D7net
Home
Console
Upload
information
Create File
Create Folder
About
Tools
:
/
usr
/
src
/
file_protector-1.1-1592
/
Filename :
compat.c
back
Copy
/** @file @brief Support for legacy Linux kernel versions @details Copyright (c) 2018-2021 Acronis International GmbH @author Mikhail Krivtsov (mikhail.krivtsov@acronis.com) @since $Id: $ */ #include "compat.h" #include "debug.h" #include <linux/magic.h> /* * 'get_task_exe_file()' appeared in 'stable/v4.8', * it was backported in RedHat/CentOS 7 (kernel v3.10) */ #ifndef HAVE_GET_TASK_EXE #ifndef KERNEL_MOCK #include <linux/sched.h> // task_lock() #else #include <mock/mock_sched.h> #endif // 'get_mm_exe_file' is not 'exported' static struct file *get_mm_exe_file_impl(struct mm_struct *mm) { struct file *exe_file; /* * We need mmap_sem to protect against races with removal of * VM_EXECUTABLE vmas */ down_read(&mm->mmap_sem); exe_file = mm->exe_file; if (exe_file) get_file(exe_file); up_read(&mm->mmap_sem); return exe_file; } struct file *get_task_exe_file_impl(struct task_struct *task) { struct file *exe_file = NULL; struct mm_struct *mm; mm = get_task_mm(task); if (mm) { exe_file = get_mm_exe_file_impl(mm); mmput(mm); } return exe_file; } #elif defined(GET_TASK_EXE_NOT_EXPORTED) #ifndef HAVE_GET_FILE_RCU_DOUBLE_POINTER //copy from 5.15 static struct file *get_mm_exe_file_impl(struct mm_struct *mm) { struct file *exe_file; rcu_read_lock(); exe_file = rcu_dereference(mm->exe_file); if (exe_file && !get_file_rcu(exe_file)) exe_file = NULL; rcu_read_unlock(); return exe_file; } #else //copy from 6.7 static struct file *get_mm_exe_file_impl(struct mm_struct *mm) { struct file *exe_file; rcu_read_lock(); exe_file = get_file_rcu(&mm->exe_file); rcu_read_unlock(); return exe_file; } #endif struct file *get_task_exe_file_impl(struct task_struct *task) { struct file *exe_file = NULL; struct mm_struct *mm; task_lock(task); mm = task->mm; if (mm) { if (!(task->flags & PF_KTHREAD)) exe_file = get_mm_exe_file_impl(mm); } task_unlock(task); return exe_file; } #endif #ifndef HAVE_KALLSYMS_LOOKUP_NAME // { #include <linux/kallsyms.h> // kallsyms_on_each_symbol() typedef struct { const char *name; unsigned long kallsyms_address; } kallsyms_lookup_name_ctx_t; #if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 7, 0) #include <linux/kprobes.h> static unsigned long kprobe_find_symbol(const char *symbol_name) { void *symbol_ptr = 0; char symbol_name_buffer[NAME_MAX] = {0}; struct kprobe kp = { .symbol_name = symbol_name, .addr = 0, }; IPRINTF("searching for [%s] by kprobe", symbol_name); register_kprobe(&kp); symbol_ptr = (void *)kp.addr; unregister_kprobe(&kp); IPRINTF("%s: [0x%p] [%pS]", symbol_name, symbol_ptr, symbol_ptr); snprintf(symbol_name_buffer, NAME_MAX, "%ps", symbol_ptr); if (strncmp(symbol_name_buffer, symbol_name, strlen(symbol_name)) != 0) { EPRINTF("%s address [%p] is wrong", symbol_name, (void *)symbol_ptr); return 0; } return (unsigned long)symbol_ptr; } #else static int kallsyms_lookup_name_on_each_symbol_cb(void *data, const char *namebuf, struct module *module, unsigned long kallsyms_address) { kallsyms_lookup_name_ctx_t *ctx = data; (void) module; if (0 == strcmp(namebuf, ctx->name)) { ctx->kallsyms_address = kallsyms_address; return 1; } return 0; } #endif unsigned long compat_kallsyms_lookup_name(const char *name) { #if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 7, 0) return kprobe_find_symbol(name); #else kallsyms_lookup_name_ctx_t ctx = { .name = name, .kallsyms_address = 0, }; if (kallsyms_on_each_symbol(kallsyms_lookup_name_on_each_symbol_cb, &ctx)) { DPRINTF("name='%s' address=0x%lx", name, ctx.kallsyms_address); return ctx.kallsyms_address; } else { DPRINTF("name='%s' not found", name); return 0; } return 0; #endif } // } #endif // tracepoint registration interface was modified in 'stable/v3.15' #ifdef HAVE_TRACEPOINT_PROBE_REGISTER_STRUCT // { #include <linux/tracepoint.h> // for_each_kernel_tracepoint(), // tracepoint_probe_register(), // tracepoint_probe_unregister() typedef struct { const char *name; struct tracepoint *tracepoint; } lookup_tracepoint_ctx_t; static void lookup_tracepoint_on_each_tracepoint_cb(struct tracepoint *tp, void *data) { lookup_tracepoint_ctx_t *ctx = data; //DPRINTF("%p %s", tp, tp->name); if (0 == strcmp(tp->name, ctx->name)) { ctx->tracepoint = tp; } } static struct tracepoint *lookup_tracepoint(const char *name) { lookup_tracepoint_ctx_t ctx = { .name = name, .tracepoint = 0, }; for_each_kernel_tracepoint(lookup_tracepoint_on_each_tracepoint_cb, &ctx); return ctx.tracepoint; } int tracepoint_probe_register_compat(const char *name, void *probe, void *data) { struct tracepoint *tp = lookup_tracepoint(name); return (!tp) ? -ENOSYS : tracepoint_probe_register(tp, probe, data); } int tracepoint_probe_unregister_compat(const char *name, void *probe, void *data) { struct tracepoint *tp = lookup_tracepoint(name); return (!tp) ? -ENOSYS : tracepoint_probe_unregister(tp, probe, data); } // } #endif // rbtree postorder iteration functions appeared in 'stable/v3.12' #if !defined(HAVE_RB_FIRST_POSTORDER) || !defined(HAVE_RB_NEXT_POSTORDER) static struct rb_node *rb_left_deepest_node(const struct rb_node *node) { for (;;) { if (node->rb_left) node = node->rb_left; else if (node->rb_right) node = node->rb_right; else return (struct rb_node *)node; } } #endif #ifndef HAVE_RB_NEXT_POSTORDER struct rb_node *rb_next_postorder(const struct rb_node *node) { const struct rb_node *parent; if (!node) return NULL; parent = rb_parent(node); /* If we're sitting on node, we've already seen our children */ if (parent && node == parent->rb_left && parent->rb_right) { /* If we are the parent's left node, go to the parent's right * node then all the way down to the left */ return rb_left_deepest_node(parent->rb_right); } else /* Otherwise we are the parent's right node, and the parent * should be next */ return (struct rb_node *)parent; } #endif #ifndef HAVE_RB_FIRST_POSTORDER struct rb_node *rb_first_postorder(const struct rb_root *root) { if (!root->rb_node) return NULL; return rb_left_deepest_node(root->rb_node); } #endif d_absolute_path_compat_fn g_d_absolute_path_compat = NULL; void compat_init(void) { g_d_absolute_path_compat = (d_absolute_path_compat_fn) compat_kallsyms_lookup_name("d_absolute_path"); } #ifdef STATX_BTIME // Filter by magics that can support btime and can get it quickly // Local fses that support btime #ifndef BTRFS_SUPER_MAGIC #define BTRFS_SUPER_MAGIC 0x9123683E #endif #ifndef EXFAT_SUPER_MAGIC #define EXFAT_SUPER_MAGIC 0x2011BAB0 #endif #ifndef EXT4_SUPER_MAGIC #define EXT4_SUPER_MAGIC 0xEF53 #endif #ifndef F2FS_SUPER_MAGIC #define F2FS_SUPER_MAGIC 0xF2F52010 #endif #ifndef MSDOS_SUPER_MAGIC #define MSDOS_SUPER_MAGIC 0x4d44 #endif #ifndef HFSPLUS_VOLHEAD_SIG #define HFSPLUS_VOLHEAD_SIG 0x482B #endif #ifndef XFS_SUPER_MAGIC #define XFS_SUPER_MAGIC 0x58465342 #endif // Network fses that support btime and can get it quickly by means of AT_STATX_DONT_SYNC #ifndef NFS_SUPER_MAGIC #define NFS_SUPER_MAGIC 0x6969 #endif #ifndef FUSE_SUPER_MAGIC #define FUSE_SUPER_MAGIC 0x65735546 #endif #ifndef CIFS_SUPER_MAGIC #define CIFS_SUPER_MAGIC 0xFF534D42 #endif static inline bool is_magic_allowed_for_fast_getattr(const struct inode* ino) { unsigned long magic = ino->i_sb->s_magic; if (magic == BTRFS_SUPER_MAGIC || magic == EXFAT_SUPER_MAGIC || magic == EXT4_SUPER_MAGIC || magic == F2FS_SUPER_MAGIC || magic == MSDOS_SUPER_MAGIC || magic == HFSPLUS_VOLHEAD_SIG || magic == XFS_SUPER_MAGIC) return true; #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 16, 0) if (magic == NFS_SUPER_MAGIC) return true; #endif #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 18, 0) if (magic == FUSE_SUPER_MAGIC) return true; #endif #if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 7, 0) if (magic == CIFS_SUPER_MAGIC) return true; #endif return false; } int vfs_getattr_basic_fast(const struct path *path, struct kstat *stat) { if (!is_magic_allowed_for_fast_getattr(path->dentry->d_inode)) return -EINVAL; return vfs_getattr_nosec(path, stat, STATX_TYPE | STATX_MODE | STATX_UID | STATX_GID | STATX_ATIME | STATX_MTIME | STATX_CTIME | STATX_SIZE | STATX_BTIME | STATX_INO, AT_STATX_DONT_SYNC); } #endif