From: Eric W. Biederman ebiederm@xmission.com
commit c923a8e7edb010da67424077cbf1a6f1396ebd2e upstream.
During set*id() which cred->ucounts to charge the the current process to is not known until after set_cred_ucounts. So move the RLIMIT_NPROC checking into a new helper flag_nproc_exceeded and call flag_nproc_exceeded after set_cred_ucounts.
This is very much an arbitrary subset of the places where we currently change the RLIMIT_NPROC accounting, designed to preserve the existing logic.
Fixing the existing logic will be the subject of another series of changes.
Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20220216155832.680775-4-ebiederm@xmission.com Fixes: 21d1c5e386bc ("Reimplement RLIMIT_NPROC on top of ucounts") Signed-off-by: "Eric W. Biederman" ebiederm@xmission.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/sys.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-)
--- a/kernel/sys.c +++ b/kernel/sys.c @@ -472,6 +472,16 @@ static int set_user(struct cred *new) if (!new_user) return -EAGAIN;
+ free_uid(new->user); + new->user = new_user; + return 0; +} + +static void flag_nproc_exceeded(struct cred *new) +{ + if (new->ucounts == current_ucounts()) + return; + /* * We don't fail in case of NPROC limit excess here because too many * poorly written programs don't check set*uid() return code, assuming @@ -480,14 +490,10 @@ static int set_user(struct cred *new) * failure to the execve() stage. */ if (is_ucounts_overlimit(new->ucounts, UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC)) && - new_user != INIT_USER) + new->user != INIT_USER) current->flags |= PF_NPROC_EXCEEDED; else current->flags &= ~PF_NPROC_EXCEEDED; - - free_uid(new->user); - new->user = new_user; - return 0; }
/* @@ -562,6 +568,7 @@ long __sys_setreuid(uid_t ruid, uid_t eu if (retval < 0) goto error;
+ flag_nproc_exceeded(new); return commit_creds(new);
error: @@ -624,6 +631,7 @@ long __sys_setuid(uid_t uid) if (retval < 0) goto error;
+ flag_nproc_exceeded(new); return commit_creds(new);
error: @@ -703,6 +711,7 @@ long __sys_setresuid(uid_t ruid, uid_t e if (retval < 0) goto error;
+ flag_nproc_exceeded(new); return commit_creds(new);
error: