[PATCH] pcmcia: Add error handling for add_interval() in do_validate_mem()

[Wentao Liang]

In the do_validate_mem(), the call to add_interval() does not
handle errors. If kmalloc() fails in add_interval(), it could
result in a null pointer being inserted into the linked list,
leading to illegal memory access when sub_interval() is called
next.

This patch adds an error handling for the add_interval(). If
add_interval() returns an error, the function will return early
with the error code.

Fixes: 7b4884ca8853 ("pcmcia: validate late-added resources")
Signed-off-by: Wentao Liang <vulab@xxxxxxxxxxx>
---
 drivers/pcmcia/rsrc_nonstatic.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/pcmcia/rsrc_nonstatic.c b/drivers/pcmcia/rsrc_nonstatic.c
index bf9d070a4496..da494fe451ba 100644
--- a/drivers/pcmcia/rsrc_nonstatic.c
+++ b/drivers/pcmcia/rsrc_nonstatic.c
@@ -375,7 +375,9 @@ static int do_validate_mem(struct pcmcia_socket *s,
 
 	if (validate && !s->fake_cis) {
 		/* move it to the validated data set */
-		add_interval(&s_data->mem_db_valid, base, size);
+		ret = add_interval(&s_data->mem_db_valid, base, size);
+		if (ret)
+			return ret;
 		sub_interval(&s_data->mem_db, base, size);
 	}
 
-- 
2.42.0.windows.2