linux/kernel/auditfilter.c, branch v2.6.28

Fix inotify watch removal/umount races

2008-11-15T20:26:44Z

Inotify watch removals suck violently. To kick the watch out we need (in this order) inode->inotify_mutex and ih->mutex. That's fine if we have a hold on inode; however, for all other cases we need to make damn sure we don't race with umount. We can *NOT* just grab a reference to a watch - inotify_unmount_inodes() will happily sail past it and we'll end with reference to inode potentially outliving its superblock. Ideally we just want to grab an active reference to superblock if we can; that will make sure we won't go into inotify_umount_inodes() until we are done. Cleanup is just deactivate_super(). However, that leaves a messy case - what if we *are* racing with umount() and active references to superblock can't be acquired anymore? We can bump ->s_count, grab ->s_umount, which will almost certainly wait until the superblock is shut down and the watch in question is pining for fjords. That's fine, but there is a problem - we might have hit the window between ->s_active getting to 0 / ->s_count - below S_BIAS (i.e. the moment when superblock is past the point of no return and is heading for shutdown) and the moment when deactivate_super() acquires ->s_umount. We could just do drop_super() yield() and retry, but that's rather antisocial and this stuff is luser-triggerable. OTOH, having grabbed ->s_umount and having found that we'd got there first (i.e. that ->s_root is non-NULL) we know that we won't race with inotify_umount_inodes(). So we could grab a reference to watch and do the rest as above, just with drop_super() instead of deactivate_super(), right? Wrong. We had to drop ih->mutex before we could grab ->s_umount. So the watch could've been gone already. That still can be dealt with - we need to save watch->wd, do idr_find() and compare its result with our pointer. If they match, we either have the damn thing still alive or we'd lost not one but two races at once, the watch had been killed and a new one got created with the same ->wd at the same address. That couldn't have happened in inotify_destroy(), but inotify_rm_wd() could run into that. Still, "new one got created" is not a problem - we have every right to kill it or leave it alone, whatever's more convenient. So we can use idr_find(...) == watch && watch->inode->i_sb == sb as "grab it and kill it" check. If it's been our original watch, we are fine, if it's a newcomer - nevermind, just pretend that we'd won the race and kill the fscker anyway; we are safe since we know that its superblock won't be going away. And yes, this is far beyond mere "not very pretty"; so's the entire concept of inotify to start with. Signed-off-by: Al Viro Acked-by: Greg KH Signed-off-by: Linus Torvalds

Re: [PATCH] the loginuid field should be output in all AUDIT_CONFIG_CHANGE audit messages

2008-08-01T16:15:03Z

> shouldn't these be using the "audit_get_loginuid(current)" and if we > are going to output loginuid we also should be outputting sessionid Thanks for your detailed explanation. I have made a new patch for outputing "loginuid" and "sessionid" by audit_get_loginuid(current) and audit_get_sessionid(current). If there are some deficiencies, please give me your indication. Signed-off-by: Zhang Xiliang Signed-off-by: Al Viro

[PATCH] remove useless argument type in audit_filter_user()

2008-06-25T03:36:35Z

The second argument "type" is not used in audit_filter_user(), so I think that type can be removed. If I'm wrong, please tell me. Signed-off-by: Peng Haitao Signed-off-by: Al Viro

[PATCH] audit: fix kernel-doc parameter notation

2008-06-25T03:36:28Z

Fix auditfilter kernel-doc misssing parameter description: Warning(lin2626-rc3//kernel/auditfilter.c:1551): No description found for parameter 'sessionid' Signed-off-by: Randy Dunlap Signed-off-by: Al Viro

Merge branch 'audit.b50' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current

2008-04-29T18:41:22Z

* 'audit.b50' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current: [PATCH] new predicate - AUDIT_FILETYPE [patch 2/2] Use find_task_by_vpid in audit code [patch 1/2] audit: let userspace fully control TTY input auditing [PATCH 2/2] audit: fix sparse shadowed variable warnings [PATCH 1/2] audit: move extern declarations to audit.h Audit: MAINTAINERS update Audit: increase the maximum length of the key field Audit: standardize string audit interfaces Audit: stop deadlock from signals under load Audit: save audit_backlog_limit audit messages in case auditd comes back Audit: collect sessionid in netlink messages Audit: end printk with newline

Remove duplicated unlikely() in IS_ERR()

2008-04-29T15:06:25Z

Some drivers have duplicated unlikely() macros. IS_ERR() already has unlikely() in itself. This patch cleans up such pointless code. Signed-off-by: Hirofumi Nakagawa Acked-by: David S. Miller Acked-by: Jeff Garzik Cc: Paul Clements Cc: Richard Purdie Cc: Alessandro Zummo Cc: David Brownell Cc: James Bottomley Cc: Michael Halcrow Cc: Anton Altaparmakov Cc: Al Viro Cc: Carsten Otte Cc: Patrick McHardy Cc: Paul Mundt Cc: Jaroslav Kysela Cc: Takashi Iwai Acked-by: Mike Frysinger Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] new predicate - AUDIT_FILETYPE

2008-04-28T10:28:37Z

Argument is S_IF... | , where index is normally 0 or 1. Triggers if chosen element of ctx->names[] is present and the mode of object in question matches the upper bits of argument. I.e. for things like "is the argument of that chmod a directory", etc. Signed-off-by: Al Viro

[PATCH 2/2] audit: fix sparse shadowed variable warnings

2008-04-28T10:28:17Z

Use msglen as the identifier. kernel/audit.c:724:10: warning: symbol 'len' shadows an earlier one kernel/audit.c:575:8: originally declared here Don't use ino_f to check the inode field at the end of the functions. kernel/auditfilter.c:429:22: warning: symbol 'f' shadows an earlier one kernel/auditfilter.c:420:21: originally declared here kernel/auditfilter.c:542:22: warning: symbol 'f' shadows an earlier one kernel/auditfilter.c:529:21: originally declared here i always used as a counter for a for loop and initialized to zero before use. Eliminate the inner i variables. kernel/auditsc.c:1295:8: warning: symbol 'i' shadows an earlier one kernel/auditsc.c:1152:6: originally declared here kernel/auditsc.c:1320:7: warning: symbol 'i' shadows an earlier one kernel/auditsc.c:1152:6: originally declared here Signed-off-by: Harvey Harrison Signed-off-by: Al Viro

[PATCH 1/2] audit: move extern declarations to audit.h

2008-04-28T10:28:04Z

Leave audit_sig_{uid|pid|sid} protected by #ifdef CONFIG_AUDITSYSCALL. Noticed by sparse: kernel/audit.c:73:6: warning: symbol 'audit_ever_enabled' was not declared. Should it be static? kernel/audit.c:100:8: warning: symbol 'audit_sig_uid' was not declared. Should it be static? kernel/audit.c:101:8: warning: symbol 'audit_sig_pid' was not declared. Should it be static? kernel/audit.c:102:6: warning: symbol 'audit_sig_sid' was not declared. Should it be static? kernel/audit.c:117:23: warning: symbol 'audit_ih' was not declared. Should it be static? kernel/auditfilter.c:78:18: warning: symbol 'audit_filter_list' was not declared. Should it be static? Signed-off-by: Harvey Harrison Signed-off-by: Al Viro

Audit: collect sessionid in netlink messages

2008-04-28T10:18:03Z

Previously I added sessionid output to all audit messages where it was available but we still didn't know the sessionid of the sender of netlink messages. This patch adds that information to netlink messages so we can audit who sent netlink messages. Signed-off-by: Eric Paris Signed-off-by: Al Viro