4.4-stable review patch. If anyone has any objections, please let me know.
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From: Stephen Rothwell sfr@canb.auug.org.au
[ 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 --- fs/cifs/cifssmb.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
--- a/fs/cifs/cifssmb.c +++ b/fs/cifs/cifssmb.c @@ -577,10 +577,15 @@ CIFSSMBNegotiate(const unsigned int xid, }
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);