[PATCH next] tpm: Fix a possible dereference of ERR_PTR in tpm_init()

Harshit Mogalapalli
2023-03-21T06:14:36Z

Smatch reports:
drivers/char/tpm/tpm-interface.c:470 tpm_init() error:
'tpm_class' dereferencing possible ERR_PTR()

If class_create() returns error pointer, we are dereferencing a possible
error pointer. Fix this by moving the dereference post error handling.

Fixes: a010eb881243 ("tpm: fix up the tpm_class shutdown_pre pointer when created")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
---
This is based on static analysis, only compile tested.
---
drivers/char/tpm/tpm-interface.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 43e23a04433a..4463d0018290 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -467,12 +467,13 @@ static int __init tpm_init(void)
int rc;

tpm_class = class_create("tpm");
- tpm_class->shutdown_pre = tpm_class_shutdown;
if (IS_ERR(tpm_class)) {
pr_err("couldn't create tpm class\n");
return PTR_ERR(tpm_class);
}

+ tpm_class->shutdown_pre = tpm_class_shutdown;
+
tpmrm_class = class_create("tpmrm");
if (IS_ERR(tpmrm_class)) {
pr_err("couldn't create tpmrm class\n");
--
2.38.1