From d8e180dcd5bbbab9cd3ff2e779efcf70692ef541 Mon Sep 17 00:00:00 2001 From: Michal Schmidt Date: Thu, 20 Aug 2009 14:39:52 -0700 Subject: [PATCH] bsdacct: switch credentials for writing to the accounting file When process accounting is enabled, every exiting process writes a log to the account file. In addition, every once in a while one of the exiting processes checks whether there's enough free space for the log. SELinux policy may or may not allow the exiting process to stat the fs. So unsuspecting processes start generating AVC denials just because someone enabled process accounting. For these filesystem operations, the exiting process's credentials should be temporarily switched to that of the process which enabled accounting, because it's really that process which wanted to have the accounting information logged. Signed-off-by: Michal Schmidt Acked-by: David Howells Acked-by: Serge Hallyn Signed-off-by: Andrew Morton Signed-off-by: James Morris --- kernel/acct.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/kernel/acct.c b/kernel/acct.c index 9f3391090b3..9a4715a2f6b 100644 --- a/kernel/acct.c +++ b/kernel/acct.c @@ -491,13 +491,17 @@ static void do_acct_process(struct bsd_acct_struct *acct, u64 run_time; struct timespec uptime; struct tty_struct *tty; + const struct cred *orig_cred; + + /* Perform file operations on behalf of whoever enabled accounting */ + orig_cred = override_creds(file->f_cred); /* * First check to see if there is enough free_space to continue * the process accounting system. */ if (!check_free_space(acct, file)) - return; + goto out; /* * Fill the accounting struct with the needed info as recorded @@ -578,6 +582,8 @@ static void do_acct_process(struct bsd_acct_struct *acct, sizeof(acct_t), &file->f_pos); current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim; set_fs(fs); +out: + revert_creds(orig_cred); } /**