Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * security/tomoyo/realpath.c
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  * Copyright (C) 2005-2011  NTT DATA CORPORATION
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) #include "common.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) #include <linux/magic.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) #include <linux/proc_fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13)  * tomoyo_encode2 - Encode binary string to ascii string.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15)  * @str:     String in binary format.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16)  * @str_len: Size of @str in byte.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18)  * Returns pointer to @str in ascii format on success, NULL otherwise.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20)  * This function uses kzalloc(), so caller must kfree() if this function
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21)  * didn't return NULL.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) char *tomoyo_encode2(const char *str, int str_len)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) 	int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) 	int len = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) 	const char *p = str;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 	char *cp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) 	char *cp0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) 	if (!p)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) 		return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) 	for (i = 0; i < str_len; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 		const unsigned char c = p[i];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 		if (c == '\\')
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 			len += 2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 		else if (c > ' ' && c < 127)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 			len++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 		else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 			len += 4;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 	len++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 	/* Reserve space for appending "/". */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 	cp = kzalloc(len + 10, GFP_NOFS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 	if (!cp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 		return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 	cp0 = cp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 	p = str;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 	for (i = 0; i < str_len; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 		const unsigned char c = p[i];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 		if (c == '\\') {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 			*cp++ = '\\';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 			*cp++ = '\\';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 		} else if (c > ' ' && c < 127) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 			*cp++ = c;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 		} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 			*cp++ = '\\';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 			*cp++ = (c >> 6) + '0';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 			*cp++ = ((c >> 3) & 7) + '0';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 			*cp++ = (c & 7) + '0';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 	return cp0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69)  * tomoyo_encode - Encode binary string to ascii string.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71)  * @str: String in binary format.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73)  * Returns pointer to @str in ascii format on success, NULL otherwise.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75)  * This function uses kzalloc(), so caller must kfree() if this function
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76)  * didn't return NULL.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) char *tomoyo_encode(const char *str)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 	return str ? tomoyo_encode2(str, strlen(str)) : NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84)  * tomoyo_get_absolute_path - Get the path of a dentry but ignores chroot'ed root.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86)  * @path:   Pointer to "struct path".
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87)  * @buffer: Pointer to buffer to return value in.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88)  * @buflen: Sizeof @buffer.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90)  * Returns the buffer on success, an error code otherwise.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92)  * If dentry is a directory, trailing '/' is appended.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) static char *tomoyo_get_absolute_path(const struct path *path, char * const buffer,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 				      const int buflen)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 	char *pos = ERR_PTR(-ENOMEM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 	if (buflen >= 256) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 		/* go to whatever namespace root we are under */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 		pos = d_absolute_path(path, buffer, buflen - 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 		if (!IS_ERR(pos) && *pos == '/' && pos[1]) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 			struct inode *inode = d_backing_inode(path->dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 			if (inode && S_ISDIR(inode->i_mode)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 				buffer[buflen - 2] = '/';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 				buffer[buflen - 1] = '\0';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 	return pos;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115)  * tomoyo_get_dentry_path - Get the path of a dentry.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117)  * @dentry: Pointer to "struct dentry".
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118)  * @buffer: Pointer to buffer to return value in.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119)  * @buflen: Sizeof @buffer.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121)  * Returns the buffer on success, an error code otherwise.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123)  * If dentry is a directory, trailing '/' is appended.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) static char *tomoyo_get_dentry_path(struct dentry *dentry, char * const buffer,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 				    const int buflen)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 	char *pos = ERR_PTR(-ENOMEM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 	if (buflen >= 256) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 		pos = dentry_path_raw(dentry, buffer, buflen - 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 		if (!IS_ERR(pos) && *pos == '/' && pos[1]) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 			struct inode *inode = d_backing_inode(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 			if (inode && S_ISDIR(inode->i_mode)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 				buffer[buflen - 2] = '/';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 				buffer[buflen - 1] = '\0';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 	return pos;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145)  * tomoyo_get_local_path - Get the path of a dentry.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147)  * @dentry: Pointer to "struct dentry".
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148)  * @buffer: Pointer to buffer to return value in.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149)  * @buflen: Sizeof @buffer.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151)  * Returns the buffer on success, an error code otherwise.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) static char *tomoyo_get_local_path(struct dentry *dentry, char * const buffer,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 				   const int buflen)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 	struct super_block *sb = dentry->d_sb;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	char *pos = tomoyo_get_dentry_path(dentry, buffer, buflen);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 	if (IS_ERR(pos))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 		return pos;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 	/* Convert from $PID to self if $PID is current thread. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 	if (sb->s_magic == PROC_SUPER_MAGIC && *pos == '/') {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 		char *ep;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 		const pid_t pid = (pid_t) simple_strtoul(pos + 1, &ep, 10);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 		struct pid_namespace *proc_pidns = proc_pid_ns(sb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 		if (*ep == '/' && pid && pid ==
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 		    task_tgid_nr_ns(current, proc_pidns)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 			pos = ep - 5;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 			if (pos < buffer)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 				goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 			memmove(pos, "/self", 5);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 		goto prepend_filesystem_name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	/* Use filesystem name for unnamed devices. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 	if (!MAJOR(sb->s_dev))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 		goto prepend_filesystem_name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 	{
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 		struct inode *inode = d_backing_inode(sb->s_root);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 		 * Use filesystem name if filesystem does not support rename()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 		 * operation.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 		if (!inode->i_op->rename)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 			goto prepend_filesystem_name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 	/* Prepend device name. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 	{
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 		char name[64];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 		int name_len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 		const dev_t dev = sb->s_dev;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 		name[sizeof(name) - 1] = '\0';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 		snprintf(name, sizeof(name) - 1, "dev(%u,%u):", MAJOR(dev),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 			 MINOR(dev));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 		name_len = strlen(name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 		pos -= name_len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 		if (pos < buffer)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 			goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 		memmove(pos, name, name_len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 		return pos;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 	/* Prepend filesystem name. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) prepend_filesystem_name:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 	{
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 		const char *name = sb->s_type->name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 		const int name_len = strlen(name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 		pos -= name_len + 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 		if (pos < buffer)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 			goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 		memmove(pos, name, name_len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 		pos[name_len] = ':';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 	return pos;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 	return ERR_PTR(-ENOMEM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223)  * tomoyo_realpath_from_path - Returns realpath(3) of the given pathname but ignores chroot'ed root.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225)  * @path: Pointer to "struct path".
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227)  * Returns the realpath of the given @path on success, NULL otherwise.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229)  * If dentry is a directory, trailing '/' is appended.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230)  * Characters out of 0x20 < c < 0x7F range are converted to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231)  * \ooo style octal string.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232)  * Character \ is converted to \\ string.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234)  * These functions use kzalloc(), so the caller must call kfree()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235)  * if these functions didn't return NULL.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) char *tomoyo_realpath_from_path(const struct path *path)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) 	char *buf = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 	char *name = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) 	unsigned int buf_len = PAGE_SIZE / 2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) 	struct dentry *dentry = path->dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) 	struct super_block *sb;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) 	if (!dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 		return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 	sb = dentry->d_sb;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 	while (1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 		char *pos;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 		struct inode *inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 		buf_len <<= 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 		kfree(buf);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 		buf = kmalloc(buf_len, GFP_NOFS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 		if (!buf)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 		/* To make sure that pos is '\0' terminated. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 		buf[buf_len - 1] = '\0';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 		/* For "pipe:[\$]" and "socket:[\$]". */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 		if (dentry->d_op && dentry->d_op->d_dname) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 			pos = dentry->d_op->d_dname(dentry, buf, buf_len - 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 			goto encode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 		inode = d_backing_inode(sb->s_root);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 		 * Get local name for filesystems without rename() operation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) 		 * or dentry without vfsmount.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) 		if (!path->mnt ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 		    (!inode->i_op->rename &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 		     !(sb->s_type->fs_flags & FS_REQUIRES_DEV)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 			pos = tomoyo_get_local_path(path->dentry, buf,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 						    buf_len - 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 		/* Get absolute name for the rest. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 		else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 			pos = tomoyo_get_absolute_path(path, buf, buf_len - 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 			/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 			 * Fall back to local name if absolute name is not
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 			 * available.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 			 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 			if (pos == ERR_PTR(-EINVAL))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) 				pos = tomoyo_get_local_path(path->dentry, buf,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 							    buf_len - 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) encode:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) 		if (IS_ERR(pos))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) 			continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) 		name = tomoyo_encode(pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) 	kfree(buf);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) 	if (!name)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) 		tomoyo_warn_oom(__func__);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) 	return name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298)  * tomoyo_realpath_nofollow - Get realpath of a pathname.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300)  * @pathname: The pathname to solve.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302)  * Returns the realpath of @pathname on success, NULL otherwise.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) char *tomoyo_realpath_nofollow(const char *pathname)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) 	struct path path;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 	if (pathname && kern_path(pathname, 0, &path) == 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) 		char *buf = tomoyo_realpath_from_path(&path);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) 		path_put(&path);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) 		return buf;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) 	return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) }