From: Hawkins Jiawei Date: Sun, 23 Oct 2022 16:39:45 +0000 (+0800) Subject: nfs: fix possible null-ptr-deref when parsing param X-Git-Tag: v6.1.8~934 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=55513864b418c6453d68aebc36cffcf965342426;p=platform%2Fkernel%2Flinux-starfive.git 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 Reviewed-by: Jeff Layton Signed-off-by: Trond Myklebust Signed-off-by: Sasha Levin --- diff --git a/fs/nfs/fs_context.c b/fs/nfs/fs_context.c index 09833ec..9bcd53d 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)) {