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authorVivek Goyal <vgoyal@redhat.com>2020-10-09 14:15:11 -0400
committerMiklos Szeredi <mszeredi@redhat.com>2020-11-11 17:22:33 +0100
commit643a666a89c358ef588d2b3ef9f2dc1efc421e61 (patch)
tree6e9065257d8d01110e3aa26e8cfc5a87295b32dd /fs/fuse
parent8981bdfda7445af5d5a8c277c923bf91873a0c98 (diff)
downloadlinux-643a666a89c358ef588d2b3ef9f2dc1efc421e61.tar.bz2
fuse: add a flag FUSE_OPEN_KILL_SUIDGID for open() request
With FUSE_HANDLE_KILLPRIV_V2 support, server will need to kill suid/sgid/ security.capability on open(O_TRUNC), if server supports FUSE_ATOMIC_O_TRUNC. But server needs to kill suid/sgid only if caller does not have CAP_FSETID. Given server does not have this information, client needs to send this info to server. So add a flag FUSE_OPEN_KILL_SUIDGID to fuse_open_in request which tells server to kill suid/sgid (only if group execute is set). This flag is added to the FUSE_OPEN request, as well as the FUSE_CREATE request if the create was non-exclusive, since that might result in an existing file being opened/truncated. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/fuse')
-rw-r--r--fs/fuse/dir.c6
-rw-r--r--fs/fuse/file.c6
2 files changed, 12 insertions, 0 deletions
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 778367d125f9..5d43af1169b7 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -541,6 +541,12 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry,
inarg.flags = flags;
inarg.mode = mode;
inarg.umask = current_umask();
+
+ if (fm->fc->handle_killpriv_v2 && (flags & O_TRUNC) &&
+ !(flags & O_EXCL) && !capable(CAP_FSETID)) {
+ inarg.open_flags |= FUSE_OPEN_KILL_SUIDGID;
+ }
+
args.opcode = FUSE_CREATE;
args.nodeid = get_node_id(dir);
args.in_numargs = 2;
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index aa0a44f7028f..349885353036 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -42,6 +42,12 @@ static int fuse_send_open(struct fuse_mount *fm, u64 nodeid, struct file *file,
inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
if (!fm->fc->atomic_o_trunc)
inarg.flags &= ~O_TRUNC;
+
+ if (fm->fc->handle_killpriv_v2 &&
+ (inarg.flags & O_TRUNC) && !capable(CAP_FSETID)) {
+ inarg.open_flags |= FUSE_OPEN_KILL_SUIDGID;
+ }
+
args.opcode = opcode;
args.nodeid = nodeid;
args.in_numargs = 1;