From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0AE0542982D; Tue, 12 May 2026 17:46:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778608001; cv=none; b=tBFiXfgyAXwO1g/7RMvyFP9zlpVxEcG4k8ueF5BEvf8XG0cB1zUNltQ0k8O7uP2L514HKfKBVOa672aNStTVf4iwH8twU+PWXMHoINcofAZz/B4ElvG21BtdSf6L3rK3Sb5Cksf3p8kcGW28E65dIQq8KIZyV5FYIVtxEOSaE0c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778608001; c=relaxed/simple; bh=+oh8owfe8Zh1mXSPy0vGwlCEbNo2SDe+4aIjdWWIIv4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hjMFrD/w6zlQTEMve69JcnI+H0QHNojsU+JaNimxCjcybH3aHDXr3UGylkYN0sh98vh3A3gX88ZYfbwYAGScHS0VJx4BnLSvcagdiOzR2yy7kpLIBps3K4TJCuIZt0iH110WKtZq+5/Pw3tnAQ3zWHPz+jwGxgadU0FVdBLHDCo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=z9aXKffA; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="z9aXKffA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95E2BC2BCB0; Tue, 12 May 2026 17:46:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778608000; bh=+oh8owfe8Zh1mXSPy0vGwlCEbNo2SDe+4aIjdWWIIv4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=z9aXKffAxOkc/kP7vfTIxD8mS7JThBj9xNw8yBns1shARc/kQ2i3VubmkvDn51RFT sG8zqI/XPaSGBA6OXs9eYkk+L6yFQn0f5hRMiSGoVLH954UMNaA/yhjytd2SJIoT6L Wgg5pQf2pK3K17y16jEo3hnYGGcgeCaPfMHsLUNw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Biggers , Mikulas Patocka Subject: [PATCH 6.12 119/206] dm-verity-fec: correctly reject too-small FEC devices Date: Tue, 12 May 2026 19:39:31 +0200 Message-ID: <20260512173935.376209539@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260512173932.810559588@linuxfoundation.org> References: <20260512173932.810559588@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Biggers commit 2b14e0bb63cc671120e7791658f5c494fc66d072 upstream. Fix verity_fec_ctr() to reject too-small FEC devices by correctly computing the number of parity blocks as 'f->rounds * f->roots'. Previously it incorrectly used 'div64_u64(f->rounds * f->roots, v->fec->roots << SECTOR_SHIFT)' which is a much smaller value. Note that the units of 'rounds' are blocks, not bytes. This matches the units of the value returned by dm_bufio_get_device_size(), which are also blocks. A later commit will give 'rounds' a clearer name. Fixes: a739ff3f543a ("dm verity: add support for forward error correction") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Signed-off-by: Mikulas Patocka Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-verity-fec.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/drivers/md/dm-verity-fec.c +++ b/drivers/md/dm-verity-fec.c @@ -668,7 +668,7 @@ int verity_fec_ctr(struct dm_verity *v) { struct dm_verity_fec *f = v->fec; struct dm_target *ti = v->ti; - u64 hash_blocks, fec_blocks; + u64 hash_blocks; int ret; if (!verity_fec_is_enabled(v)) { @@ -749,8 +749,7 @@ int verity_fec_ctr(struct dm_verity *v) dm_bufio_set_sector_offset(f->bufio, f->start << (v->data_dev_block_bits - SECTOR_SHIFT)); - fec_blocks = div64_u64(f->rounds * f->roots, v->fec->roots << SECTOR_SHIFT); - if (dm_bufio_get_device_size(f->bufio) < fec_blocks) { + if (dm_bufio_get_device_size(f->bufio) < f->rounds * f->roots) { ti->error = "FEC device is too small"; return -E2BIG; }