From: Gustavo A. R. Silva gustavoars@kernel.org
commit 8d8d1dbefc423d42d626cf5b81aac214870ebaab upstream.
While addressing some warnings generated by -Warray-bounds, I found this bug that was introduced back in 2017:
CC [M] fs/cifs/smb2pdu.o fs/cifs/smb2pdu.c: In function ‘SMB2_negotiate’: fs/cifs/smb2pdu.c:822:16: warning: array subscript 1 is above array bounds of ‘__le16[1]’ {aka ‘short unsigned int[1]’} [-Warray-bounds] 822 | req->Dialects[1] = cpu_to_le16(SMB30_PROT_ID); | ~~~~~~~~~~~~~^~~ fs/cifs/smb2pdu.c:823:16: warning: array subscript 2 is above array bounds of ‘__le16[1]’ {aka ‘short unsigned int[1]’} [-Warray-bounds] 823 | req->Dialects[2] = cpu_to_le16(SMB302_PROT_ID); | ~~~~~~~~~~~~~^~~ fs/cifs/smb2pdu.c:824:16: warning: array subscript 3 is above array bounds of ‘__le16[1]’ {aka ‘short unsigned int[1]’} [-Warray-bounds] 824 | req->Dialects[3] = cpu_to_le16(SMB311_PROT_ID); | ~~~~~~~~~~~~~^~~ fs/cifs/smb2pdu.c:816:16: warning: array subscript 1 is above array bounds of ‘__le16[1]’ {aka ‘short unsigned int[1]’} [-Warray-bounds] 816 | req->Dialects[1] = cpu_to_le16(SMB302_PROT_ID); | ~~~~~~~~~~~~~^~~
At the time, the size of array _Dialects_ was changed from 1 to 3 in struct validate_negotiate_info_req, and then in 2019 it was changed from 3 to 4, but those changes were never made in struct smb2_negotiate_req, which has led to a 3 and a half years old out-of-bounds bug in function SMB2_negotiate() (fs/cifs/smb2pdu.c).
Fix this by increasing the size of array _Dialects_ in struct smb2_negotiate_req to 4.
Fixes: 9764c02fcbad ("SMB3: Add support for multidialect negotiate (SMB2.1 and later)") Fixes: d5c7076b772a ("smb3: add smb3.1.1 to default dialect list") Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva gustavoars@kernel.org Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/cifs/smb2pdu.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/cifs/smb2pdu.h +++ b/fs/cifs/smb2pdu.h @@ -206,7 +206,7 @@ struct smb2_negotiate_req { __le32 NegotiateContextOffset; /* SMB3.1.1 only. MBZ earlier */ __le16 NegotiateContextCount; /* SMB3.1.1 only. MBZ earlier */ __le16 Reserved2; - __le16 Dialects[1]; /* One dialect (vers=) at a time for now */ + __le16 Dialects[4]; /* BB expand this if autonegotiate > 4 dialects */ } __packed;
/* Dialects */