projects/linux·commit f2c0d026

cap_syslog: don't use WARN_ONCE for CAP_SYS_ADMIN deprecation warning

f2c0d026 · Jonathan Nieder <[email protected]> · 2011-08-08 06:22:43 +02:00

syslog-ng versions before 3.3.0beta1 (2011-05-12) assume that
CAP_SYS_ADMIN is sufficient to access syslog, so ever since CAP_SYSLOG
was introduced (2010-11-25) they have triggered a warning.

Commit ee24aebffb75 ("cap_syslog: accept CAP_SYS_ADMIN for now")
improved matters a little by making syslog-ng work again, just keeping
the WARN_ONCE().  But still, this is a warning that writes a stack trace
we don't care about to syslog, sets a taint flag, and alarms sysadmins
when nothing worse has happened than use of an old userspace with a
recent kernel.

Convert the WARN_ONCE to a printk_once to avoid that while continuing to
give userspace developers a hint that this is an unwanted
backward-compatibility feature and won't be around forever.

Reported-by: Ralf Hildebrandt <[email protected]>
Reported-by: Niels <[email protected]>
Reported-by: Paweł Sikora <[email protected]>
Signed-off-by: Jonathan Nieder <[email protected]>
Liked-by: Gergely Nagy <[email protected]>
Acked-by: Serge Hallyn <[email protected]>
Acked-by: James Morris <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Commit
f2c0d0266cc5eb36a4aa44944b4096ec121490aa
Parents
9f50fad6

Changes

1 files changed · +4 −2

FileStatusAddDelContent
kernel/printk.cmodified+4−2View file

kernel/printk.c

View file
diff --git a/kernel/printk.c b/kernel/printk.c
index 37dff34..836a2ae 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -318,8 +318,10 @@ static int check_syslog_permissions(int type, bool from_file)
return 0;
/* For historical reasons, accept CAP_SYS_ADMIN too, with a warning */
if (capable(CAP_SYS_ADMIN)) {
- WARN_ONCE(1, "Attempt to access syslog with CAP_SYS_ADMIN "
- "but no CAP_SYSLOG (deprecated).\n");
+ printk_once(KERN_WARNING "%s (%d): "
+ "Attempt to access syslog with CAP_SYS_ADMIN "
+ "but no CAP_SYSLOG (deprecated).\n",
+ current->comm, task_pid_nr(current));
return 0;
}
return -EPERM;