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Wysocki" , Len Brown , Corey Minyard , Gabriel Somlo , "Michael S. Tsirkin" , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , David Airlie , Simona Vetter , Bart Van Assche , Jason Gunthorpe , Leon Romanovsky , Laurent Pinchart , Hans de Goede , Mauro Carvalho Chehab , Bjorn Helgaas , Hannes Reinecke , "James E.J. Bottomley" , "Martin K. Petersen" , Daniel Lezcano , Zhang Rui , Lukasz Luba , Greg Kroah-Hartman , Jiri Slaby , Alan Stern , Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Jason Baron , Jim Cromie , Tiwei Bie , Benjamin Berg , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , "David E. Box" , "Maciej W. Rozycki" , Srinivas Pandruvada , Peter Zijlstra , Heiko Carstens , Vasily Gorbik , Sean Christopherson , Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Vinod Koul , Frank Li , Daniel Gomez , Sami Tolvanen , Aaron Tomlin , Alexander Potapenko , Marco Elver , Dmitry Vyukov , Andrew Morton , John Johansen , Paul Moore , James Morris , "Serge E. Hallyn" , Andy Shevchenko , Georgia Garcia , kvm@vger.kernel.org, dmaengine@vger.kernel.org, linux-modules@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, apparmor@lists.ubuntu.com, linux-security-module@vger.kernel.org, linux-um@lists.infradead.org, linux-acpi@vger.kernel.org, openipmi-developer@lists.sourceforge.net, qemu-devel@nongnu.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, linux-pci@vger.kernel.org, linux-scsi@vger.kernel.org, linux-pm@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-serial@vger.kernel.org, linux-usb@vger.kernel.org, usb-storage@lists.one-eyed-alien.net, virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, netdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH 01/11] params: bound array element output to the caller's page buffer Date: Thu, 21 May 2026 06:33:14 -0700 Message-Id: <20260521133326.2465264-1-kees@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260521133315.work.845-kees@kernel.org> References: <20260521133315.work.845-kees@kernel.org> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2143; i=kees@kernel.org; h=from:subject; bh=3eO38ZdE0rbljlF5l/QfEOapKDQ3GxlJmKbxHXugskI=; b=owGbwMvMwCVmps19z/KJym7G02pJDFn8nAtqmS7cf3B//69jZ5rrq6va9p3fNOGM7h2Jd74Pn JTCV6u3dZSyMIhxMciKKbIE2bnHuXi8bQ93n6sIM4eVCWQIAxenAEzEYiojw//ne8uu9YZ9+sWp mJ7czDyrP2Afv+2f21+/99yL9Jp+OI2RYVNeQ9witS6BzPe55aerW/eveRmS81ixc8XMVftPpj7 OZQAA X-Developer-Key: i=kees@kernel.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Content-Transfer-Encoding: 8bit From: Pengpeng Hou param_array_get() appends each element's string representation into the shared sysfs page buffer by passing buffer + off to the element getter. That works for getters that only write a small bounded string, but param_get_charp() and similar helpers format against PAGE_SIZE from the pointer they receive. Once off is non-zero, an element getter can therefore write past the end of the original sysfs page buffer. Collect each element into a temporary PAGE_SIZE buffer first and then copy only the remaining space into the caller's page buffer. Cc: stable@vger.kernel.org Reviewed-by: Petr Pavlu Signed-off-by: Pengpeng Hou Signed-off-by: Kees Cook --- kernel/params.c | 26 ++++++++++++++++++++------ 1 file changed, 20 insertions(+), 6 deletions(-) diff --git a/kernel/params.c b/kernel/params.c index 74d620bc2521..752721922a15 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -475,22 +475,36 @@ static int param_array_set(const char *val, const struct kernel_param *kp) static int param_array_get(char *buffer, const struct kernel_param *kp) { int i, off, ret; + char *elem_buf; const struct kparam_array *arr = kp->arr; struct kernel_param p = *kp; + elem_buf = kmalloc(PAGE_SIZE, GFP_KERNEL); + if (!elem_buf) + return -ENOMEM; + for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) { - /* Replace \n with comma */ - if (i) - buffer[off - 1] = ','; p.arg = arr->elem + arr->elemsize * i; check_kparam_locked(p.mod); - ret = arr->ops->get(buffer + off, &p); + ret = arr->ops->get(elem_buf, &p); if (ret < 0) - return ret; + goto out; + ret = min(ret, (int)(PAGE_SIZE - 1 - off)); + if (!ret) + break; + /* Replace the previous element's trailing newline with a comma. */ + if (i) + buffer[off - 1] = ','; + memcpy(buffer + off, elem_buf, ret); off += ret; + if (off == PAGE_SIZE - 1) + break; } buffer[off] = '\0'; - return off; + ret = off; +out: + kfree(elem_buf); + return ret; } static void param_array_free(void *arg) -- 2.34.1