[PATCH 1/2] smb: client: set correct id, uid and cruid for multiuser automounts

[PATCH 1/2] smb: client: set correct id, uid and cruid for multiuser automounts

[Paulo Alcantara]

When uid, gid and cruid are not specified, we need to set dynamically
set them into the filesystem context used for automounting otherwise
they'll end up reusing the values from the parent mount.

Fixes: 9fd29a5bae6e ("cifs: use fs_context for automounts")
Reported-by: Shane Nehring <snehring@iastate.edu>
Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2259257
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
---
 fs/smb/client/namespace.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/fs/smb/client/namespace.c b/fs/smb/client/namespace.c
index a6968573b775..4a517b280f2b 100644
--- a/fs/smb/client/namespace.c
+++ b/fs/smb/client/namespace.c
@@ -168,6 +168,21 @@ static char *automount_fullpath(struct dentry *dentry, void *page)
 	return s;
 }
 
+static void fs_context_set_ids(struct smb3_fs_context *ctx)
+{
+	kuid_t uid = current_fsuid();
+	kgid_t gid = current_fsgid();
+
+	if (ctx->multiuser) {
+		if (!ctx->uid_specified)
+			ctx->linux_uid = uid;
+		if (!ctx->gid_specified)
+			ctx->linux_gid = gid;
+	}
+	if (!ctx->cruid_specified)
+		ctx->cred_uid = uid;
+}
+
 /*
  * Create a vfsmount that we can automount
  */
@@ -205,6 +220,7 @@ static struct vfsmount *cifs_do_automount(struct path *path)
 	tmp.leaf_fullpath = NULL;
 	tmp.UNC = tmp.prepath = NULL;
 	tmp.dfs_root_ses = NULL;
+	fs_context_set_ids(&tmp);
 
 	rc = smb3_fs_context_dup(ctx, &tmp);
 	if (rc) {
-- 
2.43.0

[PATCH 2/2] smb: client: handle path separator of created SMB symlinks

[Paulo Alcantara]

Convert path separator to CIFS_DIR_SEP(cifs_sb) from symlink target
before sending it over the wire otherwise the created SMB symlink may
become innaccesible from server side.

Fixes: 514d793e27a3 ("smb: client: allow creating symlinks via reparse points")
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
---
 fs/smb/client/smb2ops.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index 6b3c384ead0d..4695433fcf39 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -5217,7 +5217,7 @@ static int smb2_create_reparse_symlink(const unsigned int xid,
 	struct inode *new;
 	struct kvec iov;
 	__le16 *path;
-	char *sym;
+	char *sym, sep = CIFS_DIR_SEP(cifs_sb);
 	u16 len, plen;
 	int rc = 0;
 
@@ -5231,7 +5231,8 @@ static int smb2_create_reparse_symlink(const unsigned int xid,
 		.symlink_target = sym,
 	};
 
-	path = cifs_convert_path_to_utf16(symname, cifs_sb);
+	convert_delimiter(sym, sep);
+	path = cifs_convert_path_to_utf16(sym, cifs_sb);
 	if (!path) {
 		rc = -ENOMEM;
 		goto out;
@@ -5254,7 +5255,10 @@ static int smb2_create_reparse_symlink(const unsigned int xid,
 	buf->PrintNameLength = cpu_to_le16(plen);
 	memcpy(buf->PathBuffer, path, plen);
 	buf->Flags = cpu_to_le32(*symname != '/' ? SYMLINK_FLAG_RELATIVE : 0);
+	if (*sym != sep)
+		buf->Flags = cpu_to_le32(SYMLINK_FLAG_RELATIVE);
 
+	convert_delimiter(sym, '/');
 	iov.iov_base = buf;
 	iov.iov_len = len;
 	new = smb2_get_reparse_inode(&data, inode->i_sb, xid,
-- 
2.43.0

Re: [PATCH 1/2] smb: client: set correct id, uid and cruid for multiuser automounts

[Steve French]

tentatively merged these two into cifs-2.6.git for-next pending review
and testing

On Sun, Feb 11, 2024 at 5:20 PM Paulo Alcantara <pc@manguebit.com> wrote:
>
> When uid, gid and cruid are not specified, we need to set dynamically
> set them into the filesystem context used for automounting otherwise
> they'll end up reusing the values from the parent mount.
>
> Fixes: 9fd29a5bae6e ("cifs: use fs_context for automounts")
> Reported-by: Shane Nehring <snehring@iastate.edu>
> Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2259257
> Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
> ---
>  fs/smb/client/namespace.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
>
> diff --git a/fs/smb/client/namespace.c b/fs/smb/client/namespace.c
> index a6968573b775..4a517b280f2b 100644
> --- a/fs/smb/client/namespace.c
> +++ b/fs/smb/client/namespace.c
> @@ -168,6 +168,21 @@ static char *automount_fullpath(struct dentry *dentry, void *page)
>         return s;
>  }
>
> +static void fs_context_set_ids(struct smb3_fs_context *ctx)
> +{
> +       kuid_t uid = current_fsuid();
> +       kgid_t gid = current_fsgid();
> +
> +       if (ctx->multiuser) {
> +               if (!ctx->uid_specified)
> +                       ctx->linux_uid = uid;
> +               if (!ctx->gid_specified)
> +                       ctx->linux_gid = gid;
> +       }
> +       if (!ctx->cruid_specified)
> +               ctx->cred_uid = uid;
> +}
> +
>  /*
>   * Create a vfsmount that we can automount
>   */
> @@ -205,6 +220,7 @@ static struct vfsmount *cifs_do_automount(struct path *path)
>         tmp.leaf_fullpath = NULL;
>         tmp.UNC = tmp.prepath = NULL;
>         tmp.dfs_root_ses = NULL;
> +       fs_context_set_ids(&tmp);
>
>         rc = smb3_fs_context_dup(ctx, &tmp);
>         if (rc) {
> --
> 2.43.0
>


-- 
Thanks,

Steve