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-rw-r--r--fs/binfmt_misc.c393
1 files changed, 248 insertions, 145 deletions
diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index fd8beb9657a2..70789e198dea 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -1,21 +1,14 @@
/*
- * binfmt_misc.c
+ * binfmt_misc.c
*
- * Copyright (C) 1997 Richard Günther
+ * Copyright (C) 1997 Richard Günther
*
- * binfmt_misc detects binaries via a magic or filename extension and invokes
- * a specified wrapper. This should obsolete binfmt_java, binfmt_em86 and
- * binfmt_mz.
- *
- * 1997-04-25 first version
- * [...]
- * 1997-05-19 cleanup
- * 1997-06-26 hpa: pass the real filename rather than argv[0]
- * 1997-06-30 minor cleanup
- * 1997-08-09 removed extension stripping, locking cleanup
- * 2001-02-28 AV: rewritten into something that resembles C. Original didn't.
+ * binfmt_misc detects binaries via a magic or filename extension and invokes
+ * a specified wrapper. See Documentation/binfmt_misc.txt for more details.
*/
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
@@ -30,8 +23,13 @@
#include <linux/mount.h>
#include <linux/syscalls.h>
#include <linux/fs.h>
+#include <linux/uaccess.h>
-#include <asm/uaccess.h>
+#ifdef DEBUG
+# define USE_DEBUG 1
+#else
+# define USE_DEBUG 0
+#endif
enum {
VERBOSE_STATUS = 1 /* make it zero to save 400 bytes kernel memory */
@@ -41,9 +39,9 @@ static LIST_HEAD(entries);
static int enabled = 1;
enum {Enabled, Magic};
-#define MISC_FMT_PRESERVE_ARGV0 (1<<31)
-#define MISC_FMT_OPEN_BINARY (1<<30)
-#define MISC_FMT_CREDENTIALS (1<<29)
+#define MISC_FMT_PRESERVE_ARGV0 (1 << 31)
+#define MISC_FMT_OPEN_BINARY (1 << 30)
+#define MISC_FMT_CREDENTIALS (1 << 29)
typedef struct {
struct list_head list;
@@ -87,20 +85,24 @@ static Node *check_file(struct linux_binprm *bprm)
char *p = strrchr(bprm->interp, '.');
struct list_head *l;
+ /* Walk all the registered handlers. */
list_for_each(l, &entries) {
Node *e = list_entry(l, Node, list);
char *s;
int j;
+ /* Make sure this one is currently enabled. */
if (!test_bit(Enabled, &e->flags))
continue;
+ /* Do matching based on extension if applicable. */
if (!test_bit(Magic, &e->flags)) {
if (p && !strcmp(e->magic, p + 1))
return e;
continue;
}
+ /* Do matching based on magic & mask. */
s = bprm->buf + e->offset;
if (e->mask) {
for (j = 0; j < e->size; j++)
@@ -123,7 +125,7 @@ static Node *check_file(struct linux_binprm *bprm)
static int load_misc_binary(struct linux_binprm *bprm)
{
Node *fmt;
- struct file * interp_file = NULL;
+ struct file *interp_file = NULL;
char iname[BINPRM_BUF_SIZE];
const char *iname_addr = iname;
int retval;
@@ -131,7 +133,7 @@ static int load_misc_binary(struct linux_binprm *bprm)
retval = -ENOEXEC;
if (!enabled)
- goto _ret;
+ goto ret;
/* to keep locking time low, we copy the interpreter string */
read_lock(&entries_lock);
@@ -140,25 +142,26 @@ static int load_misc_binary(struct linux_binprm *bprm)
strlcpy(iname, fmt->interpreter, BINPRM_BUF_SIZE);
read_unlock(&entries_lock);
if (!fmt)
- goto _ret;
+ goto ret;
if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) {
retval = remove_arg_zero(bprm);
if (retval)
- goto _ret;
+ goto ret;
}
if (fmt->flags & MISC_FMT_OPEN_BINARY) {
/* if the binary should be opened on behalf of the
* interpreter than keep it open and assign descriptor
- * to it */
- fd_binary = get_unused_fd();
- if (fd_binary < 0) {
- retval = fd_binary;
- goto _ret;
- }
- fd_install(fd_binary, bprm->file);
+ * to it
+ */
+ fd_binary = get_unused_fd_flags(0);
+ if (fd_binary < 0) {
+ retval = fd_binary;
+ goto ret;
+ }
+ fd_install(fd_binary, bprm->file);
/* if the binary is not readable than enforce mm->dumpable=0
regardless of the interpreter's permissions */
@@ -171,32 +174,32 @@ static int load_misc_binary(struct linux_binprm *bprm)
bprm->interp_flags |= BINPRM_FLAGS_EXECFD;
bprm->interp_data = fd_binary;
- } else {
- allow_write_access(bprm->file);
- fput(bprm->file);
- bprm->file = NULL;
- }
+ } else {
+ allow_write_access(bprm->file);
+ fput(bprm->file);
+ bprm->file = NULL;
+ }
/* make argv[1] be the path to the binary */
- retval = copy_strings_kernel (1, &bprm->interp, bprm);
+ retval = copy_strings_kernel(1, &bprm->interp, bprm);
if (retval < 0)
- goto _error;
+ goto error;
bprm->argc++;
/* add the interp as argv[0] */
- retval = copy_strings_kernel (1, &iname_addr, bprm);
+ retval = copy_strings_kernel(1, &iname_addr, bprm);
if (retval < 0)
- goto _error;
- bprm->argc ++;
+ goto error;
+ bprm->argc++;
/* Update interp in case binfmt_script needs it. */
retval = bprm_change_interp(iname, bprm);
if (retval < 0)
- goto _error;
+ goto error;
- interp_file = open_exec (iname);
- retval = PTR_ERR (interp_file);
- if (IS_ERR (interp_file))
- goto _error;
+ interp_file = open_exec(iname);
+ retval = PTR_ERR(interp_file);
+ if (IS_ERR(interp_file))
+ goto error;
bprm->file = interp_file;
if (fmt->flags & MISC_FMT_CREDENTIALS) {
@@ -207,23 +210,23 @@ static int load_misc_binary(struct linux_binprm *bprm)
memset(bprm->buf, 0, BINPRM_BUF_SIZE);
retval = kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE);
} else
- retval = prepare_binprm (bprm);
+ retval = prepare_binprm(bprm);
if (retval < 0)
- goto _error;
+ goto error;
retval = search_binary_handler(bprm);
if (retval < 0)
- goto _error;
+ goto error;
-_ret:
+ret:
return retval;
-_error:
+error:
if (fd_binary > 0)
sys_close(fd_binary);
bprm->interp_flags = 0;
bprm->interp_data = 0;
- goto _ret;
+ goto ret;
}
/* Command parsers */
@@ -250,36 +253,40 @@ static char *scanarg(char *s, char del)
return s;
}
-static char * check_special_flags (char * sfs, Node * e)
+static char *check_special_flags(char *sfs, Node *e)
{
- char * p = sfs;
+ char *p = sfs;
int cont = 1;
/* special flags */
while (cont) {
switch (*p) {
- case 'P':
- p++;
- e->flags |= MISC_FMT_PRESERVE_ARGV0;
- break;
- case 'O':
- p++;
- e->flags |= MISC_FMT_OPEN_BINARY;
- break;
- case 'C':
- p++;
- /* this flags also implies the
- open-binary flag */
- e->flags |= (MISC_FMT_CREDENTIALS |
- MISC_FMT_OPEN_BINARY);
- break;
- default:
- cont = 0;
+ case 'P':
+ pr_debug("register: flag: P (preserve argv0)\n");
+ p++;
+ e->flags |= MISC_FMT_PRESERVE_ARGV0;
+ break;
+ case 'O':
+ pr_debug("register: flag: O (open binary)\n");
+ p++;
+ e->flags |= MISC_FMT_OPEN_BINARY;
+ break;
+ case 'C':
+ pr_debug("register: flag: C (preserve creds)\n");
+ p++;
+ /* this flags also implies the
+ open-binary flag */
+ e->flags |= (MISC_FMT_CREDENTIALS |
+ MISC_FMT_OPEN_BINARY);
+ break;
+ default:
+ cont = 0;
}
}
return p;
}
+
/*
* This registers a new binary format, it recognises the syntax
* ':name:type:offset:magic:mask:interpreter:flags'
@@ -292,6 +299,8 @@ static Node *create_entry(const char __user *buffer, size_t count)
char *buf, *p;
char del;
+ pr_debug("register: received %zu bytes\n", count);
+
/* some sanity checks */
err = -EINVAL;
if ((count < 11) || (count > MAX_REGISTER_LENGTH))
@@ -299,7 +308,7 @@ static Node *create_entry(const char __user *buffer, size_t count)
err = -ENOMEM;
memsize = sizeof(Node) + count + 8;
- e = kmalloc(memsize, GFP_USER);
+ e = kmalloc(memsize, GFP_KERNEL);
if (!e)
goto out;
@@ -307,98 +316,175 @@ static Node *create_entry(const char __user *buffer, size_t count)
memset(e, 0, sizeof(Node));
if (copy_from_user(buf, buffer, count))
- goto Efault;
+ goto efault;
del = *p++; /* delimeter */
- memset(buf+count, del, 8);
+ pr_debug("register: delim: %#x {%c}\n", del, del);
+
+ /* Pad the buffer with the delim to simplify parsing below. */
+ memset(buf + count, del, 8);
+ /* Parse the 'name' field. */
e->name = p;
p = strchr(p, del);
if (!p)
- goto Einval;
+ goto einval;
*p++ = '\0';
if (!e->name[0] ||
!strcmp(e->name, ".") ||
!strcmp(e->name, "..") ||
strchr(e->name, '/'))
- goto Einval;
+ goto einval;
+
+ pr_debug("register: name: {%s}\n", e->name);
+
+ /* Parse the 'type' field. */
switch (*p++) {
- case 'E': e->flags = 1<<Enabled; break;
- case 'M': e->flags = (1<<Enabled) | (1<<Magic); break;
- default: goto Einval;
+ case 'E':
+ pr_debug("register: type: E (extension)\n");
+ e->flags = 1 << Enabled;
+ break;
+ case 'M':
+ pr_debug("register: type: M (magic)\n");
+ e->flags = (1 << Enabled) | (1 << Magic);
+ break;
+ default:
+ goto einval;
}
if (*p++ != del)
- goto Einval;
+ goto einval;
+
if (test_bit(Magic, &e->flags)) {
- char *s = strchr(p, del);
+ /* Handle the 'M' (magic) format. */
+ char *s;
+
+ /* Parse the 'offset' field. */
+ s = strchr(p, del);
if (!s)
- goto Einval;
+ goto einval;
*s++ = '\0';
e->offset = simple_strtoul(p, &p, 10);
if (*p++)
- goto Einval;
+ goto einval;
+ pr_debug("register: offset: %#x\n", e->offset);
+
+ /* Parse the 'magic' field. */
e->magic = p;
p = scanarg(p, del);
if (!p)
- goto Einval;
+ goto einval;
p[-1] = '\0';
- if (!e->magic[0])
- goto Einval;
+ if (p == e->magic)
+ goto einval;
+ if (USE_DEBUG)
+ print_hex_dump_bytes(
+ KBUILD_MODNAME ": register: magic[raw]: ",
+ DUMP_PREFIX_NONE, e->magic, p - e->magic);
+
+ /* Parse the 'mask' field. */
e->mask = p;
p = scanarg(p, del);
if (!p)
- goto Einval;
+ goto einval;
p[-1] = '\0';
- if (!e->mask[0])
+ if (p == e->mask) {
e->mask = NULL;
+ pr_debug("register: mask[raw]: none\n");
+ } else if (USE_DEBUG)
+ print_hex_dump_bytes(
+ KBUILD_MODNAME ": register: mask[raw]: ",
+ DUMP_PREFIX_NONE, e->mask, p - e->mask);
+
+ /*
+ * Decode the magic & mask fields.
+ * Note: while we might have accepted embedded NUL bytes from
+ * above, the unescape helpers here will stop at the first one
+ * it encounters.
+ */
e->size = string_unescape_inplace(e->magic, UNESCAPE_HEX);
if (e->mask &&
string_unescape_inplace(e->mask, UNESCAPE_HEX) != e->size)
- goto Einval;
+ goto einval;
if (e->size + e->offset > BINPRM_BUF_SIZE)
- goto Einval;
+ goto einval;
+ pr_debug("register: magic/mask length: %i\n", e->size);
+ if (USE_DEBUG) {
+ print_hex_dump_bytes(
+ KBUILD_MODNAME ": register: magic[decoded]: ",
+ DUMP_PREFIX_NONE, e->magic, e->size);
+
+ if (e->mask) {
+ int i;
+ char *masked = kmalloc(e->size, GFP_KERNEL);
+
+ print_hex_dump_bytes(
+ KBUILD_MODNAME ": register: mask[decoded]: ",
+ DUMP_PREFIX_NONE, e->mask, e->size);
+
+ if (masked) {
+ for (i = 0; i < e->size; ++i)
+ masked[i] = e->magic[i] & e->mask[i];
+ print_hex_dump_bytes(
+ KBUILD_MODNAME ": register: magic[masked]: ",
+ DUMP_PREFIX_NONE, masked, e->size);
+
+ kfree(masked);
+ }
+ }
+ }
} else {
+ /* Handle the 'E' (extension) format. */
+
+ /* Skip the 'offset' field. */
p = strchr(p, del);
if (!p)
- goto Einval;
+ goto einval;
*p++ = '\0';
+
+ /* Parse the 'magic' field. */
e->magic = p;
p = strchr(p, del);
if (!p)
- goto Einval;
+ goto einval;
*p++ = '\0';
if (!e->magic[0] || strchr(e->magic, '/'))
- goto Einval;
+ goto einval;
+ pr_debug("register: extension: {%s}\n", e->magic);
+
+ /* Skip the 'mask' field. */
p = strchr(p, del);
if (!p)
- goto Einval;
+ goto einval;
*p++ = '\0';
}
+
+ /* Parse the 'interpreter' field. */
e->interpreter = p;
p = strchr(p, del);
if (!p)
- goto Einval;
+ goto einval;
*p++ = '\0';
if (!e->interpreter[0])
- goto Einval;
-
-
- p = check_special_flags (p, e);
+ goto einval;
+ pr_debug("register: interpreter: {%s}\n", e->interpreter);
+ /* Parse the 'flags' field. */
+ p = check_special_flags(p, e);
if (*p == '\n')
p++;
if (p != buf + count)
- goto Einval;
+ goto einval;
+
return e;
out:
return ERR_PTR(err);
-Efault:
+efault:
kfree(e);
return ERR_PTR(-EFAULT);
-Einval:
+einval:
kfree(e);
return ERR_PTR(-EINVAL);
}
@@ -417,7 +503,7 @@ static int parse_command(const char __user *buffer, size_t count)
return -EFAULT;
if (!count)
return 0;
- if (s[count-1] == '\n')
+ if (s[count - 1] == '\n')
count--;
if (count == 1 && s[0] == '0')
return 1;
@@ -434,7 +520,7 @@ static void entry_status(Node *e, char *page)
{
char *dp;
char *status = "disabled";
- const char * flags = "flags: ";
+ const char *flags = "flags: ";
if (test_bit(Enabled, &e->flags))
status = "enabled";
@@ -448,19 +534,15 @@ static void entry_status(Node *e, char *page)
dp = page + strlen(page);
/* print the special flags */
- sprintf (dp, "%s", flags);
- dp += strlen (flags);
- if (e->flags & MISC_FMT_PRESERVE_ARGV0) {
- *dp ++ = 'P';
- }
- if (e->flags & MISC_FMT_OPEN_BINARY) {
- *dp ++ = 'O';
- }
- if (e->flags & MISC_FMT_CREDENTIALS) {
- *dp ++ = 'C';
- }
- *dp ++ = '\n';
-
+ sprintf(dp, "%s", flags);
+ dp += strlen(flags);
+ if (e->flags & MISC_FMT_PRESERVE_ARGV0)
+ *dp++ = 'P';
+ if (e->flags & MISC_FMT_OPEN_BINARY)
+ *dp++ = 'O';
+ if (e->flags & MISC_FMT_CREDENTIALS)
+ *dp++ = 'C';
+ *dp++ = '\n';
if (!test_bit(Magic, &e->flags)) {
sprintf(dp, "extension .%s\n", e->magic);
@@ -488,7 +570,7 @@ static void entry_status(Node *e, char *page)
static struct inode *bm_get_inode(struct super_block *sb, int mode)
{
- struct inode * inode = new_inode(sb);
+ struct inode *inode = new_inode(sb);
if (inode) {
inode->i_ino = get_next_ino();
@@ -528,13 +610,14 @@ static void kill_node(Node *e)
/* /<entry> */
static ssize_t
-bm_entry_read(struct file * file, char __user * buf, size_t nbytes, loff_t *ppos)
+bm_entry_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
{
Node *e = file_inode(file)->i_private;
ssize_t res;
char *page;
- if (!(page = (char*) __get_free_page(GFP_KERNEL)))
+ page = (char *) __get_free_page(GFP_KERNEL);
+ if (!page)
return -ENOMEM;
entry_status(e, page);
@@ -553,20 +636,28 @@ static ssize_t bm_entry_write(struct file *file, const char __user *buffer,
int res = parse_command(buffer, count);
switch (res) {
- case 1: clear_bit(Enabled, &e->flags);
- break;
- case 2: set_bit(Enabled, &e->flags);
- break;
- case 3: root = dget(file->f_path.dentry->d_sb->s_root);
- mutex_lock(&root->d_inode->i_mutex);
-
- kill_node(e);
-
- mutex_unlock(&root->d_inode->i_mutex);
- dput(root);
- break;
- default: return res;
+ case 1:
+ /* Disable this handler. */
+ clear_bit(Enabled, &e->flags);
+ break;
+ case 2:
+ /* Enable this handler. */
+ set_bit(Enabled, &e->flags);
+ break;
+ case 3:
+ /* Delete this handler. */
+ root = dget(file->f_path.dentry->d_sb->s_root);
+ mutex_lock(&root->d_inode->i_mutex);
+
+ kill_node(e);
+
+ mutex_unlock(&root->d_inode->i_mutex);
+ dput(root);
+ break;
+ default:
+ return res;
}
+
return count;
}
@@ -654,26 +745,36 @@ bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s));
}
-static ssize_t bm_status_write(struct file * file, const char __user * buffer,
+static ssize_t bm_status_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos)
{
int res = parse_command(buffer, count);
struct dentry *root;
switch (res) {
- case 1: enabled = 0; break;
- case 2: enabled = 1; break;
- case 3: root = dget(file->f_path.dentry->d_sb->s_root);
- mutex_lock(&root->d_inode->i_mutex);
-
- while (!list_empty(&entries))
- kill_node(list_entry(entries.next, Node, list));
-
- mutex_unlock(&root->d_inode->i_mutex);
- dput(root);
- break;
- default: return res;
+ case 1:
+ /* Disable all handlers. */
+ enabled = 0;
+ break;
+ case 2:
+ /* Enable all handlers. */
+ enabled = 1;
+ break;
+ case 3:
+ /* Delete all handlers. */
+ root = dget(file->f_path.dentry->d_sb->s_root);
+ mutex_lock(&root->d_inode->i_mutex);
+
+ while (!list_empty(&entries))
+ kill_node(list_entry(entries.next, Node, list));
+
+ mutex_unlock(&root->d_inode->i_mutex);
+ dput(root);
+ break;
+ default:
+ return res;
}
+
return count;
}
@@ -690,14 +791,16 @@ static const struct super_operations s_ops = {
.evict_inode = bm_evict_inode,
};
-static int bm_fill_super(struct super_block * sb, void * data, int silent)
+static int bm_fill_super(struct super_block *sb, void *data, int silent)
{
+ int err;
static struct tree_descr bm_files[] = {
[2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO},
[3] = {"register", &bm_register_operations, S_IWUSR},
/* last one */ {""}
};
- int err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files);
+
+ err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files);
if (!err)
sb->s_op = &s_ops;
return err;
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-24 19:43:27 +0000