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Commit f95b33d6 authored by Eric Biggers's avatar Eric Biggers Committed by Greg Kroah-Hartman
Browse files

509: fix printing uninitialized stack memory when OID is empty 




[ Upstream commit 8dfd2f22d3bf3ab7714f7495ad5d897b8845e8c1 ]

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: 4f73175d ("X.509: Add utility functions to render OIDs as strings")
Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarSasha Levin <alexander.levin@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 251efedb

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);