diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/fonts/fonts.c | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/lib/fonts/fonts.c b/lib/fonts/fonts.c index 3fb76d185647..16e75c3d2a0f 100644 --- a/lib/fonts/fonts.c +++ b/lib/fonts/fonts.c @@ -14,7 +14,9 @@ #include <linux/container_of.h> #include <linux/font.h> +#include <linux/kd.h> #include <linux/module.h> +#include <linux/overflow.h> #include <linux/slab.h> #include <linux/string.h> #include <linux/types.h> @@ -23,6 +25,8 @@ #include <asm/setup.h> #endif +#define console_font_pitch(font) DIV_ROUND_UP((font)->width, 8) + /* * Helpers for font_data_t */ @@ -43,6 +47,64 @@ static void font_data_free(font_data_t *fd) } /** + * font_data_import - Allocates and initializes font data from user space + * @font: A font from user space + * @vpitch: The size of a single glyph in @font in bytes + * @calc_csum: An optional helper to calculate a chechsum + * + * Font data from user space must be translated to the kernel's format. The + * font's glyph geometry and data is provided in @font. The parameter @vpitch + * gives the number of bytes per glyph, including trailing bytes. + * + * The parameter @calc_csum is optional. Fbcon passes crc32() to calculate the + * font data's checksum. + * + * Returns: + * Newly initialized font data on success, or a pointer-encoded errno value otherwise. + */ +font_data_t *font_data_import(const struct console_font *font, unsigned int vpitch, + u32 (*calc_csum)(u32, const void *, size_t)) +{ + unsigned int pitch = console_font_pitch(font); + unsigned int h = font->height; + unsigned int charcount = font->charcount; + const unsigned char *data = font->data; + u32 csum = 0; + struct font_data *font_data; + int size, alloc_size; + unsigned int i; + font_data_t *fd; + + /* Check for integer overflow in font-size calculation */ + if (check_mul_overflow(h, pitch, &size) || + check_mul_overflow(size, charcount, &size)) + return ERR_PTR(-EINVAL); + + /* Check for overflow in allocation size calculation */ + if (check_add_overflow(sizeof(*font_data), size, &alloc_size)) + return ERR_PTR(-EINVAL); + + font_data = kmalloc(alloc_size, GFP_USER); + if (!font_data) + return ERR_PTR(-ENOMEM); + memset(font_data->extra, 0, sizeof(font_data->extra)); + + for (i = 0; i < charcount; ++i) + memcpy(font_data->data + i * h * pitch, data + i * vpitch * pitch, h * pitch); + + if (calc_csum) + csum = calc_csum(0, font_data->data, size); + + fd = font_data->data; + REFCOUNT(fd) = 1; /* start with reference acquired */ + FNTSIZE(fd) = size; + FNTSUM(fd) = csum; + + return fd; +} +EXPORT_SYMBOL_GPL(font_data_import); + +/** * font_data_get - Acquires a reference on font data * @fd: Font data * |