From c2ce58335151d81235a52b09cae3d6a8cd2fe778 Mon Sep 17 00:00:00 2001 From: David Disseldorp Date: Thu, 19 Oct 2017 00:43:06 +0200 Subject: [PATCH 1/2] SMB: fix leak of validate negotiate info response buffer Fixes: ff1c038addc4 ("Check SMB3 dialects against downgrade attacks") Signed-off-by: David Disseldorp --- fs/cifs/smb2pdu.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 6f0e6343c15e..052ab5dee6b6 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -648,7 +648,7 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon) { int rc = 0; struct validate_negotiate_info_req vneg_inbuf; - struct validate_negotiate_info_rsp *pneg_rsp; + struct validate_negotiate_info_rsp *pneg_rsp = NULL; u32 rsplen; u32 inbuflen; /* max of 4 dialects */ @@ -728,7 +728,7 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon) /* relax check since Mac returns max bufsize allowed on ioctl */ if (rsplen > CIFSMaxBufSize) - return -EIO; + goto err_rsp_free; } /* check validate negotiate info response matches what we got earlier */ @@ -747,10 +747,13 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon) /* validate negotiate successful */ cifs_dbg(FYI, "validate negotiate info successful\n"); + kfree(pneg_rsp); return 0; vneg_out: cifs_dbg(VFS, "protocol revalidation - security settings mismatch\n"); +err_rsp_free: + kfree(pneg_rsp); return -EIO; } -- 2.13.6 From 82586902fb4467b068670b1a49cfa6f63bb33312 Mon Sep 17 00:00:00 2001 From: David Disseldorp Date: Thu, 19 Oct 2017 00:50:11 +0200 Subject: [PATCH 2/2] SMB: fix validate negotiate info uninitialised memory use An undersize validate negotiate info server response causes the client to use uninitialised memory for struct validate_negotiate_info_rsp comparisons of Dialect, SecurityMode and/or Capabilities members. Link: https://bugzilla.samba.org/show_bug.cgi?id=13092 Fixes: 7db0a6efdc3e ("SMB3: Work around mount failure when using SMB3 dialect to Macs") Signed-off-by: David Disseldorp --- fs/cifs/smb2pdu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 052ab5dee6b6..c836de2f79b2 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -727,7 +727,8 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon) rsplen); /* relax check since Mac returns max bufsize allowed on ioctl */ - if (rsplen > CIFSMaxBufSize) + if ((rsplen > CIFSMaxBufSize) + || (rsplen < sizeof(struct validate_negotiate_info_rsp))) goto err_rsp_free; } -- 2.13.6