From 6360ab278cc1ac3e1235e0755e4cba1f918e6f3c Mon Sep 17 00:00:00 2001 From: Peter Lieven Date: Fri, 13 Jul 2018 09:15:39 +0200 Subject: [PATCH] qemu-img: avoid overflow of min_sparse parameter the min_sparse convert parameter can overflow (e.g. -S 1024G) in the conversion from int64_t to int resulting in a negative min_sparse parameter. Avoid this by limiting the valid parameters to sane values. In fact anything exceeding the convert buffer size is also pointless. While at it also forbid values that are non multiple of 512 to avoid undesired behaviour. For instance, values between 1 and 511 were legal, but resulted in full allocation. Cc: qemu-stable@nongnu.org Signed-off-by: Peter Lieven Signed-off-by: Kevin Wolf --- qemu-img.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/qemu-img.c b/qemu-img.c index 4a7ce43dc9..9b7506b8ae 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -2005,6 +2005,8 @@ static int convert_do_copy(ImgConvertState *s) return s->ret; } +#define MAX_BUF_SECTORS 32768 + static int img_convert(int argc, char **argv) { int c, bs_i, flags, src_flags = 0; @@ -2100,8 +2102,12 @@ static int img_convert(int argc, char **argv) int64_t sval; sval = cvtnum(optarg); - if (sval < 0) { - error_report("Invalid minimum zero buffer size for sparse output specified"); + if (sval < 0 || sval & (BDRV_SECTOR_SIZE - 1) || + sval / BDRV_SECTOR_SIZE > MAX_BUF_SECTORS) { + error_report("Invalid buffer size for sparse output specified. " + "Valid sizes are multiples of %llu up to %llu. Select " + "0 to disable sparse detection (fully allocates output).", + BDRV_SECTOR_SIZE, MAX_BUF_SECTORS * BDRV_SECTOR_SIZE); goto fail_getopt; } @@ -2385,9 +2391,9 @@ static int img_convert(int argc, char **argv) } /* increase bufsectors from the default 4096 (2M) if opt_transfer - * or discard_alignment of the out_bs is greater. Limit to 32768 (16MB) - * as maximum. */ - s.buf_sectors = MIN(32768, + * or discard_alignment of the out_bs is greater. Limit to + * MAX_BUF_SECTORS as maximum which is currently 32768 (16MB). */ + s.buf_sectors = MIN(MAX_BUF_SECTORS, MAX(s.buf_sectors, MAX(out_bs->bl.opt_transfer >> BDRV_SECTOR_BITS, out_bs->bl.pdiscard_alignment >>