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From: tip-bot for Aravind Gopalakrishnan <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: torvalds@linux-foundation.org, bp@suse.de, tglx@linutronix.de,
	mingo@kernel.org, bp@alien8.de, peterz@infradead.org,
	hpa@zytor.com, Aravind.Gopalakrishnan@amd.com,
	linux-kernel@vger.kernel.org, tony.luck@intel.com
Subject: [tip:ras/core] x86/ras/mce_amd_inj: Return early on invalid input
Date: Mon, 12 Oct 2015 07:31:03 -0700	[thread overview]
Message-ID: <tip-85c9306d44f757d2fb3b0e3e399080a025315c7f@git.kernel.org> (raw)
In-Reply-To: <1444641762-9437-3-git-send-email-bp@alien8.de>

Commit-ID:  85c9306d44f757d2fb3b0e3e399080a025315c7f
Gitweb:     http://git.kernel.org/tip/85c9306d44f757d2fb3b0e3e399080a025315c7f
Author:     Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
AuthorDate: Mon, 12 Oct 2015 11:22:38 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 12 Oct 2015 16:15:47 +0200

x86/ras/mce_amd_inj: Return early on invalid input

Invalid inputs such as these are currently reported in dmesg as
failing:

  $> echo sweet > flags
  [  122.079139] flags_write: Invalid flags value: et

even though the 'flags' attribute has been updated correctly:

  $> cat flags
  sw

This is because userspace keeps writing the remaining buffer
until it encounters an error.

However, the input as a whole is wrong and we should not be
writing anything to the file. Therefore, correct flags_write()
to return -EINVAL immediately on bad input strings.

Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/1443190851-2172-2-git-send-email-Aravind.Gopalakrishnan@amd.com
Link: http://lkml.kernel.org/r/1444641762-9437-3-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/ras/mce_amd_inj.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/x86/ras/mce_amd_inj.c b/arch/x86/ras/mce_amd_inj.c
index 17e35b5..4fd8bb9 100644
--- a/arch/x86/ras/mce_amd_inj.c
+++ b/arch/x86/ras/mce_amd_inj.c
@@ -129,12 +129,9 @@ static ssize_t flags_write(struct file *filp, const char __user *ubuf,
 {
 	char buf[MAX_FLAG_OPT_SIZE], *__buf;
 	int err;
-	size_t ret;
 
 	if (cnt > MAX_FLAG_OPT_SIZE)
-		cnt = MAX_FLAG_OPT_SIZE;
-
-	ret = cnt;
+		return -EINVAL;
 
 	if (copy_from_user(&buf, ubuf, cnt))
 		return -EFAULT;
@@ -150,9 +147,9 @@ static ssize_t flags_write(struct file *filp, const char __user *ubuf,
 		return err;
 	}
 
-	*ppos += ret;
+	*ppos += cnt;
 
-	return ret;
+	return cnt;
 }
 
 static const struct file_operations flags_fops = {

  reply	other threads:[~2015-10-12 14:35 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-12  9:22 [PATCH 0/6] tip-queue 2015-10-12 Borislav Petkov
2015-10-12  9:22 ` [PATCH 1/6] x86/mce: Don't clear shared banks on Intel when offlining CPUs Borislav Petkov
2015-10-12  9:22 ` [PATCH 2/6] x86/ras/mce_amd_inj: Return early on invalid input Borislav Petkov
2015-10-12 14:31   ` tip-bot for Aravind Gopalakrishnan [this message]
2015-10-12  9:22 ` [PATCH 3/6] x86/ras/mce_amd_inj: Trigger deferred and thresholding errors interrupts Borislav Petkov
2015-10-12 14:31   ` [tip:ras/core] " tip-bot for Aravind Gopalakrishnan
2015-10-12  9:22 ` [PATCH 4/6] x86/ras/mce_amd_inj: Inject bank 4 errors on the NBC Borislav Petkov
2015-10-12 14:31   ` [tip:ras/core] " tip-bot for Aravind Gopalakrishnan
2015-10-12  9:22 ` [PATCH 5/6] x86/microcode/amd: Extract current patch level read to a function Borislav Petkov
2015-10-12 14:32   ` [tip:ras/core] " tip-bot for Borislav Petkov
2015-10-12  9:22 ` [PATCH 6/6] x86/microcode/amd: Do not overwrite final patch levels Borislav Petkov
2015-10-12 14:32   ` [tip:ras/core] " tip-bot for Borislav Petkov
  -- strict thread matches above, loose matches on Subject: below --
2015-09-25 14:20 [PATCH V2 0/3] Updates to mce_amd_inj module Aravind Gopalakrishnan
2015-09-25 14:20 ` [PATCH V2 1/3] RAS, mce_amd_inj: Return early on invalid input Aravind Gopalakrishnan
2015-09-25 14:20 ` [PATCH V2 2/3] RAS, mce_amd_inj: Add capability to trigger apic interrupts Aravind Gopalakrishnan
2015-09-25 14:20 ` [PATCH V2 3/3] RAS, mce_amd_inj: Inject errors on NBC for bank 4 errors Aravind Gopalakrishnan
2015-09-28  9:06 ` [PATCH V2 0/3] Updates to mce_amd_inj module Borislav Petkov

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