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authorHawkins Jiawei <yin31149@gmail.com>2022-10-24 00:39:45 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2022-12-31 13:33:04 +0100
commit55513864b418c6453d68aebc36cffcf965342426 (patch)
tree5d9f1b1ea5dd4c38d26e26d5a6988bfa711c3076 /fs/nfs
parent96521aa5bc7658e9d674da4aa0260dea4396b9a6 (diff)
downloadlinux-55513864b418c6453d68aebc36cffcf965342426.tar.gz
nfs: fix possible null-ptr-deref when parsing param
[ Upstream commit 5559405df652008e56eee88872126fe4c451da67 ]

According to commit "vfs: parse: deal with zero length string value",
kernel will set the param->string to null pointer in vfs_parse_fs_string()
if fs string has zero length.

Yet the problem is that, nfs_fs_context_parse_param() will dereferences the
param->string, without checking whether it is a null pointer, which may
trigger a null-ptr-deref bug.

This patch solves it by adding sanity check on param->string
in nfs_fs_context_parse_param().

Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs/nfs')
-rw-r--r--fs/nfs/fs_context.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/nfs/fs_context.c b/fs/nfs/fs_context.c
index 09833ec102fc..9bcd53d5c7d4 100644
--- a/fs/nfs/fs_context.c
+++ b/fs/nfs/fs_context.c
@@ -684,6 +684,8 @@ static int nfs_fs_context_parse_param(struct fs_context *fc,
 			return ret;
 		break;
 	case Opt_vers:
+		if (!param->string)
+			goto out_invalid_value;
 		trace_nfs_mount_assign(param->key, param->string);
 		ret = nfs_parse_version_string(fc, param->string);
 		if (ret < 0)
@@ -696,6 +698,8 @@ static int nfs_fs_context_parse_param(struct fs_context *fc,
 		break;
 
 	case Opt_proto:
+		if (!param->string)
+			goto out_invalid_value;
 		trace_nfs_mount_assign(param->key, param->string);
 		protofamily = AF_INET;
 		switch (lookup_constant(nfs_xprt_protocol_tokens, param->string, -1)) {
@@ -732,6 +736,8 @@ static int nfs_fs_context_parse_param(struct fs_context *fc,
 		break;
 
 	case Opt_mountproto:
+		if (!param->string)
+			goto out_invalid_value;
 		trace_nfs_mount_assign(param->key, param->string);
 		mountfamily = AF_INET;
 		switch (lookup_constant(nfs_xprt_protocol_tokens, param->string, -1)) {