Cited from commit message of original patch [1]:
> One use case will be setfiles(8) setting SELinux file contexts
> ("security.selinux") without race conditions and without a file
> descriptor opened with read access requiring SELinux read permission.
Also, generally all *at() syscalls operate on O_PATH fds, unlike
f*() ones. Yet the O_PATH fds are rejected by *xattrat() syscalls
in the final version merged into tree. Instead, let's switch things
to CLASS(fd_raw).
Note that there's one side effect: f*xattr() starts to work with
O_PATH fds too. It's not clear to me whether this is desirable
(e.g. fstat() accepts O_PATH fds as an outlier).
[1] https://lore.kernel.org/all/20240426162042.191916-1-cgoettsche@xxxxxxxxxxxxx/
Fixes: 6140be90ec70 ("fs/xattr: add *at family syscalls")
Signed-off-by: Mike Yuan <me@xxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christian Göttsche <cgzones@xxxxxxxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
---
fs/xattr.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/xattr.c b/fs/xattr.c
index 02bee149ad96..15df71e56187 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -704,7 +704,7 @@ static int path_setxattrat(int dfd, const char __user *pathname,
filename = getname_maybe_null(pathname, at_flags);
if (!filename) {
- CLASS(fd, f)(dfd);
+ CLASS(fd_raw, f)(dfd);
if (fd_empty(f))
error = -EBADF;
else
@@ -848,7 +848,7 @@ static ssize_t path_getxattrat(int dfd, const char __user *pathname,
filename = getname_maybe_null(pathname, at_flags);
if (!filename) {
- CLASS(fd, f)(dfd);
+ CLASS(fd_raw, f)(dfd);
if (fd_empty(f))
return -EBADF;
return file_getxattr(fd_file(f), &ctx);
@@ -978,7 +978,7 @@ static ssize_t path_listxattrat(int dfd, const char __user *pathname,
filename = getname_maybe_null(pathname, at_flags);
if (!filename) {
- CLASS(fd, f)(dfd);
+ CLASS(fd_raw, f)(dfd);
if (fd_empty(f))
return -EBADF;
return file_listxattr(fd_file(f), list, size);
@@ -1079,7 +1079,7 @@ static int path_removexattrat(int dfd, const char __user *pathname,
filename = getname_maybe_null(pathname, at_flags);
if (!filename) {
- CLASS(fd, f)(dfd);
+ CLASS(fd_raw, f)(dfd);
if (fd_empty(f))
return -EBADF;
return file_removexattr(fd_file(f), &kname);
base-commit: a86bf2283d2c9769205407e2b54777c03d012939
--
2.48.1
