From: Paulo Alcantara pc@manguebit.org

Some users and customers reported that their backup/copy tools started to fail when the directory being copied contained symlink targets that the client couldn't parse - even when those symlinks weren't followed.

Fix this by allowing lstat(2) and readlink(2) to succeed even when the client can't resolve the symlink target, restoring old behavior.

Cc: linux-cifs@vger.kernel.org Cc: stable@vger.kernel.org Reported-by: Remy Monsen monsen@monsen.cc Closes: https://lore.kernel.org/r/CAN+tdP7y=jqw3pBndZAGjQv0ObFq8Q=+PUDHgB36HdEz9QA6F... Reported-by: Pierguido Lambri plambri@redhat.com Fixes: 12b466eb52d9 ("cifs: Fix creating and resolving absolute NT-style symlinks") Signed-off-by: Paulo Alcantara (Red Hat) pc@manguebit.org Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: David Howells dhowells@redhat.com --- fs/smb/client/reparse.c | 20 ++++---------------- 1 file changed, 4 insertions(+), 16 deletions(-)

diff --git a/fs/smb/client/reparse.c b/fs/smb/client/reparse.c index 511611206dab..1c40e42e4d89 100644 --- a/fs/smb/client/reparse.c +++ b/fs/smb/client/reparse.c @@ -875,15 +875,8 @@ int smb2_parse_native_symlink(char **target, const char *buf, unsigned int len, abs_path += sizeof("\DosDevices\")-1; else if (strstarts(abs_path, "\GLOBAL??\")) abs_path += sizeof("\GLOBAL??\")-1; - else { - /* Unhandled absolute symlink, points outside of DOS/Win32 */ - cifs_dbg(VFS, - "absolute symlink '%s' cannot be converted from NT format " - "because points to unknown target\n", - smb_target); - rc = -EIO; - goto out; - } + else + goto out_unhandled_target;

/* Sometimes path separator after ?? is double backslash */ if (abs_path[0] == '\') @@ -910,13 +903,7 @@ int smb2_parse_native_symlink(char **target, const char *buf, unsigned int len, abs_path++; abs_path[0] = drive_letter; } else { - /* Unhandled absolute symlink. Report an error. */ - cifs_dbg(VFS, - "absolute symlink '%s' cannot be converted from NT format " - "because points to unknown target\n", - smb_target); - rc = -EIO; - goto out; + goto out_unhandled_target; }

abs_path_len = strlen(abs_path)+1; @@ -966,6 +953,7 @@ int smb2_parse_native_symlink(char **target, const char *buf, unsigned int len, * These paths have same format as Linux symlinks, so no * conversion is needed. */ +out_unhandled_target: linux_target = smb_target; smb_target = NULL; }