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authorAlexey Gladkov <legion@kernel.org>2021-04-22 14:27:09 +0200
committerEric W. Biederman <ebiederm@xmission.com>2021-04-30 14:14:00 -0500
commit905ae01c4ae2ae3df05bb141801b1db4b7d83c61 (patch)
treec4216c817bd6859c8028a25900bcfe4330c1e3c9 /kernel/user_namespace.c
parentf9c82a4ea89c384d49ce03768ba88d049ed3f1f0 (diff)
Add a reference to ucounts for each cred
For RLIMIT_NPROC and some other rlimits the user_struct that holds the global limit is kept alive for the lifetime of a process by keeping it in struct cred. Adding a pointer to ucounts in the struct cred will allow to track RLIMIT_NPROC not only for user in the system, but for user in the user_namespace. Updating ucounts may require memory allocation which may fail. So, we cannot change cred.ucounts in the commit_creds() because this function cannot fail and it should always return 0. For this reason, we modify cred.ucounts before calling the commit_creds(). Changelog v6: * Fix null-ptr-deref in is_ucounts_overlimit() detected by trinity. This error was caused by the fact that cred_alloc_blank() left the ucounts pointer empty. Reported-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Alexey Gladkov <legion@kernel.org> Link: https://lkml.kernel.org/r/b37aaef28d8b9b0d757e07ba6dd27281bbe39259.1619094428.git.legion@kernel.org Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Diffstat (limited to 'kernel/user_namespace.c')
-rw-r--r--kernel/user_namespace.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 9a4b980d695b..f1b7b4b8ffa2 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -1340,6 +1340,9 @@ static int userns_install(struct nsset *nsset, struct ns_common *ns)
put_user_ns(cred->user_ns);
set_cred_user_ns(cred, get_user_ns(user_ns));
+ if (set_cred_ucounts(cred) < 0)
+ return -EINVAL;
+
return 0;
}