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authorAlexey Gladkov <legion@kernel.org>2021-04-22 15:27:16 +0300
committerEric W. Biederman <ebiederm@xmission.com>2021-04-30 22:14:03 +0300
commitc1ada3dc7219b02b3467aa906c2f5f8b098578d1 (patch)
treeed42c25748ccbec5d4704b99d4934f1b6c91ffe8 /include/linux/user_namespace.h
parente4aebf06695c32d49f1007f9d252f97b5b2998a7 (diff)
downloadlinux-c1ada3dc7219b02b3467aa906c2f5f8b098578d1.tar.xz
ucounts: Set ucount_max to the largest positive value the type can hold
The ns->ucount_max[] is signed long which is less than the rlimit size. We have to protect ucount_max[] from overflow and only use the largest value that we can hold. On 32bit using "long" instead of "unsigned long" to hold the counts has the downside that RLIMIT_MSGQUEUE and RLIMIT_MEMLOCK are limited to 2GiB instead of 4GiB. I don't think anyone cares but it should be mentioned in case someone does. The RLIMIT_NPROC and RLIMIT_SIGPENDING used atomic_t so their maximum hasn't changed. Signed-off-by: Alexey Gladkov <legion@kernel.org> Link: https://lkml.kernel.org/r/1825a5dfa18bc5a570e79feb05e2bd07fd57e7e3.1619094428.git.legion@kernel.org Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Diffstat (limited to 'include/linux/user_namespace.h')
-rw-r--r--include/linux/user_namespace.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 2a3177b9b8bf..61794ae32fa8 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -125,6 +125,12 @@ long inc_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v);
bool dec_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v);
bool is_ucounts_overlimit(struct ucounts *ucounts, enum ucount_type type, unsigned long max);
+static inline void set_rlimit_ucount_max(struct user_namespace *ns,
+ enum ucount_type type, unsigned long max)
+{
+ ns->ucount_max[type] = max <= LONG_MAX ? max : LONG_MAX;
+}
+
#ifdef CONFIG_USER_NS
static inline struct user_namespace *get_user_ns(struct user_namespace *ns)