April 2025 - Linux-stable-mirror

by Hamza Mahfooz

Hi, Please include commit ec4696925da6 ("efi/libstub: Bump up EFI_MMAP_NR_SLACK_SLOTS to 32") in kernel 6.6+, it allows us to be able to boot some arm64 efi machines without any workarounds. Thanks, Hamza

4 months, 1 week

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[PATCH] Revert "PCI: Avoid reset when disabled via sysfs"

by Alex Williamson

This reverts commit 479380efe1625e251008d24b2810283db60d6fcd. The reset_method attribute on a PCI device is only intended to manage the availability of function scoped resets for a device. It was never intended to restrict resets targeting the bus or slot. In introducing a restriction that each device must support function level reset by testing pci_reset_supported(), we essentially create a catch-22, that a device must have a function scope reset in order to support bus/slot reset, when we use bus/slot reset to effect a reset of a device that does not support a function scoped reset, especially multi-function devices. This breaks the majority of uses cases where vfio-pci uses bus/slot resets to manage multifunction devices that do not support function scoped resets. Fixes: 479380efe162 ("PCI: Avoid reset when disabled via sysfs") Reported-by: Cal Peake <cp(a)absolutedigital.net> Link: https://lore.kernel.org/all/808e1111-27b7-f35b-6d5c-5b275e73677b@absolutedi… Cc: stable(a)vger.kernel.org Signed-off-by: Alex Williamson <alex.williamson(a)redhat.com> --- drivers/pci/pci.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 4d7c9f64ea24..e77d5b53c0ce 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5429,8 +5429,6 @@ static bool pci_bus_resettable(struct pci_bus *bus) return false; list_for_each_entry(dev, &bus->devices, bus_list) { - if (!pci_reset_supported(dev)) - return false; if (dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET || (dev->subordinate && !pci_bus_resettable(dev->subordinate))) return false; @@ -5507,8 +5505,6 @@ static bool pci_slot_resettable(struct pci_slot *slot) list_for_each_entry(dev, &slot->bus->devices, bus_list) { if (!dev->slot || dev->slot != slot) continue; - if (!pci_reset_supported(dev)) - return false; if (dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET || (dev->subordinate && !pci_bus_resettable(dev->subordinate))) return false; -- 2.48.1

4 months, 1 week

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[PATCH] Bluetooth: vhci: Avoid needless snprintf() calls

by Kees Cook

Avoid double-copying of string literals. Use a "const char *" for each string instead of copying from .rodata into stack and then into the skb. We can go directly from .rodata to the skb. This also works around a Clang bug (that has since been fixed[1]). Reported-by: kernel test robot <lkp(a)intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202401250927.1poZERd6-lkp@intel.com/ Fixes: ab4e4380d4e1 ("Bluetooth: Add vhci devcoredump support") Link: https://github.com/llvm/llvm-project/commit/ea2e66aa8b6e363b89df66dc44275a0… [1] Cc: stable(a)vger.kernel.org Signed-off-by: Kees Cook <kees(a)kernel.org> --- Cc: Marcel Holtmann <marcel(a)holtmann.org> Cc: Luiz Augusto von Dentz <luiz.dentz(a)gmail.com> Cc: Josh Poimboeuf <jpoimboe(a)kernel.org> Cc: Nathan Chancellor <nathan(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: linux-bluetooth(a)vger.kernel.org --- drivers/bluetooth/hci_vhci.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/bluetooth/hci_vhci.c b/drivers/bluetooth/hci_vhci.c index 7651321d351c..9ac22e4a070b 100644 --- a/drivers/bluetooth/hci_vhci.c +++ b/drivers/bluetooth/hci_vhci.c @@ -289,18 +289,18 @@ static void vhci_coredump(struct hci_dev *hdev) static void vhci_coredump_hdr(struct hci_dev *hdev, struct sk_buff *skb) { - char buf[80]; + const char *buf; - snprintf(buf, sizeof(buf), "Controller Name: vhci_ctrl\n"); + buf = "Controller Name: vhci_ctrl\n"; skb_put_data(skb, buf, strlen(buf)); - snprintf(buf, sizeof(buf), "Firmware Version: vhci_fw\n"); + buf = "Firmware Version: vhci_fw\n"; skb_put_data(skb, buf, strlen(buf)); - snprintf(buf, sizeof(buf), "Driver: vhci_drv\n"); + buf = "Driver: vhci_drv\n"; skb_put_data(skb, buf, strlen(buf)); - snprintf(buf, sizeof(buf), "Vendor: vhci\n"); + buf = "Vendor: vhci\n"; skb_put_data(skb, buf, strlen(buf)); } -- 2.34.1

4 months, 1 week

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[PATCH v3] loop: LOOP_SET_FD: send uevents for partitions

by Thomas Weißschuh

Remove the suppression of the uevents before scanning for partitions. The partitions inherit their suppression settings from their parent device, which lead to the uevents being dropped. This is similar to the same changes for LOOP_CONFIGURE done in commit bb430b694226 ("loop: LOOP_CONFIGURE: send uevents for partitions"). Fixes: 498ef5c777d9 ("loop: suppress uevents while reconfiguring the device") Cc: stable(a)vger.kernel.org Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de> --- Changes in v3: - Rebase onto block/block-6.15 - Drop already applied patch "loop: properly send KOBJ_CHANGED uevent for disk device" - Add patch to fix partition uevents for LOOP_SET_FD - Link to v2: https://lore.kernel.org/r/20250415-loop-uevent-changed-v2-1-0c4e6a923b2a@li… Changes in v2: - Use correct Fixes tag - Rework commit message slightly - Rebase onto v6.15-rc1 - Link to v1: https://lore.kernel.org/r/20250317-loop-uevent-changed-v1-1-cb29cb91b62d@li… --- drivers/block/loop.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 3be7f00e7fc740da2745ffbccfcebe53eef2ddaa..e9ec7a45f3f2d1dd2a82b3506f3740089a20ae05 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -662,12 +662,12 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, * dependency. */ fput(old_file); + dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 0); if (partscan) loop_reread_partitions(lo); error = 0; done: - dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 0); kobject_uevent(&disk_to_dev(lo->lo_disk)->kobj, KOBJ_CHANGE); return error; @@ -675,6 +675,7 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, loop_global_unlock(lo, is_loop); out_putf: fput(file); + dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 0); goto done; } --- base-commit: 7ed2a771b5fb3edee9c4608181235c30b40bb042 change-id: 20250307-loop-uevent-changed-aa3690f43e03 Best regards, -- Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>

4 months, 1 week

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Re: [regression 6.1.y] Regression from 476c1dfefab8 ("mm: Don't pin ZERO_PAGE in pin_user_pages()") with pci-passthrough for both KVM VMs and booting in xen DomU

by Salvatore Bonaccorso

[resent with correct stable(a)vger.kernel.org list] On Tue, Apr 15, 2025 at 08:59:19PM +0200, Salvatore Bonaccorso wrote: > Hi > > [Apologies if this has been reported already but I have not found an > already filled corresponding report] > > After updating from the 6.1.129 based version to 6.1.133, various > users have reported that their VMs do not boot anymore up (both KVM > and under Xen) if pci-passthrough is involved. The reports are at: > > https://bugs.debian.org/1102889 > https://bugs.debian.org/1102914 > https://bugs.debian.org/1103153 > > Milan Broz bisected the issues and found that the commit introducing > the problems can be tracked down to backport of c8070b787519 ("mm: > Don't pin ZERO_PAGE in pin_user_pages()") from 6.5-rc1 which got > backported as 476c1dfefab8 ("mm: Don't pin ZERO_PAGE in > pin_user_pages()") in 6.1.130. See https://bugs.debian.org/1102914#60 > > #regzbot introduced: 476c1dfefab8b98ae9c3e3ad283c2ac10d30c774 > > 476c1dfefab8b98ae9c3e3ad283c2ac10d30c774 is the first bad commit > commit 476c1dfefab8b98ae9c3e3ad283c2ac10d30c774 > Author: David Howells <dhowells(a)redhat.com> > Date: Fri May 26 22:41:40 2023 +0100 > > mm: Don't pin ZERO_PAGE in pin_user_pages() > > [ Upstream commit c8070b78751955e59b42457b974bea4a4fe00187 ] > > Make pin_user_pages*() leave a ZERO_PAGE unpinned if it extracts a pointer > to it from the page tables and make unpin_user_page*() correspondingly > ignore a ZERO_PAGE when unpinning. We don't want to risk overrunning a > zero page's refcount as we're only allowed ~2 million pins on it - > something that userspace can conceivably trigger. > > Add a pair of functions to test whether a page or a folio is a ZERO_PAGE. > > Signed-off-by: David Howells <dhowells(a)redhat.com> > cc: Christoph Hellwig <hch(a)infradead.org> > cc: David Hildenbrand <david(a)redhat.com> > cc: Lorenzo Stoakes <lstoakes(a)gmail.com> > cc: Andrew Morton <akpm(a)linux-foundation.org> > cc: Jens Axboe <axboe(a)kernel.dk> > cc: Al Viro <viro(a)zeniv.linux.org.uk> > cc: Matthew Wilcox <willy(a)infradead.org> > cc: Jan Kara <jack(a)suse.cz> > cc: Jeff Layton <jlayton(a)kernel.org> > cc: Jason Gunthorpe <jgg(a)nvidia.com> > cc: Logan Gunthorpe <logang(a)deltatee.com> > cc: Hillf Danton <hdanton(a)sina.com> > cc: Christian Brauner <brauner(a)kernel.org> > cc: Linus Torvalds <torvalds(a)linux-foundation.org> > cc: linux-fsdevel(a)vger.kernel.org > cc: linux-block(a)vger.kernel.org > cc: linux-kernel(a)vger.kernel.org > cc: linux-mm(a)kvack.org > Reviewed-by: Lorenzo Stoakes <lstoakes(a)gmail.com> > Reviewed-by: Christoph Hellwig <hch(a)lst.de> > Acked-by: David Hildenbrand <david(a)redhat.com> > Link: https://lore.kernel.org/r/20230526214142.958751-2-dhowells@redhat.com > Signed-off-by: Jens Axboe <axboe(a)kernel.dk> > Stable-dep-of: bddf10d26e6e ("uprobes: Reject the shared zeropage in uprobe_write_opcode()") > Signed-off-by: Sasha Levin <sashal(a)kernel.org> > > Documentation/core-api/pin_user_pages.rst | 6 ++++++ > include/linux/mm.h | 26 ++++++++++++++++++++++++-- > mm/gup.c | 31 ++++++++++++++++++++++++++++++- > 3 files changed, 60 insertions(+), 3 deletions(-) > > Milan verified that the issue persists in 6.1.134 so far and the patch > itself cannot be just reverted. > > The failures all have a similar pattern, when pci-passthrough is used > for a pci devide, for instance under qemu the bootup will fail with: > > qemu-system-x86_64: -device {"driver":"vfio-pci","host":"0000:03:00.0","id":"hostdev0","bus":"pci.3","addr":"0x0"}: VFIO_MAP_DMA failed: Cannot allocate memory > qemu-system-x86_64: -device {"driver":"vfio-pci","host":"0000:03:00.0","id":"hostdev0","bus":"pci.3","addr":"0x0"}: vfio 0000:03:00.0: failed to setup container > > (in the case as reported by Milan). > > Any ideas here? > > Regards, > Salvatore

4 months, 1 week

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[PATCH] rust: kbuild: use `pound` to support GNU Make < 4.3

by Miguel Ojeda

GNU Make 4.3 changed the behavior of `#` inside commands in commit c6966b323811 ("[SV 20513] Un-escaped # are not comments in function invocations"): * WARNING: Backward-incompatibility! Number signs (#) appearing inside a macro reference or function invocation no longer introduce comments and should not be escaped with backslashes: thus a call such as: foo := $(shell echo '#') is legal. Previously the number sign needed to be escaped, for example: foo := $(shell echo '\#') Now this latter will resolve to "\#". If you want to write makefiles portable to both versions, assign the number sign to a variable: H := \# foo := $(shell echo '$H') This was claimed to be fixed in 3.81, but wasn't, for some reason. To detect this change search for 'nocomment' in the .FEATURES variable. Unlike other commits in the kernel about this issue, such as commit 633174a7046e ("lib/raid6/test/Makefile: Use $(pound) instead of \# for Make 4.3"), that fixed the issue for newer GNU Makes, in our case it was the opposite, i.e. we need to fix it for the older ones: someone building with e.g. 4.2.1 gets the following error: scripts/Makefile.compiler:81: *** unterminated call to function 'call': missing ')'. Stop. Thus use the existing variable to fix it. Reported-by: moyi geek Closes: https://rust-for-linux.zulipchat.com/#narrow/channel/291565/topic/x/near/51… Cc: stable(a)vger.kernel.org Fixes: e72a076c620f ("kbuild: fix issues with rustc-option") Signed-off-by: Miguel Ojeda <ojeda(a)kernel.org> --- scripts/Makefile.compiler | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/scripts/Makefile.compiler b/scripts/Makefile.compiler index 7ed7f92a7daa..f4fcc1eaaeae 100644 --- a/scripts/Makefile.compiler +++ b/scripts/Makefile.compiler @@ -79,7 +79,7 @@ ld-option = $(call try-run, $(LD) $(KBUILD_LDFLAGS) $(1) -v,$(1),$(2),$(3)) # Usage: MY_RUSTFLAGS += $(call __rustc-option,$(RUSTC),$(MY_RUSTFLAGS),-Cinstrument-coverage,-Zinstrument-coverage) # TODO: remove RUSTC_BOOTSTRAP=1 when we raise the minimum GNU Make version to 4.4 __rustc-option = $(call try-run,\ - echo '#![allow(missing_docs)]#![feature(no_core)]#![no_core]' | RUSTC_BOOTSTRAP=1\ + echo '$(pound)![allow(missing_docs)]$(pound)![feature(no_core)]$(pound)![no_core]' | RUSTC_BOOTSTRAP=1\ $(1) --sysroot=/dev/null $(filter-out --sysroot=/dev/null --target=%,$(2)) $(3)\ --crate-type=rlib --out-dir=$(TMPOUT) --emit=obj=- - >/dev/null,$(3),$(4)) base-commit: a3cd5f507b72c0532c3345b6913557efab34f405 -- 2.49.0

4 months, 1 week

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+ lib-test_ubsanc-fix-panic-from-test_ubsan_out_of_bounds.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: lib/test_ubsan.c: fix panic from test_ubsan_out_of_bounds has been added to the -mm mm-hotfixes-unstable branch. Its filename is lib-test_ubsanc-fix-panic-from-test_ubsan_out_of_bounds.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Mostafa Saleh <smostafa(a)google.com> Subject: lib/test_ubsan.c: fix panic from test_ubsan_out_of_bounds Date: Mon, 14 Apr 2025 21:36:48 +0000 Running lib_ubsan.ko on arm64 (without CONFIG_UBSAN_TRAP) panics the kernel [ 31.616546] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: test_ubsan_out_of_bounds+0x158/0x158 [test_ubsan] [ 31.646817] CPU: 3 UID: 0 PID: 179 Comm: insmod Not tainted 6.15.0-rc2 #1 PREEMPT [ 31.648153] Hardware name: linux,dummy-virt (DT) [ 31.648970] Call trace: [ 31.649345] show_stack+0x18/0x24 (C) [ 31.650960] dump_stack_lvl+0x40/0x84 [ 31.651559] dump_stack+0x18/0x24 [ 31.652264] panic+0x138/0x3b4 [ 31.652812] __ktime_get_real_seconds+0x0/0x10 [ 31.653540] test_ubsan_load_invalid_value+0x0/0xa8 [test_ubsan] [ 31.654388] init_module+0x24/0xff4 [test_ubsan] [ 31.655077] do_one_initcall+0xd4/0x280 [ 31.655680] do_init_module+0x58/0x2b4 That happens because the test corrupts other data in the stack: 400: d5384108 mrs x8, sp_el0 404: f9426d08 ldr x8, [x8, #1240] 408: f85f83a9 ldur x9, [x29, #-8] 40c: eb09011f cmp x8, x9 410: 54000301 b.ne 470 <test_ubsan_out_of_bounds+0x154> // b.any As there is no guarantee the compiler will order the local variables as declared in the module: volatile char above[4] = { }; /* Protect surrounding memory. */ volatile int arr[4]; volatile char below[4] = { }; /* Protect surrounding memory. */ So, instead of writing out-of-bound, we can read out-of-bound which still triggers UBSAN but doesn't corrupt the stack. Link: https://lkml.kernel.org/r/20250414213648.2660150-1-smostafa@google.com Fixes: 4a26f49b7b3d ubsan: ("expand tests and reporting") Signed-off-by: Mostafa Saleh <smostafa(a)google.com> Cc: Andrey Konovalov <andreyknvl(a)gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a(a)gmail.com> Cc: Macro Elver <elver(a)google.com> Cc: Kees Cook <kees(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- lib/test_ubsan.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) --- a/lib/test_ubsan.c~lib-test_ubsanc-fix-panic-from-test_ubsan_out_of_bounds +++ a/lib/test_ubsan.c @@ -77,18 +77,15 @@ static void test_ubsan_shift_out_of_boun static void test_ubsan_out_of_bounds(void) { - volatile int i = 4, j = 5, k = -1; - volatile char above[4] = { }; /* Protect surrounding memory. */ + volatile int j = 5, k = -1; + volatile int scratch[4] = { }; volatile int arr[4]; - volatile char below[4] = { }; /* Protect surrounding memory. */ - - above[0] = below[0]; UBSAN_TEST(CONFIG_UBSAN_BOUNDS, "above"); - arr[j] = i; + scratch[1] = arr[j]; UBSAN_TEST(CONFIG_UBSAN_BOUNDS, "below"); - arr[k] = i; + scratch[2] = arr[k]; } enum ubsan_test_enum { _ Patches currently in -mm which might be from smostafa(a)google.com are lib-test_ubsanc-fix-panic-from-test_ubsan_out_of_bounds.patch

4 months, 1 week

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[PATCH v2] loop: properly send KOBJ_CHANGED uevent for disk device

by Thomas Weißschuh

The original commit message and the wording "uncork" in the code comment indicate that it is expected that the suppressed event instances are automatically sent after unsuppressing. This is not the case, instead they are discarded. In effect this means that no "changed" events are emitted on the device itself by default. While each discovered partition does trigger a changed event on the device, devices without partitions don't have any event emitted. This makes udev miss the device creation and prompted workarounds in userspace. See the linked util-linux/losetup bug. Explicitly emit the events and drop the confusingly worded comments. Link: https://github.com/util-linux/util-linux/issues/2434 Fixes: 498ef5c777d9 ("loop: suppress uevents while reconfiguring the device") Cc: stable(a)vger.kernel.org Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de> --- Changes in v2: - Use correct Fixes tag - Rework commit message slightly - Rebase onto v6.15-rc1 - Link to v1: https://lore.kernel.org/r/20250317-loop-uevent-changed-v1-1-cb29cb91b62d@li… --- drivers/block/loop.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 674527d770dc669e982a2b441af1171559aa427c..09a725710a21171e0adf5888f929ccaf94e98992 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -667,8 +667,8 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, error = 0; done: - /* enable and uncork uevent now that we are done */ dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 0); + kobject_uevent(&disk_to_dev(lo->lo_disk)->kobj, KOBJ_CHANGE); return error; out_err: @@ -1129,8 +1129,8 @@ static int loop_configure(struct loop_device *lo, blk_mode_t mode, if (partscan) clear_bit(GD_SUPPRESS_PART_SCAN, &lo->lo_disk->state); - /* enable and uncork uevent now that we are done */ dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 0); + kobject_uevent(&disk_to_dev(lo->lo_disk)->kobj, KOBJ_CHANGE); loop_global_unlock(lo, is_loop); if (partscan) --- base-commit: 0af2f6be1b4281385b618cb86ad946eded089ac8 change-id: 20250307-loop-uevent-changed-aa3690f43e03 Best regards, -- Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>

4 months, 2 weeks

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[PATCH] lib/Kconfig.ubsan: Remove 'default UBSAN' from UBSAN_INTEGER_WRAP

by Nathan Chancellor

CONFIG_UBSAN_INTEGER_WRAP is 'default UBSAN', which is problematic for a couple of reasons. The first is that this sanitizer is under active development on the compiler side to come up with a solution that is maintainable on the compiler side and usable on the kernel side. As a result of this, there are many warnings when the sanitizer is enabled that have no clear path to resolution yet but users may see them and report them in the meantime. The second is that this option was renamed from CONFIG_UBSAN_SIGNED_WRAP, meaning that if a configuration has CONFIG_UBSAN=y but CONFIG_UBSAN_SIGNED_WRAP=n and it is upgraded via olddefconfig (common in non-interactive scenarios such as CI), CONFIG_UBSAN_INTEGER_WRAP will be silently enabled again. Remove 'default UBSAN' from CONFIG_UBSAN_INTEGER_WRAP until it is ready for regular usage and testing from a broader community than the folks actively working on the feature. Cc: stable(a)vger.kernel.org Fixes: 557f8c582a9b ("ubsan: Reintroduce signed overflow sanitizer") Signed-off-by: Nathan Chancellor <nathan(a)kernel.org> --- lib/Kconfig.ubsan | 1 - 1 file changed, 1 deletion(-) diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan index 4216b3a4ff21..f6ea0c5b5da3 100644 --- a/lib/Kconfig.ubsan +++ b/lib/Kconfig.ubsan @@ -118,7 +118,6 @@ config UBSAN_UNREACHABLE config UBSAN_INTEGER_WRAP bool "Perform checking for integer arithmetic wrap-around" - default UBSAN depends on !COMPILE_TEST depends on $(cc-option,-fsanitize-undefined-ignore-overflow-pattern=all) depends on $(cc-option,-fsanitize=signed-integer-overflow) --- base-commit: 26fe62cc5e8420d5c650d6b86fee061952d348cd change-id: 20250414-drop-default-ubsan-integer-wrap-bf0eb6efb29b Best regards, -- Nathan Chancellor <nathan(a)kernel.org>

4 months, 2 weeks

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[PATCH bpf v2] libbpf: Fix buffer overflow in bpf_object__init_prog

by Viktor Malik

As reported by CVE-2025-29481 [1], it is possible to corrupt a BPF ELF file such that arbitrary BPF instructions are loaded by libbpf. This can be done by setting a symbol (BPF program) section offset to a large (unsigned) number such that <section start + symbol offset> overflows and points before the section data in the memory. Consider the situation below where: - prog_start = sec_start + symbol_offset <-- size_t overflow here - prog_end = prog_start + prog_size prog_start sec_start prog_end sec_end | | | | v v v v .....................|################################|............ The CVE report in [1] also provides a corrupted BPF ELF which can be used as a reproducer: $ readelf -S crash Section Headers: [Nr] Name Type Address Offset Size EntSize Flags Link Info Align ... [ 2] uretprobe.mu[...] PROGBITS 0000000000000000 00000040 0000000000000068 0000000000000000 AX 0 0 8 $ readelf -s crash Symbol table '.symtab' contains 8 entries: Num: Value Size Type Bind Vis Ndx Name ... 6: ffffffffffffffb8 104 FUNC GLOBAL DEFAULT 2 handle_tp Here, the handle_tp prog has section offset ffffffffffffffb8, i.e. will point before the actual memory where section 2 is allocated. This is also reported by AddressSanitizer: ================================================================= ==1232==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7c7302fe0000 at pc 0x7fc3046e4b77 bp 0x7ffe64677cd0 sp 0x7ffe64677490 READ of size 104 at 0x7c7302fe0000 thread T0 #0 0x7fc3046e4b76 in memcpy (/lib64/libasan.so.8+0xe4b76) #1 0x00000040df3e in bpf_object__init_prog /src/libbpf/src/libbpf.c:856 #2 0x00000040df3e in bpf_object__add_programs /src/libbpf/src/libbpf.c:928 #3 0x00000040df3e in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3930 #4 0x00000040df3e in bpf_object_open /src/libbpf/src/libbpf.c:8067 #5 0x00000040f176 in bpf_object__open_file /src/libbpf/src/libbpf.c:8090 #6 0x000000400c16 in main /poc/poc.c:8 #7 0x7fc3043d25b4 in __libc_start_call_main (/lib64/libc.so.6+0x35b4) #8 0x7fc3043d2667 in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x3667) #9 0x000000400b34 in _start (/poc/poc+0x400b34) 0x7c7302fe0000 is located 64 bytes before 104-byte region [0x7c7302fe0040,0x7c7302fe00a8) allocated by thread T0 here: #0 0x7fc3046e716b in malloc (/lib64/libasan.so.8+0xe716b) #1 0x7fc3045ee600 in __libelf_set_rawdata_wrlock (/lib64/libelf.so.1+0xb600) #2 0x7fc3045ef018 in __elf_getdata_rdlock (/lib64/libelf.so.1+0xc018) #3 0x00000040642f in elf_sec_data /src/libbpf/src/libbpf.c:3740 The problem here is that currently, libbpf only checks that the program end is within the section bounds. There used to be a check `while (sec_off < sec_sz)` in bpf_object__add_programs, however, it was removed by commit 6245947c1b3c ("libbpf: Allow gaps in BPF program sections to support overriden weak functions"). Put the above condition back to bpf_object__init_prog to make sure that the program start is also within the bounds of the section to avoid the potential buffer overflow. [1] https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md Reported-by: lmarch2 <2524158037(a)qq.com> Cc: stable(a)vger.kernel.org Fixes: 6245947c1b3c ("libbpf: Allow gaps in BPF program sections to support overriden weak functions") Link: https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md Link: https://www.cve.org/CVERecord?id=CVE-2025-29481 Signed-off-by: Viktor Malik <vmalik(a)redhat.com> Reviewed-by: Shung-Hsi Yu <shung-hsi.yu(a)suse.com> --- tools/lib/bpf/libbpf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 6b85060f07b3..d0ece3c9618e 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -896,7 +896,7 @@ bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data, return -LIBBPF_ERRNO__FORMAT; } - if (sec_off + prog_sz > sec_sz) { + if (sec_off >= sec_sz || sec_off + prog_sz > sec_sz) { pr_warn("sec '%s': program at offset %zu crosses section boundary\n", sec_name, sec_off); return -LIBBPF_ERRNO__FORMAT; -- 2.49.0

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Linux-stable-mirror April 2025