135 lines
3.3 KiB
C
135 lines
3.3 KiB
C
#include <linux/version.h>
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#include <linux/fs.h>
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#include <linux/nsproxy.h>
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#include <linux/filter.h>
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#include <linux/seccomp.h>
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#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 10, 0)
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#include <linux/sched/task.h>
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#else
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#include <linux/sched.h>
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#endif
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#include <linux/uaccess.h>
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#include "klog.h" // IWYU pragma: keep
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#include "kernel_compat.h"
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#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 10, 0) || \
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defined(CONFIG_IS_HW_HISI) || \
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defined(CONFIG_KSU_ALLOWLIST_WORKAROUND)
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#include <linux/key.h>
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#include <linux/errno.h>
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#include <linux/cred.h>
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struct key *init_session_keyring = NULL;
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static inline int install_session_keyring(struct key *keyring)
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{
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struct cred *new;
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int ret;
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new = prepare_creds();
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if (!new)
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return -ENOMEM;
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ret = install_session_keyring_to_cred(new, keyring);
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if (ret < 0) {
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abort_creds(new);
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return ret;
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}
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return commit_creds(new);
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}
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#endif
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#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 8, 0) || defined(KSU_OPTIONAL_STRNCPY)
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long ksu_strncpy_from_user_nofault(char *dst, const void __user *unsafe_addr,
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long count)
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{
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return strncpy_from_user_nofault(dst, unsafe_addr, count);
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}
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#elif LINUX_VERSION_CODE >= KERNEL_VERSION(5, 3, 0)
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long ksu_strncpy_from_user_nofault(char *dst, const void __user *unsafe_addr,
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long count)
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{
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return strncpy_from_unsafe_user(dst, unsafe_addr, count);
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}
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#else
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// Copied from: https://elixir.bootlin.com/linux/v4.9.337/source/mm/maccess.c#L201
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long ksu_strncpy_from_user_nofault(char *dst, const void __user *unsafe_addr,
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long count)
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{
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mm_segment_t old_fs = get_fs();
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long ret;
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if (unlikely(count <= 0))
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return 0;
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set_fs(USER_DS);
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pagefault_disable();
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ret = strncpy_from_user(dst, unsafe_addr, count);
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pagefault_enable();
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set_fs(old_fs);
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if (ret >= count) {
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ret = count;
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dst[ret - 1] = '\0';
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} else if (ret > 0) {
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ret++;
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}
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return ret;
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}
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#endif
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long ksu_strncpy_from_user_retry(char *dst, const void __user *unsafe_addr,
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long count)
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{
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long ret;
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ret = ksu_strncpy_from_user_nofault(dst, unsafe_addr, count);
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if (likely(ret >= 0))
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return ret;
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// we faulted! fallback to slow path
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if (unlikely(!ksu_access_ok(unsafe_addr, count))) {
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#ifdef CONFIG_KSU_DEBUG
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pr_err("%s: faulted!\n", __func__);
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#endif
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return -EFAULT;
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}
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// why we don't do like how strncpy_from_user_nofault?
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ret = strncpy_from_user(dst, unsafe_addr, count);
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if (ret >= count) {
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ret = count;
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dst[ret - 1] = '\0';
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} else if (likely(ret >= 0)) {
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ret++;
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}
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return ret;
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}
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long ksu_copy_from_user_nofault(void *dst, const void __user *src, size_t size)
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{
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#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 8, 0)
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return copy_from_user_nofault(dst, src, size);
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#else
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// https://elixir.bootlin.com/linux/v5.8/source/mm/maccess.c#L205
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long ret = -EFAULT;
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mm_segment_t old_fs = get_fs();
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set_fs(USER_DS);
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// tweaked to use ksu_access_ok
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if (ksu_access_ok(src, size)) {
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pagefault_disable();
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ret = __copy_from_user_inatomic(dst, src, size);
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pagefault_enable();
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}
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set_fs(old_fs);
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if (ret)
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return -EFAULT;
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return 0;
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#endif
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}
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