diff options
author | Xiaotian Feng <dfeng@redhat.com> | 2011-03-03 18:08:24 +0800 |
---|---|---|
committer | Willy Tarreau <w@1wt.eu> | 2012-10-07 23:37:14 +0200 |
commit | a82ca695591da11eb8cb74d4cb57e8f476297932 (patch) | |
tree | 66d5dd4654411473d7adb662be6c2ac199cd7b6a /drivers/char | |
parent | 2f42878e56a734563c5e2aadee6e334477500cdf (diff) |
tty_audit: fix tty_audit_add_data live lock on audit disabled
commit 00bff392c81e4fb1901e5160fdd5afdb2546a6ab upstream.
The current tty_audit_add_data code:
do {
size_t run;
run = N_TTY_BUF_SIZE - buf->valid;
if (run > size)
run = size;
memcpy(buf->data + buf->valid, data, run);
buf->valid += run;
data += run;
size -= run;
if (buf->valid == N_TTY_BUF_SIZE)
tty_audit_buf_push_current(buf);
} while (size != 0);
If the current buffer is full, kernel will then call tty_audit_buf_push_current
to empty the buffer. But if we disabled audit at the same time, tty_audit_buf_push()
returns immediately if audit_enabled is zero. Without emptying the buffer.
With obvious effect on tty_audit_add_data() that ends up spinning in that loop,
copying 0 bytes at each iteration and attempting to push each time without any effect.
Holding the lock all along.
Suggested-by: Alexander Viro <aviro@redhat.com>
Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Diffstat (limited to 'drivers/char')
-rw-r--r-- | drivers/char/tty_audit.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/char/tty_audit.c b/drivers/char/tty_audit.c index ac16fbec72d0..dd4691a7631b 100644 --- a/drivers/char/tty_audit.c +++ b/drivers/char/tty_audit.c @@ -94,8 +94,10 @@ static void tty_audit_buf_push(struct task_struct *tsk, uid_t loginuid, { if (buf->valid == 0) return; - if (audit_enabled == 0) + if (audit_enabled == 0) { + buf->valid = 0; return; + } tty_audit_log("tty", tsk, loginuid, sessionid, buf->major, buf->minor, buf->data, buf->valid); buf->valid = 0; |