If userspace passes an nfs_mount_data struct in the data argument of
mount(2), then nfs23_parse_monolithic() or nfs4_parse_monolithic()
will allocate memory for ctx->nfs_server.hostname. This needs to be
freed in nfs_parse_source(), which also allocates memory for
ctx->nfs_server.hostname, otherwise a leak will occur.
Reported-by: syzbot+193c375dcddb4f345091@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: f2aedb713c28 ("NFS: Add fs_context support.")
Signed-off-by: Scott Mayhew <smayhew@xxxxxxxxxx>
---
fs/nfs/fs_context.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/nfs/fs_context.c b/fs/nfs/fs_context.c
index b616263b0eb6..e113fcb4bb4c 100644
--- a/fs/nfs/fs_context.c
+++ b/fs/nfs/fs_context.c
@@ -832,6 +832,8 @@ static int nfs_parse_source(struct fs_context *fc,
if (len > maxnamlen)
goto out_hostname;
+ kfree(ctx->nfs_server.hostname);
+
/* N.B. caller will free nfs_server.hostname in all cases */
ctx->nfs_server.hostname = kmemdup_nul(dev_name, len, GFP_KERNEL);
if (!ctx->nfs_server.hostname)
--
2.24.1
