[PATCH] tpm: Fix auth session leak in tpm2_get_random() error path

[Jiangshan Yi]

When tpm_buf_fill_hmac_session() fails in tpm2_get_random(), the error
path returns without calling tpm2_end_auth_session(), leaking the auth
session. All other error paths in the function handle this correctly.

Fixes: 3d9e043dab0a ("tpm-buf: Memory-safe allocations")
Cc: sta...@vger.kernel.org
Signed-off-by: Jiangshan Yi <yijiangs...@kylinos.cn>
---
 drivers/char/tpm/tpm2-cmd.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 48cec39995fe..96e0e06bbbf0 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -281,8 +281,10 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, 
size_t max)
                }
                tpm_buf_append_u16(buf, num_bytes);
                err = tpm_buf_fill_hmac_session(chip, buf);
-               if (err)
+               if (err) {
+                       tpm2_end_auth_session(chip);
                        return err;
+               }
 
                err = tpm_transmit_cmd(chip, buf,
                                       offsetof(struct tpm2_get_random_out,
-- 
2.25.1