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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-490b61511c4sm51593825e9.1.2026.06.03.02.17.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 03 Jun 2026 02:17:28 -0700 (PDT) Date: Wed, 3 Jun 2026 10:17:26 +0100 From: David Laight To: "David Hildenbrand (Arm)" Cc: Aiden Bowling , Lorenzo Stoakes , Andrew Morton , Vlastimil Babka , linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] kernel/sys.c: fix prctl_set_auxv to use sizeof instead of user-supplied len Message-ID: <20260603101726.05d1f7a8@pumpkin> In-Reply-To: References: <20260602024001.14119-2-aidenlbowling56@gmail.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Tue, 2 Jun 2026 19:25:56 +0200 "David Hildenbrand (Arm)" wrote: > On 6/2/26 16:14, Aiden Bowling wrote: > > The issue is that using the user-supplied 'len' risks a partial write into mm- > >>saved_auxv if they pass something smaller than the actual buffer size, even if > > the buffer is validated. We should always copy the full buffer size after > > validation to maintain consistency and prevent accidental partial data exposure/ > > corruption. > > Which partial data exposure? > The one you don't get with the patch because of the previously unnecessary initialisation of the array :-)