diff options
Diffstat (limited to 'kernel/module.c')
| -rw-r--r-- | kernel/module.c | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/kernel/module.c b/kernel/module.c index e7b4ff7e4fd0..8fa2600bde6a 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1520,18 +1520,34 @@ struct module_sect_attrs { struct module_sect_attr attrs[]; }; +#define MODULE_SECT_READ_SIZE (3 /* "0x", "\n" */ + (BITS_PER_LONG / 4)) static ssize_t module_sect_read(struct file *file, struct kobject *kobj, struct bin_attribute *battr, char *buf, loff_t pos, size_t count) { struct module_sect_attr *sattr = container_of(battr, struct module_sect_attr, battr); + char bounce[MODULE_SECT_READ_SIZE + 1]; + size_t wrote; if (pos != 0) return -EINVAL; - return sprintf(buf, "0x%px\n", - kallsyms_show_value(file->f_cred) ? (void *)sattr->address : NULL); + /* + * Since we're a binary read handler, we must account for the + * trailing NUL byte that sprintf will write: if "buf" is + * too small to hold the NUL, or the NUL is exactly the last + * byte, the read will look like it got truncated by one byte. + * Since there is no way to ask sprintf nicely to not write + * the NUL, we have to use a bounce buffer. + */ + wrote = scnprintf(bounce, sizeof(bounce), "0x%px\n", + kallsyms_show_value(file->f_cred) + ? (void *)sattr->address : NULL); + count = min(count, wrote); + memcpy(buf, bounce, count); + + return count; } static void free_sect_attrs(struct module_sect_attrs *sect_attrs) @@ -1580,7 +1596,7 @@ static void add_sect_attrs(struct module *mod, const struct load_info *info) goto out; sect_attrs->nsections++; sattr->battr.read = module_sect_read; - sattr->battr.size = 3 /* "0x", "\n" */ + (BITS_PER_LONG / 4); + sattr->battr.size = MODULE_SECT_READ_SIZE; sattr->battr.attr.mode = 0400; *(gattr++) = &(sattr++)->battr; } |