Attachment 13456 Details for Bug 12944 – Patch for 4.6 backported from master

[patch] Patch for 4.6 backported from master

bug12944-v46.patch (text/plain), 7.84 KB, created by Ralph Böhme on 2017-08-09 08:10:40 UTC

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Creator: Ralph Böhme

Created: 2017-08-09 08:10:40 UTC

Size: 7.84 KB

patch

obsolete

>From f1d4282babaadaeceb44c1cf4423717030cb6f0c Mon Sep 17 00:00:00 2001
>From: Ralph Boehme <slow@samba.org>
>Date: Thu, 8 Jun 2017 19:05:48 +0200
>Subject: [PATCH 1/3] s3/smbd: handling of failed DOS attributes reading
>
>Only fall back to using UNIX modes if we get NOT_IMPLEMENTED. This is
>exactly what we already do when setting DOS attributes.
>
>Bug: https://bugzilla.samba.org/show_bug.cgi?id=12944
>
>Signed-off-by: Ralph Boehme <slow@samba.org>
>Reviewed-by: Christof Schmitt <cs@samba.org>
>(cherry picked from commit 9de1411d9e7c7ac3da544345d4dea7fd73dff01b)
>---
> source3/smbd/dosmode.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
>diff --git a/source3/smbd/dosmode.c b/source3/smbd/dosmode.c
>index 1789b55..c5a1f85 100644
>--- a/source3/smbd/dosmode.c
>+++ b/source3/smbd/dosmode.c
>@@ -622,7 +622,12 @@ uint32_t dos_mode(connection_struct *conn, struct smb_filename *smb_fname)
> 	/* Get the DOS attributes via the VFS if we can */
> 	status = SMB_VFS_GET_DOS_ATTRIBUTES(conn, smb_fname, &result);
> 	if (!NT_STATUS_IS_OK(status)) {
>-		result |= dos_mode_from_sbuf(conn, smb_fname);
>+		/*
>+		 * Only fall back to using UNIX modes if we get NOT_IMPLEMENTED.
>+		 */
>+		if (NT_STATUS_EQUAL(status, NT_STATUS_NOT_IMPLEMENTED)) {
>+			result |= dos_mode_from_sbuf(conn, smb_fname);
>+		}
> 	}
> 
> 	if (conn->fs_capabilities & FILE_FILE_COMPRESSION) {
>-- 
>2.9.4
>
>
>From a6b47ece98bc40e2cea33da5949802367739585a Mon Sep 17 00:00:00 2001
>From: Ralph Boehme <slow@samba.org>
>Date: Thu, 8 Jun 2017 19:10:20 +0200
>Subject: [PATCH 2/3] s3/smbd: handle EACCES when fetching DOS attributes from
> xattr
>
>When trying to fetch the DOS attributes xattr via SMB_VFS_GETXATTR() if
>the filesystem doesn't grant read access to the file the xattr read
>request fails with EACCESS.
>
>But according to MS-FSA 2.1.5.1.2.1 "Algorithm to Check Access to an
>Existing File" FILE_LIST_DIRECTORY on a directory implies
>FILE_READ_ATTRIBUTES for directory entries.
>
>So if the user can open the parent directory for reading this implies
>FILE_LIST_DIRECTORY and we can safely call SMB_VFS_GETXATTR() as root,
>ensuring we can read the DOS attributes xattr.
>
>Bug: https://bugzilla.samba.org/show_bug.cgi?id=12944
>
>Signed-off-by: Ralph Boehme <slow@samba.org>
>Reviewed-by: Christof Schmitt <cs@samba.org>
>(backported from commit c54fcb7cbd0de244eed4134e877da6e9c16e7aab)
>---
> source3/smbd/dosmode.c | 36 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 36 insertions(+)
>
>diff --git a/source3/smbd/dosmode.c b/source3/smbd/dosmode.c
>index c5a1f85..df75542 100644
>--- a/source3/smbd/dosmode.c
>+++ b/source3/smbd/dosmode.c
>@@ -281,6 +281,42 @@ NTSTATUS get_ea_dos_attribute(connection_struct *conn,
> 	sizeret = SMB_VFS_GETXATTR(conn, smb_fname->base_name,
> 				   SAMBA_XATTR_DOS_ATTRIB, attrstr,
> 				   sizeof(attrstr));
>+	if (sizeret == -1 && errno == EACCES) {
>+		int saved_errno = 0;
>+
>+		/*
>+		 * According to MS-FSA 2.1.5.1.2.1 "Algorithm to Check Access to
>+		 * an Existing File" FILE_LIST_DIRECTORY on a directory implies
>+		 * FILE_READ_ATTRIBUTES for directory entries. Being able to
>+		 * stat() a file implies FILE_LIST_DIRECTORY for the directory
>+		 * containing the file.
>+		 */
>+
>+		if (!VALID_STAT(smb_fname->st)) {
>+			/*
>+			 * Safety net: dos_mode() already checks this, but as we
>+			 * become root based on this, add an additional layer of
>+			 * defense.
>+			 */
>+			DBG_ERR("Rejecting root override, invalid stat [%s]\n",
>+				smb_fname_str_dbg(smb_fname));
>+			return NT_STATUS_ACCESS_DENIED;
>+		}
>+
>+		become_root();
>+		sizeret = SMB_VFS_GETXATTR(conn, smb_fname->base_name,
>+					   SAMBA_XATTR_DOS_ATTRIB,
>+					   attrstr,
>+					   sizeof(attrstr));
>+		if (sizeret == -1) {
>+			saved_errno = errno;
>+		}
>+		unbecome_root();
>+
>+		if (saved_errno != 0) {
>+			errno = saved_errno;
>+		}
>+	}
> 	if (sizeret == -1) {
> 		DBG_INFO("Cannot get attribute "
> 			 "from EA on file %s: Error = %s\n",
>-- 
>2.9.4
>
>
>From e42abb292715d7f0ffe59a2b9aa26707b01bdadf Mon Sep 17 00:00:00 2001
>From: Ralph Boehme <slow@samba.org>
>Date: Thu, 8 Jun 2017 19:18:36 +0200
>Subject: [PATCH 3/3] vfs_gpfs: handle EACCES when fetching DOS attributes from
> xattr
>MIME-Version: 1.0
>Content-Type: text/plain; charset=UTF-8
>Content-Transfer-Encoding: 8bit
>
>When trying to fetch the DOS attributes via gpfswrap_get_winattrs_path()
>if the filesystem doesn't grant READ_ATTR to the file the function fails
>with EACCESS.
>
>But according to MS-FSA 2.1.5.1.2.1 "Algorithm to Check Access to an
>Existing File" FILE_LIST_DIRECTORY on a directory implies
>FILE_READ_ATTRIBUTES for directory entries.
>
>So if the user can open the parent directory for reading this implies
>FILE_LIST_DIRECTORY and we can safely call gpfswrap_get_winattrs_path()
>with DAC_OVERRIDE_CAPABILITY.
>
>Bug: https://bugzilla.samba.org/show_bug.cgi?id=12944
>
>Signed-off-by: Ralph Boehme <slow@samba.org>
>Reviewed-by: Christof Schmitt <cs@samba.org>
>
>Autobuild-User(master): Ralph BÃ¶hme <slow@samba.org>
>Autobuild-Date(master): Wed Aug  9 01:21:14 CEST 2017 on sn-devel-144
>
>(cherry picked from commit 62d73f5b936550d623ef4f31c7438ac3c90105b9)
>---
> source3/modules/vfs_gpfs.c | 69 +++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 68 insertions(+), 1 deletion(-)
>
>diff --git a/source3/modules/vfs_gpfs.c b/source3/modules/vfs_gpfs.c
>index f7434c9..565798e 100644
>--- a/source3/modules/vfs_gpfs.c
>+++ b/source3/modules/vfs_gpfs.c
>@@ -1535,6 +1535,47 @@ static unsigned int vfs_gpfs_dosmode_to_winattrs(uint32_t dosmode)
> 	return winattrs;
> }
> 
>+static int get_dos_attr_with_capability(struct smb_filename *smb_fname,
>+					struct gpfs_winattr *attr)
>+{
>+	int saved_errno = 0;
>+	int ret;
>+
>+	/*
>+	 * According to MS-FSA 2.1.5.1.2.1 "Algorithm to Check Access to an
>+	 * Existing File" FILE_LIST_DIRECTORY on a directory implies
>+	 * FILE_READ_ATTRIBUTES for directory entries. Being able to stat() a
>+	 * file implies FILE_LIST_DIRECTORY for the directory containing the
>+	 * file.
>+	 */
>+
>+	if (!VALID_STAT(smb_fname->st)) {
>+		/*
>+		 * Safety net: dos_mode() already checks this, but as we set
>+		 * DAC_OVERRIDE_CAPABILITY based on this, add an additional
>+		 * layer of defense.
>+		 */
>+		DBG_ERR("Rejecting DAC override, invalid stat [%s]\n",
>+			smb_fname_str_dbg(smb_fname));
>+		errno = EACCES;
>+		return -1;
>+	}
>+
>+	set_effective_capability(DAC_OVERRIDE_CAPABILITY);
>+
>+	ret = gpfswrap_get_winattrs_path(smb_fname->base_name, attr);
>+	if (ret == -1) {
>+		saved_errno = errno;
>+	}
>+
>+	drop_effective_capability(DAC_OVERRIDE_CAPABILITY);
>+
>+	if (saved_errno != 0) {
>+		errno = saved_errno;
>+	}
>+	return ret;
>+}
>+
> static NTSTATUS vfs_gpfs_get_dos_attributes(struct vfs_handle_struct *handle,
> 					    struct smb_filename *smb_fname,
> 					    uint32_t *dosmode)
>@@ -1557,7 +1598,9 @@ static NTSTATUS vfs_gpfs_get_dos_attributes(struct vfs_handle_struct *handle,
> 		return SMB_VFS_NEXT_GET_DOS_ATTRIBUTES(handle, smb_fname,
> 						       dosmode);
> 	}
>-
>+	if (ret == -1 && errno == EACCES) {
>+		ret = get_dos_attr_with_capability(smb_fname, &attrs);
>+	}
> 	if (ret == -1) {
> 		DBG_WARNING("Getting winattrs failed for %s: %s\n",
> 			    smb_fname->base_name, strerror(errno));
>@@ -1593,6 +1636,30 @@ static NTSTATUS vfs_gpfs_fget_dos_attributes(struct vfs_handle_struct *handle,
> 		return SMB_VFS_NEXT_FGET_DOS_ATTRIBUTES(handle, fsp, dosmode);
> 	}
> 
>+	if (ret == -1 && errno == EACCES) {
>+		int saved_errno = 0;
>+
>+		/*
>+		 * According to MS-FSA 2.1.5.1.2.1 "Algorithm to Check Access to
>+		 * an Existing File" FILE_LIST_DIRECTORY on a directory implies
>+		 * FILE_READ_ATTRIBUTES for directory entries. Being able to
>+		 * open a file implies FILE_LIST_DIRECTORY.
>+		 */
>+
>+		set_effective_capability(DAC_OVERRIDE_CAPABILITY);
>+
>+		ret = gpfswrap_get_winattrs(fsp->fh->fd, &attrs);
>+		if (ret == -1) {
>+			saved_errno = errno;
>+		}
>+
>+		drop_effective_capability(DAC_OVERRIDE_CAPABILITY);
>+
>+		if (saved_errno != 0) {
>+			errno = saved_errno;
>+		}
>+	}
>+
> 	if (ret == -1) {
> 		DBG_WARNING("Getting winattrs failed for %s: %s\n",
> 			    fsp->fsp_name->base_name, strerror(errno));
>-- 
>2.9.4
>

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Attachments on bug 12944: 13455 | 13456 | 13457