \|= n & 0x7f;
		@@ -148,6 +148,10 @@ int sprint_oid(const void data, size_t datasize, char buffer, size_t bufsize)
		}

		return ret;

		bad:
		snprintf(buffer, bufsize, "(bad)");
		return -EBADMSG;
		}
		EXPORT_SYMBOL_GPL(sprint_oid);

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