"value":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: update orig_path in ext4_find_extent()\n\nIn ext4_find_extent(), if the path is not big enough, we free it and set\n*orig_path to NULL. But after reallocating and successfully initializing\nthe path, we don't update *orig_path, in which case the caller gets a\nvalid path but a NULL ppath, and this may cause a NULL pointer dereference\nor a path memory leak. For example:\n\next4_split_extent\n path = *ppath = 2000\n ext4_find_extent\n if (depth > path[0].p_maxdepth)\n kfree(path = 2000);\n *orig_path = path = NULL;\n path = kcalloc() = 3000\n ext4_split_extent_at(*ppath = NULL)\n path = *ppath;\n ex = path[depth].p_ext;\n // NULL pointer dereference!\n\n==================================================================\nBUG: kernel NULL pointer dereference, address: 0000000000000010\nCPU: 6 UID: 0 PID: 576 Comm: fsstress Not tainted 6.11.0-rc2-dirty #847\nRIP: 0010:ext4_split_extent_at+0x6d/0x560\nCall Trace:\n <TASK>\n ext4_split_extent.isra.0+0xcb/0x1b0\n ext4_ext_convert_to_initialized+0x168/0x6c0\n ext4_ext_handle_unwritten_extents+0x325/0x4d0\n ext4_ext_map_blocks+0x520/0xdb0\n ext4_map_blocks+0x2b0/0x690\n ext4_iomap_begin+0x20e/0x2c0\n[...]\n==================================================================\n\nTherefore, *orig_path is updated when the extent lookup succeeds, so that\nthe caller can safely use path or *ppath."
"value":"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ext4: actualizaci\u00f3n de orig_path en ext4_find_extent() En ext4_find_extent(), si la ruta no es lo suficientemente grande, la liberamos y establecemos *orig_path en NULL. Pero despu\u00e9s de reasignar e inicializar correctamente la ruta, no actualizamos *orig_path, en cuyo caso el llamador obtiene una ruta v\u00e1lida pero un ppath NULL, y esto puede causar una desreferencia de puntero NULL o una p\u00e9rdida de memoria de ruta. Por ejemplo: ext4_split_extent path = *ppath = 2000 ext4_find_extent if (depth > path[0].p_maxdepth) kfree(path = 2000); *orig_path = path = NULL; path = kcalloc() = 3000 ext4_split_extent_at(*ppath = NULL) path = *ppath; ex = path[depth].p_ext; // \u00a1Desreferencia de puntero NULL! ===================================================================== ERROR: Desreferencia de puntero NULL del n\u00facleo, direcci\u00f3n: 000000000000010 CPU: 6 UID: 0 PID: 576 Comm: fsstress No contaminado 6.11.0-rc2-dirty #847 RIP: 0010:ext4_split_extent_at+0x6d/0x560 Rastreo de llamada: ext4_split_extent.isra.0+0xcb/0x1b0 ext4_ext_convert_to_initialized+0x168/0x6c0 ext4_ext_handle_unwritten_extents+0x325/0x4d0 ext4_ext_map_blocks+0x520/0xdb0 ext4_map_blocks+0x2b0/0x690 ext4_iomap_begin+0x20e/0x2c0 [...] ====================================================================== Por lo tanto, *orig_path se actualiza cuando la b\u00fasqueda de extensi\u00f3n tiene \u00e9xito, de modo que el llamador puede usar path o *ppath de forma segura."
