Attachment 13305 Details for Bug 12860 – Proposed regression fix for master

[patch] Proposed regression fix for master

0001-s3-smbd-fix-regression-with-non-wide-symlinks-to-dir.patch (text/plain), 2.18 KB, created by Daniel Kobras (dead mail address) on 2017-06-23 13:51:37 UTC

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Creator: Daniel Kobras (dead mail address)

Created: 2017-06-23 13:51:37 UTC

Size: 2.18 KB

patch

obsolete

>From a8f9b969ce76037582dd70d078578b6d5d5d109f Mon Sep 17 00:00:00 2001
>From: Daniel Kobras <d.kobras@science-computing.de>
>Date: Fri, 23 Jun 2017 15:39:21 +0200
>Subject: [PATCH] s3: smbd: fix regression with non-wide symlinks to
> directories
>
>The errno set by open() is ambiguous when called with flags O_NOFOLLOW and
>O_DIRECTORY on a symlink. With ELOOP, we know for certain that we've tried to
>open a symlink. With ENOTDIR, we might have hit a symlink, and need to perform
>further checks to be sure. Adjust non_widelink_open() accordingly. This fixes
>a regression where symlinks to directories within the same share were no
>longer followed for some call paths on systems returning ENOTDIR in the above
>case.
>
>BUG: https://bugzilla.samba.org/show_bug.cgi?id=12860
>
>Signed-off-by: Daniel Kobras <d.kobras@science-computing.de>
>---
> source3/smbd/open.c | 19 ++++++++++++++++++-
> 1 file changed, 18 insertions(+), 1 deletion(-)
>
>diff --git a/source3/smbd/open.c b/source3/smbd/open.c
>index e68e2ac..89c0a74 100644
>--- a/source3/smbd/open.c
>+++ b/source3/smbd/open.c
>@@ -581,7 +581,15 @@ static int non_widelink_open(struct connection_struct *conn,
> 
> 	if (fd == -1) {
> 		saved_errno = link_errno_convert(errno);
>-		if (saved_errno == ELOOP) {
>+
>+		/*
>+		 * Trying to open a symlink to a directory with O_NOFOLLOW and
>+		 * O_DIRECTORY can return either of ELOOP and ENOTDIR. So ENOTDIR really means:
>+		 * might be a symlink, but we're not sure. In this case, we just assume there's
>+		 * a symlink. If we were wrong, process_symlink_open() will return EINVAL. We
>+		 * check this below, and fall back to returning the initial saved_errno.
>+		 */
>+		if (saved_errno == ELOOP || saved_errno == ENOTDIR) {
> 			if (fsp->posix_flags & FSP_POSIX_FLAGS_OPEN) {
> 				/* Never follow symlinks on posix open. */
> 				goto out;
>@@ -602,6 +610,15 @@ static int non_widelink_open(struct connection_struct *conn,
> 					mode,
> 					link_depth);
> 			if (fd == -1) {
>+				/*
>+				 * O_DIRECTORY on neither a directory, nor a
>+				 * symlink. Just return errno from initial
>+				 * open()
>+				 */
>+				if (saved_errno == ENOTDIR &&
>+						errno == EINVAL) {
>+					goto out;
>+				}
> 				saved_errno =
> 					link_errno_convert(errno);
> 			}
>-- 
>2.9.0
>

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