From: Paulo Alcantara <pc@xxxxxx>
commit 5c1acf3fe05ce443edba5e2110c9e581765f66a8 upstream.
The commit 315db9a05b7a ("cifs: fix leak in cifs_smb3_do_mount() ctx")
revealed an existing bug when mounting shares that contain a prefix
path or DFS links.
cifs_setup_volume_info() requires the @devname to contain the full
path (UNC + prefix) to update the fs context with the new UNC and
prepath values, however we were passing only the UNC
path (old_ctx->UNC) in @device thus discarding any prefix paths.
Instead of concatenating both old_ctx->{UNC,prepath} and pass it in
@devname, just keep the dup'ed values of UNC and prepath in
cifs_sb->ctx after calling smb3_fs_context_dup(), and fix
smb3_parse_devname() to correctly parse and not leak the new UNC and
prefix paths.
Cc: <stable@xxxxxxxxxxxxxxx> # v5.11+
Fixes: 315db9a05b7a ("cifs: fix leak in cifs_smb3_do_mount() ctx")
Signed-off-by: Paulo Alcantara (SUSE) <pc@xxxxxx>
Acked-by: David Disseldorp <ddiss@xxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/cifs/cifsfs.c | 8 +-------
fs/cifs/connect.c | 24 ++++++++++++++++++------
fs/cifs/fs_context.c | 4 ++++
3 files changed, 23 insertions(+), 13 deletions(-)
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -823,13 +823,7 @@ cifs_smb3_do_mount(struct file_system_ty
goto out;
}
- /* cifs_setup_volume_info->smb3_parse_devname() redups UNC & prepath */
- kfree(cifs_sb->ctx->UNC);
- cifs_sb->ctx->UNC = NULL;
- kfree(cifs_sb->ctx->prepath);
- cifs_sb->ctx->prepath = NULL;
-
- rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, old_ctx->UNC);
+ rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, NULL);
if (rc) {
root = ERR_PTR(rc);
goto out;
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3150,17 +3150,29 @@ out:
int
cifs_setup_volume_info(struct smb3_fs_context *ctx, const char *mntopts, const char *devname)
{
- int rc = 0;
+ int rc;
- smb3_parse_devname(devname, ctx);
+ if (devname) {
+ cifs_dbg(FYI, "%s: devname=%s\n", __func__, devname);
+ rc = smb3_parse_devname(devname, ctx);
+ if (rc) {
+ cifs_dbg(VFS, "%s: failed to parse %s: %d\n", __func__, devname, rc);
+ return rc;
+ }
+ }
if (mntopts) {
char *ip;
- cifs_dbg(FYI, "%s: mntopts=%s\n", __func__, mntopts);
rc = smb3_parse_opt(mntopts, "ip", &ip);
- if (!rc && !cifs_convert_address((struct sockaddr *)&ctx->dstaddr, ip,
- strlen(ip))) {
+ if (rc) {
+ cifs_dbg(VFS, "%s: failed to parse ip options: %d\n", __func__, rc);
+ return rc;
+ }
+
+ rc = cifs_convert_address((struct sockaddr *)&ctx->dstaddr, ip, strlen(ip));
+ kfree(ip);
+ if (!rc) {
cifs_dbg(VFS, "%s: failed to convert ip address\n", __func__);
return -EINVAL;
}
@@ -3180,7 +3192,7 @@ cifs_setup_volume_info(struct smb3_fs_co
return -EINVAL;
}
- return rc;
+ return 0;
}
static int
--- a/fs/cifs/fs_context.c
+++ b/fs/cifs/fs_context.c
@@ -473,6 +473,7 @@ smb3_parse_devname(const char *devname,
/* move "pos" up to delimiter or NULL */
pos += len;
+ kfree(ctx->UNC);
ctx->UNC = kstrndup(devname, pos - devname, GFP_KERNEL);
if (!ctx->UNC)
return -ENOMEM;
@@ -483,6 +484,9 @@ smb3_parse_devname(const char *devname,
if (*pos == '/' || *pos == '\\')
pos++;
+ kfree(ctx->prepath);
+ ctx->prepath = NULL;
+
/* If pos is NULL then no prepath */
if (!*pos)
return 0;
