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modules: lvgl: fix buffer overflow when using monochrome displays

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In lvgl_transform_buffer() the pixel map buffer start address is
modified to skip the library color palette header but the memcpy size
argument was not modified accordingly thus causing writes beyond buffer
reserved space.

Signed-off-by: Johan Lafon <johan.lafon@syslinbit.com>
This commit is contained in:
Johan Lafon 2025-01-14 18:29:06 +01:00 committed by Benjamin Cabé
parent 153f5b6382
commit 6043af638d
1 changed files with 6 additions and 3 deletions
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9
modules/lvgl/lvgl_display_mono.c
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@ -9,6 +9,8 @@
#include <string.h> #include <string.h>
#include "lvgl_display.h" #include "lvgl_display.h"
#define COLOR_PALETTE_HEADER_SIZE (8)
static uint8_t *mono_conv_buf; static uint8_t *mono_conv_buf;
static uint32_t mono_conv_buf_size; static uint32_t mono_conv_buf_size;
@ -50,8 +52,9 @@ static void lvgl_transform_buffer(uint8_t **px_map, uint32_t width, uint32_t hei
memset(mono_conv_buf, clear_color, mono_conv_buf_size); memset(mono_conv_buf, clear_color, mono_conv_buf_size);
/* Needed because LVGL reserves 2x4 bytes in the buffer for the color palette. */ /* Needed because LVGL reserves some bytes in the buffer for the color palette. */
*px_map += 8; *px_map += COLOR_PALETTE_HEADER_SIZE;
uint8_t *src_buf = *px_map; uint8_t *src_buf = *px_map;
uint32_t stride = (width + CONFIG_LV_DRAW_BUF_STRIDE_ALIGN - 1) & uint32_t stride = (width + CONFIG_LV_DRAW_BUF_STRIDE_ALIGN - 1) &
~(CONFIG_LV_DRAW_BUF_STRIDE_ALIGN - 1); ~(CONFIG_LV_DRAW_BUF_STRIDE_ALIGN - 1);
@ -67,7 +70,7 @@ static void lvgl_transform_buffer(uint8_t **px_map, uint32_t width, uint32_t hei
} }
} }
memcpy(src_buf, mono_conv_buf, mono_conv_buf_size); memcpy(src_buf, mono_conv_buf, mono_conv_buf_size - COLOR_PALETTE_HEADER_SIZE);
} }
void lvgl_flush_cb_mono(lv_display_t *display, const lv_area_t *area, uint8_t *px_map) void lvgl_flush_cb_mono(lv_display_t *display, const lv_area_t *area, uint8_t *px_map)