Commit a5bdc726 authored Sep 03, 2018 by Stephen Rothwell Committed by Greg Kroah-Hartman Oct 10, 2018

fs/cifs: suppress a string overflow warning



[ Upstream commit bcfb84a996f6fa90b5e6e2954b2accb7a4711097 ]

A powerpc build of cifs with gcc v8.2.0 produces this warning:

fs/cifs/cifssmb.c: In function ‘CIFSSMBNegotiate’:
fs/cifs/cifssmb.c:605:3: warning: ‘strncpy’ writing 16 bytes into a region of size 1 overflows the destination [-Wstringop-overflow=]
   strncpy(pSMB->DialectsArray+count, protocols[i].name, 16);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Since we are already doing a strlen() on the source, change the strncpy
to a memcpy().

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 3941dbe1

fs/cifs/cifssmb.c

+8 −3

Original line number	Diff line number	Diff line
		@@ -589,10 +589,15 @@ CIFSSMBNegotiate(const unsigned int xid, struct cifs_ses *ses)
		}

		count = 0;
		/*
		* We know that all the name entries in the protocols array
		* are short (< 16 bytes anyway) and are NUL terminated.
		*/
		for (i = 0; i < CIFS_NUM_PROT; i++) {
		strncpy(pSMB->DialectsArray+count, protocols[i].name, 16);
		count += strlen(protocols[i].name) + 1;
		/* null at end of source and target buffers anyway */
		size_t len = strlen(protocols[i].name) + 1;

		memcpy(pSMB->DialectsArray+count, protocols[i].name, len);
		count += len;
		}
		inc_rfc1001_len(pSMB, count);
		pSMB->ByteCount = cpu_to_le16(count);