From 25a2fb244c0859b088649d2c4b2b44ba562f25a8 Mon Sep 17 00:00:00 2001 From: Vasily Averin Date: Tue, 22 Sep 2020 10:20:04 +0800 Subject: [PATCH] tpm: tpm2_bios_measurements_next should increase position index stable inclusion from linux-4.19.116 commit 6415769223b072d59118ca3c63f0ca31a552a7e3 -------------------------------- commit f9bf8adb55cd5a357b247a16aafddf8c97b276e0 upstream. If .next function does not change position index, following .show function will repeat output related to current position index. For /sys/kernel/security/tpm0/binary_bios_measurements: 1) read after lseek beyound end of file generates whole last line. 2) read after lseek to middle of last line generates expected end of last line and unexpected whole last line once again. Cc: stable@vger.kernel.org # 4.19.x Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code ...") Link: https://bugzilla.kernel.org/show_bug.cgi?id=206283 Signed-off-by: Vasily Averin Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen Signed-off-by: Greg Kroah-Hartman Signed-off-by: Yang Yingliang --- drivers/char/tpm/eventlog/tpm2.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/char/tpm/eventlog/tpm2.c b/drivers/char/tpm/eventlog/tpm2.c index e27f2cebd808..820128167607 100644 --- a/drivers/char/tpm/eventlog/tpm2.c +++ b/drivers/char/tpm/eventlog/tpm2.c @@ -143,6 +143,7 @@ static void *tpm2_bios_measurements_next(struct seq_file *m, void *v, size_t event_size; void *marker; + (*pos)++; event_header = log->bios_event_log; if (v == SEQ_START_TOKEN) { @@ -167,7 +168,6 @@ static void *tpm2_bios_measurements_next(struct seq_file *m, void *v, if (((v + event_size) >= limit) || (event_size == 0)) return NULL; - (*pos)++; return v; } -- GitLab