From 58607752d173438994d28dea7e2c2587726663e6 Mon Sep 17 00:00:00 2001 From: Denis Rastyogin Date: Thu, 12 Dec 2024 13:41:22 +0300 Subject: [PATCH] parallels: fix ext_off assertion failure due to overflow This error was discovered by fuzzing qemu-img. When ph.ext_off has a sufficiently large value, the operation le64_to_cpu(ph.ext_off) << BDRV_SECTOR_BITS in parallels_read_format_extension() can cause an overflow in int64_t. This overflow triggers the assert(ext_off > 0) check in block/parallels-ext.c: parallels_read_format_extension(), leading to a crash. This commit adds a check to prevent overflow when shifting ph.ext_off by BDRV_SECTOR_BITS, ensuring that the value remains within a valid range. Reported-by: Leonid Reviakin Signed-off-by: Denis Rastyogin Reviewed-by: Denis V. Lunev Message-ID: <20241212104212.513947-2-gerben@altlinux.org> Signed-off-by: Stefan Hajnoczi --- block/parallels.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/block/parallels.c b/block/parallels.c index 23751b28a9..d4bfc44e64 100644 --- a/block/parallels.c +++ b/block/parallels.c @@ -1298,6 +1298,10 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags, error_setg(errp, "Catalog too large"); return -EFBIG; } + if (le64_to_cpu(ph.ext_off) >= (INT64_MAX >> BDRV_SECTOR_BITS)) { + error_setg(errp, "Invalid image: Too big offset"); + return -EFBIG; + } size = bat_entry_off(s->bat_size); s->header_size = ROUND_UP(size, bdrv_opt_mem_align(bs->file->bs)); -- 2.49.0