diff options
| author | Kees Cook <kees+treewide@kernel.org> | 2026-09-02 15:31:14 -0700 |
|---|---|---|
| committer | Kees Cook <kees@kernel.org> | 2026-09-04 21:37:00 -0700 |
| commit | 3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d (patch) | |
| tree | c65086f9bdcd48c6360fb7cb4598bca084da1f32 /security/tomoyo/realpath.c | |
| download | linux-stable-3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d.tar.gz linux-stable-3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d.zip | |
treewide: refresh kmalloc_obj() conversionsgrafted
This is another run of the Coccinelle script for converting kmalloc()
family of allocations to kmalloc_obj() via the existing rules in
scripts/coccinelle/api/kmalloc_objs.cocci
This catches both the set of kmalloc() uses added since the first
kmalloc_obj() conversions in v7.0 and adds a large group missed in the
first pass due to Coccinelle not interacting well with the cleanup.h
scoped_...() family of macros[1]. I worked around this with spatch's
"--macro-file" argument to a file with all the scoped_...() macros mapped
to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control
flow indicator I could find.
Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc,
riscv, and s390 with no new warnings.
Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1]
Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2]
Signed-off-by: Kees Cook <kees+treewide@kernel.org>
Diffstat (limited to 'security/tomoyo/realpath.c')
| -rw-r--r-- | security/tomoyo/realpath.c | 310 |
1 files changed, 310 insertions, 0 deletions
diff --git a/security/tomoyo/realpath.c b/security/tomoyo/realpath.c new file mode 100644 index 000000000..1c483ee7f --- /dev/null +++ b/security/tomoyo/realpath.c @@ -0,0 +1,310 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * security/tomoyo/realpath.c + * + * Copyright (C) 2005-2011 NTT DATA CORPORATION + */ + +#include "common.h" +#include <linux/magic.h> +#include <linux/proc_fs.h> + +/** + * tomoyo_encode2 - Encode binary string to ascii string. + * + * @str: String in binary format. + * @str_len: Size of @str in byte. + * + * Returns pointer to @str in ascii format on success, NULL otherwise. + * + * This function uses kzalloc(), so caller must kfree() if this function + * didn't return NULL. + */ +char *tomoyo_encode2(const char *str, int str_len) +{ + int i; + int len = 0; + const char *p = str; + char *cp; + char *cp0; + + if (!p) + return NULL; + for (i = 0; i < str_len; i++) { + const unsigned char c = p[i]; + + if (c == '\\') + len += 2; + else if (c > ' ' && c < 127) + len++; + else + len += 4; + } + len++; + /* Reserve space for appending "/". */ + cp = kzalloc(len + 10, GFP_NOFS); + if (!cp) + return NULL; + cp0 = cp; + p = str; + for (i = 0; i < str_len; i++) { + const unsigned char c = p[i]; + + if (c == '\\') { + *cp++ = '\\'; + *cp++ = '\\'; + } else if (c > ' ' && c < 127) { + *cp++ = c; + } else { + *cp++ = '\\'; + *cp++ = (c >> 6) + '0'; + *cp++ = ((c >> 3) & 7) + '0'; + *cp++ = (c & 7) + '0'; + } + } + return cp0; +} + +/** + * tomoyo_encode - Encode binary string to ascii string. + * + * @str: String in binary format. + * + * Returns pointer to @str in ascii format on success, NULL otherwise. + * + * This function uses kzalloc(), so caller must kfree() if this function + * didn't return NULL. + */ +char *tomoyo_encode(const char *str) +{ + return str ? tomoyo_encode2(str, strlen(str)) : NULL; +} + +/** + * tomoyo_get_absolute_path - Get the path of a dentry but ignores chroot'ed root. + * + * @path: Pointer to "struct path". + * @buffer: Pointer to buffer to return value in. + * @buflen: Sizeof @buffer. + * + * Returns the buffer on success, an error code otherwise. + * + * If dentry is a directory, trailing '/' is appended. + */ +static char *tomoyo_get_absolute_path(const struct path *path, char * const buffer, + const int buflen) +{ + char *pos = ERR_PTR(-ENOMEM); + + if (buflen >= 256) { + /* go to whatever namespace root we are under */ + pos = d_absolute_path(path, buffer, buflen - 1); + if (!IS_ERR(pos) && *pos == '/' && pos[1]) { + struct inode *inode = d_backing_inode(path->dentry); + + if (inode && S_ISDIR(inode->i_mode)) { + buffer[buflen - 2] = '/'; + buffer[buflen - 1] = '\0'; + } + } + } + return pos; +} + +/** + * tomoyo_get_dentry_path - Get the path of a dentry. + * + * @dentry: Pointer to "struct dentry". + * @buffer: Pointer to buffer to return value in. + * @buflen: Sizeof @buffer. + * + * Returns the buffer on success, an error code otherwise. + * + * If dentry is a directory, trailing '/' is appended. + */ +static char *tomoyo_get_dentry_path(struct dentry *dentry, char * const buffer, + const int buflen) +{ + char *pos = ERR_PTR(-ENOMEM); + + if (buflen >= 256) { + pos = dentry_path_raw(dentry, buffer, buflen - 1); + if (!IS_ERR(pos) && *pos == '/' && pos[1]) { + struct inode *inode = d_backing_inode(dentry); + + if (inode && S_ISDIR(inode->i_mode)) { + buffer[buflen - 2] = '/'; + buffer[buflen - 1] = '\0'; + } + } + } + return pos; +} + +/** + * tomoyo_get_local_path - Get the path of a dentry. + * + * @dentry: Pointer to "struct dentry". + * @buffer: Pointer to buffer to return value in. + * @buflen: Sizeof @buffer. + * + * Returns the buffer on success, an error code otherwise. + */ +static char *tomoyo_get_local_path(struct dentry *dentry, char * const buffer, + const int buflen) +{ + struct super_block *sb = dentry->d_sb; + char *pos = tomoyo_get_dentry_path(dentry, buffer, buflen); + + if (IS_ERR(pos)) + return pos; + /* Convert from $PID to self if $PID is current thread. */ + if (sb->s_magic == PROC_SUPER_MAGIC && *pos == '/') { + char *ep; + const pid_t pid = (pid_t) simple_strtoul(pos + 1, &ep, 10); + struct pid_namespace *proc_pidns = proc_pid_ns(sb); + + if (*ep == '/' && pid && pid == + task_tgid_nr_ns(current, proc_pidns)) { + pos = ep - 5; + if (pos < buffer) + goto out; + memmove(pos, "/self", 5); + } + goto prepend_filesystem_name; + } + /* Use filesystem name for unnamed devices. */ + if (!MAJOR(sb->s_dev)) + goto prepend_filesystem_name; + { + struct inode *inode = d_backing_inode(sb->s_root); + + /* + * Use filesystem name if filesystem does not support rename() + * operation. + */ + if (!inode->i_op->rename) + goto prepend_filesystem_name; + } + /* Prepend device name. */ + { + char name[64]; + int name_len; + const dev_t dev = sb->s_dev; + + name[sizeof(name) - 1] = '\0'; + snprintf(name, sizeof(name) - 1, "dev(%u,%u):", MAJOR(dev), + MINOR(dev)); + name_len = strlen(name); + pos -= name_len; + if (pos < buffer) + goto out; + memmove(pos, name, name_len); + return pos; + } + /* Prepend filesystem name. */ +prepend_filesystem_name: + { + const char *name = sb->s_type->name; + const int name_len = strlen(name); + + pos -= name_len + 1; + if (pos < buffer) + goto out; + memmove(pos, name, name_len); + pos[name_len] = ':'; + } + return pos; +out: + return ERR_PTR(-ENOMEM); +} + +/** + * tomoyo_realpath_from_path - Returns realpath(3) of the given pathname but ignores chroot'ed root. + * + * @path: Pointer to "struct path". + * + * Returns the realpath of the given @path on success, NULL otherwise. + * + * If dentry is a directory, trailing '/' is appended. + * Characters out of 0x20 < c < 0x7F range are converted to + * \ooo style octal string. + * Character \ is converted to \\ string. + * + * These functions use kzalloc(), so the caller must call kfree() + * if these functions didn't return NULL. + */ +char *tomoyo_realpath_from_path(const struct path *path) +{ + char *buf = NULL; + char *name = NULL; + unsigned int buf_len = PAGE_SIZE / 2; + struct dentry *dentry = path->dentry; + struct super_block *sb = dentry->d_sb; + + while (1) { + char *pos; + struct inode *inode; + + buf_len <<= 1; + kfree(buf); + buf = kmalloc(buf_len, GFP_NOFS); + if (!buf) + break; + /* To make sure that pos is '\0' terminated. */ + buf[buf_len - 1] = '\0'; + /* For "pipe:[\$]" and "socket:[\$]". */ + if (dentry->d_op && dentry->d_op->d_dname) { + pos = dentry->d_op->d_dname(dentry, buf, buf_len - 1); + goto encode; + } + inode = d_backing_inode(sb->s_root); + /* + * Get local name for filesystems without rename() operation + */ + if ((!inode->i_op->rename && + !(sb->s_type->fs_flags & FS_REQUIRES_DEV))) + pos = tomoyo_get_local_path(path->dentry, buf, + buf_len - 1); + /* Get absolute name for the rest. */ + else { + pos = tomoyo_get_absolute_path(path, buf, buf_len - 1); + /* + * Fall back to local name if absolute name is not + * available. + */ + if (pos == ERR_PTR(-EINVAL)) + pos = tomoyo_get_local_path(path->dentry, buf, + buf_len - 1); + } +encode: + if (IS_ERR(pos)) + continue; + name = tomoyo_encode(pos); + break; + } + kfree(buf); + if (!name) + tomoyo_warn_oom(__func__); + return name; +} + +/** + * tomoyo_realpath_nofollow - Get realpath of a pathname. + * + * @pathname: The pathname to solve. + * + * Returns the realpath of @pathname on success, NULL otherwise. + */ +char *tomoyo_realpath_nofollow(const char *pathname) +{ + struct path path; + + if (pathname && kern_path(pathname, 0, &path) == 0) { + char *buf = tomoyo_realpath_from_path(&path); + + path_put(&path); + return buf; + } + return NULL; +} |
