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| author |   Alexey Gladkov <legion@kernel.org> | 2021-04-22 14:27:16 +0200 |
|---|---|---|
| committer |   Eric W. Biederman <ebiederm@xmission.com> | 2021-04-30 14:14:03 -0500 |
| commit | c1ada3dc7219b02b3467aa906c2f5f8b098578d1 (patch) | |
| tree | ed42c25748ccbec5d4704b99d4934f1b6c91ffe8 /kernel/fork.c | |
| parent | kselftests: Add test to check for rlimit changes in different user namespaces (diff) | |
| download | linux-dev-c1ada3dc7219b02b3467aa906c2f5f8b098578d1.tar.xz linux-dev-c1ada3dc7219b02b3467aa906c2f5f8b098578d1.zip | |
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 'kernel/fork.c')
| -rw-r--r-- | kernel/fork.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index 610fd4de60d7..c41820481b2e 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -822,10 +822,10 @@ void __init fork_init(void) for (i = 0; i < MAX_PER_NAMESPACE_UCOUNTS; i++) init_user_ns.ucount_max[i] = max_threads/2; - init_user_ns.ucount_max[UCOUNT_RLIMIT_NPROC] = task_rlimit(&init_task, RLIMIT_NPROC); - init_user_ns.ucount_max[UCOUNT_RLIMIT_MSGQUEUE] = task_rlimit(&init_task, RLIMIT_MSGQUEUE); - init_user_ns.ucount_max[UCOUNT_RLIMIT_SIGPENDING] = task_rlimit(&init_task, RLIMIT_SIGPENDING); - init_user_ns.ucount_max[UCOUNT_RLIMIT_MEMLOCK] = task_rlimit(&init_task, RLIMIT_MEMLOCK); + set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_NPROC, task_rlimit(&init_task, RLIMIT_NPROC)); + set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_MSGQUEUE, task_rlimit(&init_task, RLIMIT_MSGQUEUE)); + set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_SIGPENDING, task_rlimit(&init_task, RLIMIT_SIGPENDING)); + set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_MEMLOCK, task_rlimit(&init_task, RLIMIT_MEMLOCK)); #ifdef CONFIG_VMAP_STACK cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache", |