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 5128F1D4EC9; Thu, 1 Aug 2024 00:30:52 +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=1722472252; cv=none; b=klI/hOp8ADNy4TsUy7gXHOMRoRGBFpPo+w9E28w2tuApF+lGTRfERFSuykFYZnQE0hxTK7VutAQi2I0lw7eVqK3rEIESXeCxB5TFSJbLZsGnh8CKbh/Aer+NTRNrtlMGrVVk69taEB94SbE3tSMQfuRwAm5rooMu7WI55dlZRSc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722472252; c=relaxed/simple; bh=xVj/RY1YK9ba+1fx93zIYgA7qPfIsnUqCCfTuW7IxnE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hu6ziRAdtexRM/4+FrayRMj0xWFu99E4XOcxZ7QGndjvJN2EmzdIc2boKGrep/SoZiQzJbDFRCB3CdRy0Jrt96ZDqq8IOgK5wCSfCxgUJb3SXlAkLHT8u6elYGstnuH9HySx2JvQt+V3EQSNJHr5ChaLLQGXUBAskzfjcIoVlGw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ggsp67TP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ggsp67TP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DBD4CC116B1; Thu, 1 Aug 2024 00:30:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722472252; bh=xVj/RY1YK9ba+1fx93zIYgA7qPfIsnUqCCfTuW7IxnE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ggsp67TPim5bzdXev8fE3H/cO9+92LaGQORbgSo26i3TOr1FYFuOqcFoBRUHuvxHw He9sFoESZyBzjJJb1yR4cJ4Fx/tFldYXqx2agb8ovm9g54pAv38AMCoIuU67PfmP4j FYYnLVF1UzV47xU67f45N+J//igJwROck9gZ++LPD9uyX6edyEZldBoLbVyHEQtwDb tPRy9RrHXNSiS6xRnEFMAsT+/308f3yoyRIumk1XsV5kXUCmak3myCFs7tv07QMdkP SwJsaucfn4sfVfEhTTQlx9v5t501ismlQazsI3OrzrECNkyyw41ZsLa/OwCU8qMpHR +b3Y56nRlKbKQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Alexey Dobriyan , Kees Cook , Sasha Levin , viro@zeniv.linux.org.uk, brauner@kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH AUTOSEL 6.1 44/61] ELF: fix kernel.randomize_va_space double read Date: Wed, 31 Jul 2024 20:26:02 -0400 Message-ID: <20240801002803.3935985-44-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240801002803.3935985-1-sashal@kernel.org> References: <20240801002803.3935985-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.1.102 Content-Transfer-Encoding: 8bit From: Alexey Dobriyan [ Upstream commit 2a97388a807b6ab5538aa8f8537b2463c6988bd2 ] ELF loader uses "randomize_va_space" twice. It is sysctl and can change at any moment, so 2 loads could see 2 different values in theory with unpredictable consequences. Issue exactly one load for consistent value across one exec. Signed-off-by: Alexey Dobriyan Link: https://lore.kernel.org/r/3329905c-7eb8-400a-8f0a-d87cff979b5b@p183 Signed-off-by: Kees Cook Signed-off-by: Sasha Levin --- fs/binfmt_elf.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index e6c9c0e084486..89e7e4826efce 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1009,7 +1009,8 @@ static int load_elf_binary(struct linux_binprm *bprm) if (elf_read_implies_exec(*elf_ex, executable_stack)) current->personality |= READ_IMPLIES_EXEC; - if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) + const int snapshot_randomize_va_space = READ_ONCE(randomize_va_space); + if (!(current->personality & ADDR_NO_RANDOMIZE) && snapshot_randomize_va_space) current->flags |= PF_RANDOMIZE; setup_new_exec(bprm); @@ -1301,7 +1302,7 @@ static int load_elf_binary(struct linux_binprm *bprm) mm->end_data = end_data; mm->start_stack = bprm->p; - if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1)) { + if ((current->flags & PF_RANDOMIZE) && (snapshot_randomize_va_space > 1)) { /* * For architectures with ELF randomization, when executing * a loader directly (i.e. no interpreter listed in ELF -- 2.43.0