On Tue, Nov 29, 2016 at 01:57:17PM +0800, Eryu Guan wrote: > Ralf Spenneberg reported that he hit a kernel crash when mounting a > modified ext4 image. And it turns out that kernel crashed when > calculating fs overhead (ext4_calculate_overhead()), this is because > the image has very large s_first_meta_bg (debug code shows it's > 842150400), and ext4 overruns the memory in count_overhead() when > setting bitmap buffer, which is PAGE_SIZE. >... > Fix it by validating s_first_meta_bg first at mount time, and > refusing to mount if its value exceeds the largest possible meta_bg > number. > > Reported-by: Ralf Spenneberg <ralf@xxxxxxx> > Signed-off-by: Eryu Guan <guaneryu@xxxxxxxxx> Thanks, applied. And yes, I do believe you are right about e2fsck having an off-by-one error. Will fix. - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
