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173 lines
4.5 KiB
Diff
173 lines
4.5 KiB
Diff
From eb27f9b7bf9c1dc902d9545eecf805831bd4e46c Mon Sep 17 00:00:00 2001
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From: Jeremy Allison <jra@samba.org>
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Date: Tue, 5 Jan 2016 11:18:12 -0800
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Subject: [PATCH 1/8] CVE-2015-7560: s3: smbd: Add refuse_symlink() function
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that can be used to prevent operations on a symlink.
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BUG: https://bugzilla.samba.org/show_bug.cgi?id=11648
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Signed-off-by: Jeremy Allison <jra@samba.org>
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Reviewed-by: Michael Adam <obnox@samba.org>
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---
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source3/smbd/trans2.c | 28 ++++++++++++++++++++++++++++
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1 file changed, 28 insertions(+)
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--- a/source3/smbd/trans2.c
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+++ b/source3/smbd/trans2.c
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@@ -51,6 +51,34 @@ static char *store_file_unix_basic_info2
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files_struct *fsp,
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const SMB_STRUCT_STAT *psbuf);
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+/****************************************************************************
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+ Check if an open file handle or pathname is a symlink.
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+****************************************************************************/
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+
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+static NTSTATUS refuse_symlink(connection_struct *conn,
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+ const files_struct *fsp,
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+ const char *name)
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+{
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+ SMB_STRUCT_STAT sbuf;
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+ const SMB_STRUCT_STAT *pst = NULL;
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+
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+ if (fsp) {
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+ pst = &fsp->fsp_name->st;
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+ } else {
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+ int ret = vfs_stat_smb_fname(conn,
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+ name,
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+ &sbuf);
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+ if (ret == -1) {
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+ return map_nt_error_from_unix(errno);
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+ }
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+ pst = &sbuf;
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+ }
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+ if (S_ISLNK(pst->st_ex_mode)) {
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+ return NT_STATUS_ACCESS_DENIED;
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+ }
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+ return NT_STATUS_OK;
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+}
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+
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/********************************************************************
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Roundup a value to the nearest allocation roundup size boundary.
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Only do this for Windows clients.
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@@ -181,12 +209,22 @@ NTSTATUS get_ea_names_from_file(TALLOC_C
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char **names, **tmp;
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size_t num_names;
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ssize_t sizeret = -1;
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+ NTSTATUS status;
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+
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+ if (pnames) {
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+ *pnames = NULL;
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+ }
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+ *pnum_names = 0;
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if (!lp_ea_support(SNUM(conn))) {
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- if (pnames) {
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- *pnames = NULL;
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- }
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- *pnum_names = 0;
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+ return NT_STATUS_OK;
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+ }
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+
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+ status = refuse_symlink(conn, fsp, fname);
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+ if (!NT_STATUS_IS_OK(status)) {
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+ /*
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+ * Just return no EA's on a symlink.
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+ */
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return NT_STATUS_OK;
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}
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@@ -236,10 +274,6 @@ NTSTATUS get_ea_names_from_file(TALLOC_C
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if (sizeret == 0) {
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TALLOC_FREE(names);
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- if (pnames) {
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- *pnames = NULL;
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- }
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- *pnum_names = 0;
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return NT_STATUS_OK;
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}
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@@ -550,6 +584,7 @@ NTSTATUS set_ea(connection_struct *conn,
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const struct smb_filename *smb_fname, struct ea_list *ea_list)
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{
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char *fname = NULL;
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+ NTSTATUS status;
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if (!lp_ea_support(SNUM(conn))) {
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return NT_STATUS_EAS_NOT_SUPPORTED;
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@@ -559,6 +594,12 @@ NTSTATUS set_ea(connection_struct *conn,
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return NT_STATUS_ACCESS_DENIED;
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}
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+ status = refuse_symlink(conn, fsp, smb_fname->base_name);
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+ if (!NT_STATUS_IS_OK(status)) {
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+ return status;
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+ }
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+
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+
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/* For now setting EAs on streams isn't supported. */
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fname = smb_fname->base_name;
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@@ -4931,6 +4972,13 @@ NTSTATUS smbd_do_qfilepathinfo(connectio
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uint16 num_file_acls = 0;
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uint16 num_def_acls = 0;
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+ status = refuse_symlink(conn,
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+ fsp,
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+ smb_fname->base_name);
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+ if (!NT_STATUS_IS_OK(status)) {
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+ return status;
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+ }
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+
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if (fsp && fsp->fh->fd != -1) {
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file_acl = SMB_VFS_SYS_ACL_GET_FD(fsp);
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} else {
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@@ -6452,6 +6500,7 @@ static NTSTATUS smb_set_posix_acl(connec
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uint16 num_def_acls;
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bool valid_file_acls = True;
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bool valid_def_acls = True;
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+ NTSTATUS status;
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if (total_data < SMB_POSIX_ACL_HEADER_SIZE) {
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return NT_STATUS_INVALID_PARAMETER;
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@@ -6479,6 +6528,11 @@ static NTSTATUS smb_set_posix_acl(connec
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return NT_STATUS_INVALID_PARAMETER;
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}
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+ status = refuse_symlink(conn, fsp, smb_fname->base_name);
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+ if (!NT_STATUS_IS_OK(status)) {
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+ return status;
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+ }
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+
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DEBUG(10,("smb_set_posix_acl: file %s num_file_acls = %u, num_def_acls = %u\n",
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smb_fname ? smb_fname_str_dbg(smb_fname) : fsp_str_dbg(fsp),
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(unsigned int)num_file_acls,
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--- a/source3/smbd/nttrans.c
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+++ b/source3/smbd/nttrans.c
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@@ -877,6 +877,12 @@ NTSTATUS set_sd(files_struct *fsp, struc
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return NT_STATUS_OK;
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}
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+ if (S_ISLNK(fsp->fsp_name->st.st_ex_mode)) {
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+ DEBUG(10, ("ACL set on symlink %s denied.\n",
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+ fsp_str_dbg(fsp)));
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+ return NT_STATUS_ACCESS_DENIED;
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+ }
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+
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if (psd->owner_sid == NULL) {
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security_info_sent &= ~SECINFO_OWNER;
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}
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@@ -1925,6 +1931,12 @@ NTSTATUS smbd_do_query_security_desc(con
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return NT_STATUS_ACCESS_DENIED;
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}
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+ if (S_ISLNK(fsp->fsp_name->st.st_ex_mode)) {
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+ DEBUG(10, ("ACL get on symlink %s denied.\n",
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+ fsp_str_dbg(fsp)));
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+ return NT_STATUS_ACCESS_DENIED;
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+ }
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+
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if (security_info_wanted & (SECINFO_DACL|SECINFO_OWNER|
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SECINFO_GROUP|SECINFO_SACL)) {
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/* Don't return SECINFO_LABEL if anything else was
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