| Message ID | 20221023163945.39920-3-yin31149@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fs: fix possible null-ptr-deref when parsing param | expand |
On Mon, 2022-10-24 at 00:39 +0800, Hawkins Jiawei wrote: > 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> > --- > fs/nfs/fs_context.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/fs/nfs/fs_context.c b/fs/nfs/fs_context.c > index 4da701fd1424..0c330bc13ef2 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)) { Looks reasonable. I took a quick look for other fsparam_string values that might not handle a NULL pointer correctly, but I didn't see any. Reviewed-by: Jeff Layton <jlayton@kernel.org>
diff --git a/fs/nfs/fs_context.c b/fs/nfs/fs_context.c index 4da701fd1424..0c330bc13ef2 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)) {
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> --- fs/nfs/fs_context.c | 6 ++++++ 1 file changed, 6 insertions(+)