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authorJonathan Nieder <jrnieder@gmail.com>2011-08-08 06:22:43 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2011-08-09 18:22:22 -0700
commitf2c0d0266cc5eb36a4aa44944b4096ec121490aa (patch)
tree1f3ec14316bf428e278c06059868c85c87df53cb /kernel/printk.c
parent9f50fad65b87a8776ae989ca059ad6c17925dfc3 (diff)
downloadlwn-f2c0d0266cc5eb36a4aa44944b4096ec121490aa.tar.gz
lwn-f2c0d0266cc5eb36a4aa44944b4096ec121490aa.zip
cap_syslog: don't use WARN_ONCE for CAP_SYS_ADMIN deprecation warning
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 <ralf.hildebrandt@charite.de> Reported-by: Niels <zorglub_olsen@hotmail.com> Reported-by: Paweł Sikora <pluto@agmk.net> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Liked-by: Gergely Nagy <algernon@madhouse-project.org> Acked-by: Serge Hallyn <serge@hallyn.com> Acked-by: James Morris <jmorris@namei.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/printk.c')
-rw-r--r--kernel/printk.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/printk.c b/kernel/printk.c
index 37dff3429adb..836a2ae0ac31 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;