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From: Al Viro <viro@ZenIV.linux.org.uk>
To: linux-kernel@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	linux-fsdevel@vger.kernel.org,
	Tom Lendacky <thomas.lendacky@amd.com>
Subject: [PATCH 13/20] drivers/crypto/ccp/sev-dev.c: get rid of pointless access_ok()
Date: Sun, 10 May 2020 00:45:50 +0100	[thread overview]
Message-ID: <20200509234557.1124086-13-viro@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20200509234557.1124086-1-viro@ZenIV.linux.org.uk>

From: Al Viro <viro@zeniv.linux.org.uk>

Contrary to the comments, those do *NOT* verify anything about
writability of memory, etc.

In all cases addresses are passed only to copy_to_user().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 drivers/crypto/ccp/sev-dev.c | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 896f190b9a50..7f97164cbafb 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -371,8 +371,7 @@ static int sev_ioctl_do_pek_csr(struct sev_issue_cmd *argp, bool writable)
 		goto cmd;
 
 	/* allocate a physically contiguous buffer to store the CSR blob */
-	if (!access_ok(input.address, input.length) ||
-	    input.length > SEV_FW_BLOB_MAX_SIZE) {
+	if (input.length > SEV_FW_BLOB_MAX_SIZE) {
 		ret = -EFAULT;
 		goto e_free;
 	}
@@ -609,12 +608,6 @@ static int sev_ioctl_do_get_id2(struct sev_issue_cmd *argp)
 	if (copy_from_user(&input, (void __user *)argp->data, sizeof(input)))
 		return -EFAULT;
 
-	/* Check if we have write access to the userspace buffer */
-	if (input.address &&
-	    input.length &&
-	    !access_ok(input.address, input.length))
-		return -EFAULT;
-
 	data = kzalloc(sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
@@ -730,15 +723,13 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp, bool writable)
 		goto cmd;
 
 	/* Allocate a physically contiguous buffer to store the PDH blob. */
-	if ((input.pdh_cert_len > SEV_FW_BLOB_MAX_SIZE) ||
-	    !access_ok(input.pdh_cert_address, input.pdh_cert_len)) {
+	if (input.pdh_cert_len > SEV_FW_BLOB_MAX_SIZE) {
 		ret = -EFAULT;
 		goto e_free;
 	}
 
 	/* Allocate a physically contiguous buffer to store the cert chain blob. */
-	if ((input.cert_chain_len > SEV_FW_BLOB_MAX_SIZE) ||
-	    !access_ok(input.cert_chain_address, input.cert_chain_len)) {
+	if (input.cert_chain_len > SEV_FW_BLOB_MAX_SIZE) {
 		ret = -EFAULT;
 		goto e_free;
 	}
-- 
2.11.0


  parent reply	other threads:[~2020-05-09 23:46 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-09 23:41 [PATCHES] uaccess simple access_ok() removals Al Viro
2020-05-09 23:45 ` [PATCH 01/20] dlmfs_file_write(): get rid of pointless access_ok() Al Viro
2020-05-09 23:45   ` [PATCH 02/20] fat_dir_ioctl(): hadn't needed that access_ok() for more than a decade Al Viro
2020-05-09 23:45   ` [PATCH 03/20] btrfs_ioctl_send(): don't bother with access_ok() Al Viro
2020-05-09 23:45   ` [PATCH 04/20] FIEMAP: " Al Viro
2020-05-10  7:02     ` Christoph Hellwig
2020-05-13 19:02       ` Al Viro
2020-05-13 19:38         ` Christoph Hellwig
2020-05-29 15:01           ` Al Viro
2020-05-09 23:45   ` [PATCH 05/20] tomoyo_write_control(): get rid of pointless access_ok() Al Viro
2020-05-10  0:50     ` Tetsuo Handa
2020-05-10  0:57       ` Linus Torvalds
2020-05-10  1:04         ` Tetsuo Handa
2020-05-10  3:01         ` Al Viro
2020-05-09 23:45   ` [PATCH 06/20] n_hdlc_tty_read(): remove " Al Viro
2020-05-15 10:53     ` Greg Kroah-Hartman
2020-05-09 23:45   ` [PATCH 07/20] nvram: drop useless access_ok() Al Viro
2020-05-15 10:54     ` Greg Kroah-Hartman
2020-05-09 23:45   ` [PATCH 08/20] cm4000_cs.c cmm_ioctl(): get rid of pointless access_ok() Al Viro
2020-05-09 23:45   ` [PATCH 09/20] drivers/fpga/dfl-fme-pr.c: " Al Viro
2020-05-09 23:45   ` [PATCH 10/20] drivers/fpga/dfl-afu-dma-region.c: " Al Viro
2020-05-09 23:45   ` [PATCH 11/20] amifb: get rid of pointless access_ok() calls Al Viro
2020-05-14 13:45     ` Bartlomiej Zolnierkiewicz
2020-05-14 14:07       ` Al Viro
2020-05-14 14:25         ` Bartlomiej Zolnierkiewicz
2020-05-14 17:41           ` Al Viro
2020-05-14 20:21             ` Geert Uytterhoeven
2020-05-09 23:45   ` [PATCH 12/20] omapfb: " Al Viro
2020-05-14 13:39     ` Bartlomiej Zolnierkiewicz
2020-05-09 23:45   ` Al Viro [this message]
2020-05-09 23:45   ` [PATCH 14/20] via-pmu: don't bother with access_ok() Al Viro
2020-05-09 23:45   ` [PATCH 15/20] drm_read(): get rid of pointless access_ok() Al Viro
2020-05-09 23:45   ` [PATCH 16/20] efi_test: " Al Viro
2020-05-09 23:45   ` [PATCH 17/20] lpfc_debugfs: " Al Viro
2020-05-09 23:45   ` [PATCH 18/20] usb: get rid of pointless access_ok() calls Al Viro
2020-05-15 10:53     ` Greg Kroah-Hartman
2020-05-09 23:45   ` [PATCH 19/20] hfi1: get rid of pointless access_ok() Al Viro
2020-05-09 23:45   ` [PATCH 4/4] vmci_host: " Al Viro
2020-05-15 10:53     ` Greg Kroah-Hartman
2020-05-10  0:34 ` [PATCHES] uaccess simple access_ok() removals Linus Torvalds
2020-05-10  3:27   ` Al Viro
2020-05-10 14:34 ` David Laight

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