diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cgroup/cgroup.c | 33 | ||||
| -rw-r--r-- | kernel/cred.c | 9 | ||||
| -rw-r--r-- | kernel/memremap.c | 23 | ||||
| -rw-r--r-- | kernel/ptrace.c | 20 |
4 files changed, 49 insertions, 36 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 155048b0eca2..426a0026225c 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -1460,8 +1460,8 @@ struct cgroup *task_cgroup_from_root(struct task_struct *task, static struct kernfs_syscall_ops cgroup_kf_syscall_ops; -static char *cgroup_fill_name(struct cgroup *cgrp, const struct cftype *cft, - char *buf, bool write_link_name) +static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft, + char *buf) { struct cgroup_subsys *ss = cft->ss; @@ -1471,26 +1471,13 @@ static char *cgroup_fill_name(struct cgroup *cgrp, const struct cftype *cft, snprintf(buf, CGROUP_FILE_NAME_MAX, "%s%s.%s", dbg, cgroup_on_dfl(cgrp) ? ss->name : ss->legacy_name, - write_link_name ? cft->link_name : cft->name); + cft->name); } else { - strscpy(buf, write_link_name ? cft->link_name : cft->name, - CGROUP_FILE_NAME_MAX); + strscpy(buf, cft->name, CGROUP_FILE_NAME_MAX); } return buf; } -static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft, - char *buf) -{ - return cgroup_fill_name(cgrp, cft, buf, false); -} - -static char *cgroup_link_name(struct cgroup *cgrp, const struct cftype *cft, - char *buf) -{ - return cgroup_fill_name(cgrp, cft, buf, true); -} - /** * cgroup_file_mode - deduce file mode of a control file * @cft: the control file in question @@ -1649,9 +1636,6 @@ static void cgroup_rm_file(struct cgroup *cgrp, const struct cftype *cft) } kernfs_remove_by_name(cgrp->kn, cgroup_file_name(cgrp, cft, name)); - if (cft->flags & CFTYPE_SYMLINKED) - kernfs_remove_by_name(cgrp->kn, - cgroup_link_name(cgrp, cft, name)); } /** @@ -3837,7 +3821,6 @@ static int cgroup_add_file(struct cgroup_subsys_state *css, struct cgroup *cgrp, { char name[CGROUP_FILE_NAME_MAX]; struct kernfs_node *kn; - struct kernfs_node *kn_link; struct lock_class_key *key = NULL; int ret; @@ -3868,14 +3851,6 @@ static int cgroup_add_file(struct cgroup_subsys_state *css, struct cgroup *cgrp, spin_unlock_irq(&cgroup_file_kn_lock); } - if (cft->flags & CFTYPE_SYMLINKED) { - kn_link = kernfs_create_link(cgrp->kn, - cgroup_link_name(cgrp, cft, name), - kn); - if (IS_ERR(kn_link)) - return PTR_ERR(kn_link); - } - return 0; } diff --git a/kernel/cred.c b/kernel/cred.c index e74ffdc98a92..c73a87a4df13 100644 --- a/kernel/cred.c +++ b/kernel/cred.c @@ -446,6 +446,15 @@ int commit_creds(struct cred *new) if (task->mm) set_dumpable(task->mm, suid_dumpable); task->pdeath_signal = 0; + /* + * If a task drops privileges and becomes nondumpable, + * the dumpability change must become visible before + * the credential change; otherwise, a __ptrace_may_access() + * racing with this change may be able to attach to a task it + * shouldn't be able to attach to (as if the task had dropped + * privileges without becoming nondumpable). + * Pairs with a read barrier in __ptrace_may_access(). + */ smp_wmb(); } diff --git a/kernel/memremap.c b/kernel/memremap.c index 1490e63f69a9..6e1970719dc2 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -95,6 +95,7 @@ static void devm_memremap_pages_release(void *data) pgmap->kill(pgmap->ref); for_each_device_pfn(pfn, pgmap) put_page(pfn_to_page(pfn)); + pgmap->cleanup(pgmap->ref); /* pages are dead and unused, undo the arch mapping */ align_start = res->start & ~(SECTION_SIZE - 1); @@ -133,8 +134,8 @@ static void devm_memremap_pages_release(void *data) * 2/ The altmap field may optionally be initialized, in which case altmap_valid * must be set to true * - * 3/ pgmap->ref must be 'live' on entry and will be killed at - * devm_memremap_pages_release() time, or if this routine fails. + * 3/ pgmap->ref must be 'live' on entry and will be killed and reaped + * at devm_memremap_pages_release() time, or if this routine fails. * * 4/ res is expected to be a host memory range that could feasibly be * treated as a "System RAM" range, i.e. not a device mmio range, but @@ -156,8 +157,10 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) pgprot_t pgprot = PAGE_KERNEL; int error, nid, is_ram; - if (!pgmap->ref || !pgmap->kill) + if (!pgmap->ref || !pgmap->kill || !pgmap->cleanup) { + WARN(1, "Missing reference count teardown definition\n"); return ERR_PTR(-EINVAL); + } align_start = res->start & ~(SECTION_SIZE - 1); align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE) @@ -168,14 +171,16 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) if (conflict_pgmap) { dev_WARN(dev, "Conflicting mapping in same section\n"); put_dev_pagemap(conflict_pgmap); - return ERR_PTR(-ENOMEM); + error = -ENOMEM; + goto err_array; } conflict_pgmap = get_dev_pagemap(PHYS_PFN(align_end), NULL); if (conflict_pgmap) { dev_WARN(dev, "Conflicting mapping in same section\n"); put_dev_pagemap(conflict_pgmap); - return ERR_PTR(-ENOMEM); + error = -ENOMEM; + goto err_array; } is_ram = region_intersects(align_start, align_size, @@ -267,10 +272,18 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) pgmap_array_delete(res); err_array: pgmap->kill(pgmap->ref); + pgmap->cleanup(pgmap->ref); + return ERR_PTR(error); } EXPORT_SYMBOL_GPL(devm_memremap_pages); +void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap) +{ + devm_release_action(dev, devm_memremap_pages_release, pgmap); +} +EXPORT_SYMBOL_GPL(devm_memunmap_pages); + unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) { /* number of pfns from base where pfn_to_page() is valid */ diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 5710d07e67cf..8456b6e2205f 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -324,6 +324,16 @@ static int __ptrace_may_access(struct task_struct *task, unsigned int mode) return -EPERM; ok: rcu_read_unlock(); + /* + * If a task drops privileges and becomes nondumpable (through a syscall + * like setresuid()) while we are trying to access it, we must ensure + * that the dumpability is read after the credentials; otherwise, + * we may be able to attach to a task that we shouldn't be able to + * attach to (as if the task had dropped privileges without becoming + * nondumpable). + * Pairs with a write barrier in commit_creds(). + */ + smp_rmb(); mm = task->mm; if (mm && ((get_dumpable(mm) != SUID_DUMP_USER) && @@ -705,6 +715,10 @@ static int ptrace_peek_siginfo(struct task_struct *child, if (arg.nr < 0) return -EINVAL; + /* Ensure arg.off fits in an unsigned long */ + if (arg.off > ULONG_MAX) + return 0; + if (arg.flags & PTRACE_PEEKSIGINFO_SHARED) pending = &child->signal->shared_pending; else @@ -712,18 +726,20 @@ static int ptrace_peek_siginfo(struct task_struct *child, for (i = 0; i < arg.nr; ) { kernel_siginfo_t info; - s32 off = arg.off + i; + unsigned long off = arg.off + i; + bool found = false; spin_lock_irq(&child->sighand->siglock); list_for_each_entry(q, &pending->list, list) { if (!off--) { + found = true; copy_siginfo(&info, &q->info); break; } } spin_unlock_irq(&child->sighand->siglock); - if (off >= 0) /* beyond the end of the list */ + if (!found) /* beyond the end of the list */ break; #ifdef CONFIG_COMPAT |
