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authorLinus Torvalds <torvalds@linux-foundation.org>2024-05-13 11:40:06 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2024-05-13 11:40:06 -0700
commit1b0aabcc9a35e729a6c7ce71e725fd63513b35de (patch)
tree888fa09f657757fd848ae8bed129df169d02d194 /fs/namei.c
parentc117a437f25db7d88831816cb3a40ee556535ce2 (diff)
parentda0e01cc7079124cb1e86a2c35dd90ba12897e1a (diff)
Merge tag 'vfs-6.10.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull misc vfs updates from Christian Brauner: "This contains the usual miscellaneous features, cleanups, and fixes for vfs and individual fses. Features: - Free up FMODE_* bits. I've freed up bits 6, 7, 8, and 24. That means we now have six free FMODE_* bits in total (but bit #6 already got used for FMODE_WRITE_RESTRICTED) - Add FOP_HUGE_PAGES flag (follow-up to FMODE_* cleanup) - Add fd_raw cleanup class so we can make use of automatic cleanup provided by CLASS(fd_raw, f)(fd) for O_PATH fds as well - Optimize seq_puts() - Simplify __seq_puts() - Add new anon_inode_getfile_fmode() api to allow specifying f_mode instead of open-coding it in multiple places - Annotate struct file_handle with __counted_by() and use struct_size() - Warn in get_file() whether f_count resurrection from zero is attempted (epoll/drm discussion) - Folio-sophize aio - Export the subvolume id in statx() for both btrfs and bcachefs - Relax linkat(AT_EMPTY_PATH) requirements - Add F_DUPFD_QUERY fcntl() allowing to compare two file descriptors for dup*() equality replacing kcmp() Cleanups: - Compile out swapfile inode checks when swap isn't enabled - Use (1 << n) notation for FMODE_* bitshifts for clarity - Remove redundant variable assignment in fs/direct-io - Cleanup uses of strncpy in orangefs - Speed up and cleanup writeback - Move fsparam_string_empty() helper into header since it's currently open-coded in multiple places - Add kernel-doc comments to proc_create_net_data_write() - Don't needlessly read dentry->d_flags twice Fixes: - Fix out-of-range warning in nilfs2 - Fix ecryptfs overflow due to wrong encryption packet size calculation - Fix overly long line in xfs file_operations (follow-up to FMODE_* cleanup) - Don't raise FOP_BUFFER_{R,W}ASYNC for directories in xfs (follow-up to FMODE_* cleanup) - Don't call xfs_file_open from xfs_dir_open (follow-up to FMODE_* cleanup) - Fix stable offset api to prevent endless loops - Fix afs file server rotations - Prevent xattr node from overflowing the eraseblock in jffs2 - Move fdinfo PTRACE_MODE_READ procfs check into the .permission() operation instead of .open() operation since this caused userspace regressions" * tag 'vfs-6.10.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (39 commits) afs: Fix fileserver rotation getting stuck selftests: add F_DUPDFD_QUERY selftests fcntl: add F_DUPFD_QUERY fcntl() file: add fd_raw cleanup class fs: WARN when f_count resurrection is attempted seq_file: Simplify __seq_puts() seq_file: Optimize seq_puts() proc: Move fdinfo PTRACE_MODE_READ check into the inode .permission operation fs: Create anon_inode_getfile_fmode() xfs: don't call xfs_file_open from xfs_dir_open xfs: drop fop_flags for directories xfs: fix overly long line in the file_operations shmem: Fix shmem_rename2() libfs: Add simple_offset_rename() API libfs: Fix simple_offset_rename_exchange() jffs2: prevent xattr node from overflowing the eraseblock vfs, swap: compile out IS_SWAPFILE() on swapless configs vfs: relax linkat() AT_EMPTY_PATH - aka flink() - requirements fs/direct-io: remove redundant assignment to variable retval fs/dcache: Re-use value stored to dentry->d_flags instead of re-reading ...
Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c19
1 files changed, 13 insertions, 6 deletions
diff --git a/fs/namei.c b/fs/namei.c
index c5b2a25be7d0..cb5dde0e309f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2422,6 +2422,14 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
if (!f.file)
return ERR_PTR(-EBADF);
+ if (flags & LOOKUP_LINKAT_EMPTY) {
+ if (f.file->f_cred != current_cred() &&
+ !ns_capable(f.file->f_cred->user_ns, CAP_DAC_READ_SEARCH)) {
+ fdput(f);
+ return ERR_PTR(-ENOENT);
+ }
+ }
+
dentry = f.file->f_path.dentry;
if (*s && unlikely(!d_can_lookup(dentry))) {
@@ -4641,14 +4649,13 @@ int do_linkat(int olddfd, struct filename *old, int newdfd,
goto out_putnames;
}
/*
- * To use null names we require CAP_DAC_READ_SEARCH
+ * To use null names we require CAP_DAC_READ_SEARCH or
+ * that the open-time creds of the dfd matches current.
* This ensures that not everyone will be able to create
- * handlink using the passed filedescriptor.
+ * a hardlink using the passed file descriptor.
*/
- if (flags & AT_EMPTY_PATH && !capable(CAP_DAC_READ_SEARCH)) {
- error = -ENOENT;
- goto out_putnames;
- }
+ if (flags & AT_EMPTY_PATH)
+ how |= LOOKUP_LINKAT_EMPTY;
if (flags & AT_SYMLINK_FOLLOW)
how |= LOOKUP_FOLLOW;