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b=IryUmZ+mXF4GfyQdAHopS4/cmmA+xngA6VRRg1SncpJsF4RmFhXXRSDGRoorqw4za hA0/IfoJk/XxY2olUVGCV5msq6vk+3GWfXNhgqXliqRzF6viIfKlZgKZLwDOatUOK1 CH+67oBvFyksjumqvQu6BF+4uu8Lvofiwui5pUMRL6I0BDTHUlNctW+AuroRFsXijf PnOn8EkXIenlS1OnkJ5N+QDQazWOaXqS9oqt6WM0Tt9DzXXknaGYH6QnLbdyO/U81Y 31ruFNPBrRImfzVwt59jh1ZNtfaWcTvcXEPSUYZ7BiGDXcML6K59FFj6iyusVWBdAU JFeTt9TgQMoJA== 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 5.15 34/47] ELF: fix kernel.randomize_va_space double read Date: Wed, 31 Jul 2024 20:31:24 -0400 Message-ID: <20240801003256.3937416-34-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240801003256.3937416-1-sashal@kernel.org> References: <20240801003256.3937416-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.15.164 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 0404F1C0004 X-Stat-Signature: sq7yrbiu4p1xnfuwwpxy8i475uzipaa9 X-Rspam-User: X-HE-Tag: 1722472514-109180 X-HE-Meta: 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 EUvDGtJA GCjynj7nzZbD4N4v7wCqKqYBZ3WdNZCl//KjSqhL8kGmKoHwBcJ8mEmig0aRh3msghFH14h9zLaOvrpEG9Z8ECqisclsL2gnrT4G88J7qRzJNTRvx+G9LN0vLDcXWxdLY1N8z5e8sj0uiYazc8OLBSK5hqPBgXHjN4+pLusVhOJq7wRyw0ziu2M0pDenPLcYq1VZs0uA8tSDl0Rx9vpndrPaOI9VET65DipsjNQ2wIdQA/QGnBnbvGYYVwAQrmN/aO8d49Ly1yg+QglivVtytvFv4Ph10gPydC+by5Pcww5VWHo8= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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 30379c33ad20c..4a11784b9f896 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1008,7 +1008,8 @@ 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); @@ -1278,7 +1279,7 @@ 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