Unfortunately we can't kfree() the UNC and prefix paths in
cifs_smb3_do_mount() because they could have come from a chased DFS
referral (automount) and we rely on the new values set in cifs_sb->ctx
prior to calling cifs_mount().
Instead, fix smb3_parse_devname() to not leak the UNC and prefix paths
when parsing new share 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>
---
fs/cifs/cifsfs.c | 6 ------
fs/cifs/connect.c | 10 +++++++---
fs/cifs/fs_context.c | 2 ++
3 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 8a6894577697..bfe98136f9c1 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -863,12 +863,6 @@ cifs_smb3_do_mount(struct file_system_type *fs_type,
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);
if (rc) {
root = ERR_PTR(rc);
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index becd5f807787..ee4a92cbcb29 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3159,9 +3159,13 @@ static int do_dfs_failover(const char *path, const char *full_path, struct cifs_
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);
+ 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;
@@ -3189,7 +3193,7 @@ cifs_setup_volume_info(struct smb3_fs_context *ctx, const char *mntopts, const c
return -EINVAL;
}
- return rc;
+ return 0;
}
static int
diff --git a/fs/cifs/fs_context.c b/fs/cifs/fs_context.c
index 1d6e0e15b034..b502a44e15a1 100644
--- a/fs/cifs/fs_context.c
+++ b/fs/cifs/fs_context.c
@@ -476,6 +476,7 @@ smb3_parse_devname(const char *devname, struct smb3_fs_context *ctx)
/* 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;
@@ -490,6 +491,7 @@ smb3_parse_devname(const char *devname, struct smb3_fs_context *ctx)
if (!*pos)
return 0;
+ kfree(ctx->prepath);
ctx->prepath = kstrdup(pos, GFP_KERNEL);
if (!ctx->prepath)
return -ENOMEM;
--
2.31.1
