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authorXiaotian Feng <dfeng@redhat.com>2011-03-03 18:08:24 +0800
committerGreg Kroah-Hartman <gregkh@suse.de>2011-03-07 12:04:50 -0800
commit00bff392c81e4fb1901e5160fdd5afdb2546a6ab (patch)
treed07922748b7ed4d2053ebc0e0b7dc1df1f73230f /drivers/tty
parentb71dc8873427bb5bf0ce31b968c3f219a1d6d014 (diff)
downloadlinux-00bff392c81e4fb1901e5160fdd5afdb2546a6ab.tar.bz2
tty_audit: fix tty_audit_add_data live lock on audit disabled
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>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/tty_audit.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/tty/tty_audit.c b/drivers/tty/tty_audit.c
index f64582b0f623..7c5866920622 100644
--- a/drivers/tty/tty_audit.c
+++ b/drivers/tty/tty_audit.c
@@ -95,8 +95,10 @@ 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;