This allows xattr ops on symlink/special files referenced by an O_PATH
descriptor without having to play games with /proc/self/fd/NN (which
doesn't work for symlinks anyway).
This capability is the same as would be given by introducing ...at()
variants with an AT_EMPTY_PATH argument. Looking at getattr/setattr type
syscalls, this is allowed for fstatat() and fchownat(), but not for
fchmodat() and utimensat(). What's the logic?
While this carries a minute risk of someone relying on the property of
xattr syscalls rejecting O_PATH descriptors, it saves the trouble of
introducing another set of syscalls.
Only file->f_path and file->f_inode are accessed in these functions.
Current versions return EBADF, hence easy to detect the presense of this
feature and fall back in case it's missing.
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
---
fs/xattr.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/xattr.c b/fs/xattr.c
index e13265e65871..7080bb4f3f14 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -495,7 +495,7 @@ SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname,
SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
const void __user *,value, size_t, size, int, flags)
{
- struct fd f = fdget(fd);
+ struct fd f = fdget_raw(fd);
int error = -EBADF;
if (!f.file)
@@ -587,7 +587,7 @@ SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname,
SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
void __user *, value, size_t, size)
{
- struct fd f = fdget(fd);
+ struct fd f = fdget_raw(fd);
ssize_t error = -EBADF;
if (!f.file)
@@ -662,7 +662,7 @@ SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list,
SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size)
{
- struct fd f = fdget(fd);
+ struct fd f = fdget_raw(fd);
ssize_t error = -EBADF;
if (!f.file)
@@ -727,7 +727,7 @@ SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname,
SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name)
{
- struct fd f = fdget(fd);
+ struct fd f = fdget_raw(fd);
int error = -EBADF;
if (!f.file)
--
2.21.1
