On Thursday, September 28, 2023 11:53:26 AM EDT Steve Grubb wrote: > On Thursday, September 21, 2023 4:02:49 PM EDT Amjad Gabbar wrote: > > > The best solution would be a kernel modification so that there are no > > > mismatched lists. > > > > I agree as well....This would be the cleanest solution. This would also > > solve the userspace problem of maintaining different lists which can get > > out of hand fairly quickly. > > After looking into this, a kernel patch would also not work well. It has to > be arch specific > > > > I guess we can warn on that to rewrite in syscall notation. > > > > We certainly should. I think the user should know that there is a > > performance cost associated with watches and we should explicitly mention > > how it can be optimized in the manpages also. The reason being I am > > pretty sure, numerous users/repos still do make use of the -w notation > > and we do want to let them know the issue here. We also need to make > > quite a few changes to the manpages also regarding this. Because, > > initially even I was very confused when reading the man pages and seeing > > the actual implementation of and results were not quite in sync. > > I have made the changes to the master and audit-3.1-maint branches. Please > everyone concerned give them tests. The short of it is that if you use the > '- w' notation for watches, it will remain the same and slower.
Actually, ths is the one that draws the warning to urge people to migrate. > If you use > the syscall notation without "-F arch", you will get a warning that it > cannot be optimized without adding "-Farch". Actually, you won't in order to preserve intentional behavior. > If you add "-F arch", you > will possibly need one for both arches which means doubling the rules. If > you do not want to double the rules, you might place a syscall rule for > any 32 system call (21-no32bit.rules). Or you can leave it as is and not > care. The sample rules and all man pages have been updated. I should have provided an example of what this means. If you have this kind of rule: -w /etc/shadow -p wa -k shadow And when applied draws a warning: # auditctl -w /etc/shadow -p wa -k shadow Old style watch rules are slower It should be rewritten as -a always,exit -F arch=b64 -F path=/etc/shadow -F perm=wa -F key=shadow Then it looks like this when loaded: #auditctl -l -a always,exit -F arch=b64 -S open,bind,truncate,ftruncate,rename,mkdir,rmdir,creat,link,unlink,symlink,chmod,fchmod,chown,fchown,lchown,mknod,acct,swapon,quotactl,setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr,openat,mkdirat,mknodat,fchownat,unlinkat,renameat,linkat,symlinkat,fchmodat,fallocate,renameat2,openat2 -F path=/etc/shadow -F perm=wa -F key=shadow And to delete the rule, auditctl -d always,exit -F arch=b64 -F path=/etc/shadow -F perm=wa -F key=shadow or the long way auditctl -d always,exit -F arch=b64 -S open,bind,truncate,ftruncate,rename,mkdir,rmdir,creat,link,unlink,symlink,chmod,fchmod,chown,fchown,lchown,mknod,acct,swapon,quotactl,setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr,openat,mkdirat,mknodat,fchownat,unlinkat,renameat,linkat,symlinkat,fchmodat,fallocate,renameat2,openat2 -F path=/etc/shadow -F perm=wa -F key=shadow Hopefully this is clearer what the change is. -Steve -- Linux-audit mailing list Linux-audit@redhat.com https://listman.redhat.com/mailman/listinfo/linux-audit
