linux-stable.git/lib, branch linux-5.15.y

bootconfig: fix NULL-pointer arithmetic in xbc_snprint_cmdline()

2026-08-23T12:17:24+00:00

[ Upstream commit dec4d8118c179b3d12bca7e609054c6011c4f2ce ]

xbc_snprint_cmdline() is meant to be called twice: first with
buf=NULL, size=0 to probe the rendered length, then with a real
buffer to fill it (the standard snprintf() two-pass pattern). The
probe call makes the function compute "buf + size" (NULL + 0) and,
on every iteration, advance "buf += ret" from that NULL base and
pass the result back into snprintf().

Pointer arithmetic on a NULL pointer is undefined behavior. It is
harmless in the in-kernel callers today, but the follow-up patches
run this same code in the userspace tools/bootconfig parser at kernel
build time, where host UBSan / FORTIFY_SOURCE abort the build.

Track a running written length (size_t) instead of mutating @buf, and
only form "buf + len" when @buf is non-NULL. snprintf(NULL, 0, ...)
is itself well defined and returns the would-be length, so the
two-pass "probe then fill" usage returns identical byte counts.

Link: https://lore.kernel.org/all/20260626-bootconfig_using_tools-v7-1-24ab72139c29@debian.org/

Fixes: 51887d03aca1 ("bootconfig: init: Allow admin to use bootconfig for kernel command line")
Cc: stable@vger.kernel.org
Signed-off-by: Breno Leitao 
Signed-off-by: Masami Hiramatsu (Google) 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

bootconfig: move xbc_snprint_cmdline() to lib/bootconfig.c

2026-08-23T12:17:24+00:00

[ Upstream commit 5a643e4623238e14b03d75ca0d4eda0645720cee ]

Move xbc_snprint_cmdline() from init/main.c to lib/bootconfig.c so the
function (and its xbc_namebuf scratch buffer) becomes part of the shared
parser library. tools/bootconfig already compiles lib/bootconfig.c
directly, which lets a follow-up patch reuse the same renderer in the
userspace tool to convert a bootconfig file into a flat cmdline string
at build time.

No functional change.

Link: https://lore.kernel.org/all/20260508-bootconfig_using_tools-v1-1-1132219aa773@debian.org/

Signed-off-by: Breno Leitao 
Signed-off-by: Masami Hiramatsu (Google) 
Stable-dep-of: dec4d8118c17 ("bootconfig: fix NULL-pointer arithmetic in xbc_snprint_cmdline()")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

audit: use 'unsigned int' instead of 'unsigned'

2026-08-23T12:17:18+00:00

[ Upstream commit 8b226771014beab1292081151a99530886ce54b4 ]

Address checkpatch.pl warning below, across the audit subsystem:

  WARNING: Prefer 'unsigned int' to bare use of 'unsigned'

Minor cleanup, no functional changes.

Signed-off-by: Ricardo Robaina 
Signed-off-by: Paul Moore 
Stable-dep-of: 81905b5acbe7 ("audit: fix recursive locking deadlock in audit_dupe_exe()")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

rhashtable: clear stale iter->p on table restart

2026-08-19T15:14:08+00:00

[ Upstream commit 8173f7e2ce67e6ca1d4763f3da14e5b01ce77456 ]

rhashtable_walk_start_check() has two restart paths when resuming a walk.
When iter->walker.tbl is valid, it re-validates iter->p against the table
and sets iter->p = NULL if the object is gone.  When iter->walker.tbl is
NULL (table was freed during resize), it resets slot and skip but forgets
to clear iter->p.

rhashtable_walk_next() then dereferences the stale iter->p, reading
freed memory.  This is a use-after-free.

Any caller that does multi-fragment rhashtable walks across
walk_stop/walk_start boundaries is affected.  Concrete cases include
netlink_diag (__netlink_diag_dump in net/netlink/diag.c) and TIPC
(tipc_nl_sk_walk in net/tipc/socket.c).

Crash stack (netlink_diag):
  BUG: KASAN: slab-use-after-free in rhashtable_walk_next+0x365/0x3c0
  Read of size 8 at addr ffff88801a9d2438 (freed kmalloc-2k, offset 1080)
  Call Trace:
   rhashtable_walk_next+0x365/0x3c0 (lib/rhashtable.c:1016)
   __netlink_diag_dump+0x160/0x760 (net/netlink/diag.c:122)
   netlink_diag_dump+0xc2/0x240
   netlink_dump+0x5bc/0x1270
   netlink_recvmsg+0x7a3/0x980
   sock_recvmsg+0x1bc/0x200
   __sys_recvfrom+0x1d4/0x2c0

Fixes: 5d240a8936f6 ("rhashtable: improve rhashtable_walk stability when stop/start used.")
Cc: 
Reported-by: AutonomousCodeSecurity@microsoft.com
Reported-by: Yuan Tan 
Closes: https://lore.kernel.org/linux-crypto/CAB8m9Wh559e+=n8z51gB8DrbEyCc2mc0MgGjrRR6_VXBmU=2AQ@mail.gmail.com
Signed-off-by: Cen Zhang (Microsoft) 
Reviewed-by: NeilBrown 
Signed-off-by: Herbert Xu 
Signed-off-by: Sasha Levin

assoc_array: trim the final shortcut word using the current chunk end

2026-08-19T15:14:06+00:00

[ Upstream commit a82c8a05e86f3f84e09698f65b4515b5d04633f6 ]

assoc_array_walk() masks off the bits past shortcut->skip_to_level in the
word that contains skip_to_level, gated on
round_up(sc_level, ASSOC_ARRAY_KEY_CHUNK_SIZE) > skip_to_level.

That guard is wrong in two opposite ways:

 - When sc_level is word-aligned (every word after the first) round_up()
   is a no-op, so the guard is sc_level > skip_to_level and never fires for
   the word that holds skip_to_level.  A shortcut that spans more than one
   word and ends in the middle of its last word leaves that word untrimmed,
   and its stale high bits leak into the dissimilarity word and can steer
   the walk down the wrong descendant.

 - When sc_level is unaligned (the first word) and skip_to_level sits on
   the next chunk boundary, sc_level + CHUNK would exceed skip_to_level and
   fire the trim with shift = skip_to_level & CHUNK_MASK == 0, which clears
   the whole dissimilarity word and makes a differing shortcut compare
   equal.

Use the end of the chunk that contains sc_level instead:

	skip_to_level < round_down(sc_level, CHUNK) + CHUNK

For an aligned sc_level whose word holds skip_to_level this now fires (the
first bug); for an unaligned sc_level with skip_to_level on the following
boundary it does not, so shift is never 0 when the branch runs and the trim
never clears the whole word.

Fixes: 3cb989501c26 ("Add a generic associative array implementation.")
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Michael Bommarito 
Reviewed-by: Jarkko Sakkinen 
Tested-by: Jarkko Sakkinen 
Link: https://lore.kernel.org/r/20260719161505.2423935-4-michael.bommarito@gmail.com
Signed-off-by: Jarkko Sakkinen 
Signed-off-by: Sasha Levin

lib/test_meminit: use && for bools

2026-07-24T13:51:32+00:00

[ Upstream commit 8e0c2085c978ed6d9764d79fc785920360096f21 ]

As pointed out by Dan Carpenter, test_kmemcache() was using a bitwise AND
on two bools instead of a boolean AND.  Fix this for the sake of code
cleanliness.

Link: https://lore.kernel.org/20260504100637.1535762-1-glider@google.com
Fixes: 5015a300a522 ("lib: introduce test_meminit module")
Signed-off-by: Alexander Potapenko 
Reported-by: Dan Carpenter 
Closes: https://lore.kernel.org/kernel-janitors/afOcIan1ap9kD26M@stanley.mountain/
Reviewed-by: Andrew Morton 
Signed-off-by: Andrew Morton 
Signed-off-by: Sasha Levin

tracing: Prevent out-of-bounds read in glob matching

2026-07-24T13:51:25+00:00

commit 0a6070839b1ef276d5b05bedfb787743e140fb17 upstream.

String event fields are not necessarily NUL-terminated, so the filter
predicate functions (filter_pred_string(), filter_pred_strloc() and
filter_pred_strrelloc()) pass the field length to the regex match
callbacks, and the length-aware matchers honour it.

regex_match_glob() was the exception: it ignored the length and called
glob_match(), which scans the string until it hits a NUL byte. Some
string fields are not NUL-terminated. One example is the dynamic char
array of the xfs_* namespace tracepoints, which is copied without a
trailing NUL. For such a field, glob matching reads past the end of
the event field, causing a KASAN slab-out-of-bounds read in
glob_match(), reached via regex_match_glob() and filter_match_preds()
from the xfs_lookup tracepoint.

Add a length-bounded glob_match_len() and use it from regex_match_glob()
so glob matching always stops at the field boundary. The matching loop
is factored into a shared helper so glob_match() keeps its behaviour.

Fixes: 60f1d5e3bac4 ("ftrace: Support full glob matching")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/da1aaf125fc3b63320b0c540fd6afa7c3d5b4f1a.1782836943.git.hhhuang@smu.edu.sg
Reported-by: Yuan Tan 
Reported-by: Yifan Wu 
Reported-by: Juefei Pu 
Reported-by: Zhengchuan Liang 
Reported-by: Xin Liu 
Assisted-by: Codex:GPT-5.4
Signed-off-by: Huihui Huang 
Signed-off-by: Ren Wei 
Acked-by: Masami Hiramatsu (Google) 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

debugobjects: Plug race against a concurrent OOM disable

2026-07-24T13:51:21+00:00

commit b81dde13cc163450dcb402dcc915ef13ba241e01 upstream.

syzbot reported a puzzling splat:

   WARNING: kernel/time/hrtimer.c:443 at stub_timer+0xa/0x20

stub_timer() is installed as timer callback function in
hrtimer_fixup_assert_init(), which is invoked when
debug_object_assert_init() can't find a shadow object. In that case debug
objects emits a warning about it before invoking the fixup.

Though the provided console log lacks this warning and instead has the
following a few seconds before the splat:

     ODEBUG: Out of memory. ODEBUG disabled

So the object was looked up in debug_object_assert_init() and the lookup
failed due a concurrent out of memory situation which disabled debug
objects and freed the shadow objects:

debug_object_assert_init()
        if (!debug_objects_enabled)
        	return;                         obj = alloc();
                				if (!obj) {
							// Out of memory
                                                	debug_objects_enabled = false;
                                                        free_objects();
        obj = lookup_or_alloc();

        // The lookup failed because the other side
        // removed the objects, so this returns
        // an error code as the object in question
        // is not statically initialized

	if (!IS_ERR_OR_NULL(obj))
        	return;
        if (!obj) {
        	debug_oom();
                return;
        }

        print(...)
           if (!debug_objects_enabled)
                return;

        fixup(...)

The debug object splat is skipped because debug_objects_enabled is false,
but the fixup callback is invoked unconditionally, which makes the timer
disfunctional.

This is only a problem in debug_object_assert_init() and
debug_object_activate() as both have to handle statically initialized
objects and therefore must handle the error pointer return case
gracefully. All other places only handle the found/not found case and the
NULL pointer return is a signal for OOM. Otherwise they get a valid shadow
object.

Plug the hole by checking whether debug objects are still enabled before
invoking the print and fixup function in those two places.

Fixes: b84d435cc228 ("debugobjects: Extend to assert that an object is initialized")
Reported-by: syzbot+5e8dda76ca21dae314b6@syzkaller.appspotmail.com
Signed-off-by: Thomas Gleixner 
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/874iiwlzlb.ffs@fw13
Signed-off-by: Greg Kroah-Hartman

lib/crypto: mpi: Fix integer underflow in mpi_read_raw_from_sgl()

2026-06-19T11:33:39+00:00

commit 8c2f1288250a90a4b5cabed5d888d7e3aeed4035 upstream.

Yiming reports an integer underflow in mpi_read_raw_from_sgl() when
subtracting "lzeros" from the unsigned "nbytes".

For this to happen, the scatterlist "sgl" needs to occupy more bytes
than the "nbytes" parameter and the first "nbytes + 1" bytes of the
scatterlist must be zero.  Under these conditions, the while loop
iterating over the scatterlist will count more zeroes than "nbytes",
subtract the number of zeroes from "nbytes" and cause the underflow.

When commit 2d4d1eea540b ("lib/mpi: Add mpi sgl helpers") originally
introduced the bug, it couldn't be triggered because all callers of
mpi_read_raw_from_sgl() passed a scatterlist whose length was equal to
"nbytes".

However since commit 63ba4d67594a ("KEYS: asymmetric: Use new crypto
interface without scatterlists"), the underflow can now actually be
triggered.  When invoking a KEYCTL_PKEY_ENCRYPT system call with a
larger "out_len" than "in_len" and filling the "in" buffer with zeroes,
crypto_akcipher_sync_prep() will create an all-zero scatterlist used for
both the "src" and "dst" member of struct akcipher_request and thereby
fulfil the conditions to trigger the bug:

  sys_keyctl()
    keyctl_pkey_e_d_s()
      asymmetric_key_eds_op()
        software_key_eds_op()
          crypto_akcipher_sync_encrypt()
            crypto_akcipher_sync_prep()
              crypto_akcipher_encrypt()
                rsa_enc()
                  mpi_read_raw_from_sgl()

To the user this will be visible as a DoS as the kernel spins forever,
causing soft lockup splats as a side effect.

Fix it.

Reported-by: Yiming Qian  # off-list
Fixes: 2d4d1eea540b ("lib/mpi: Add mpi sgl helpers")
Signed-off-by: Lukas Wunner 
Cc: stable@vger.kernel.org # v4.4+
Reviewed-by: Ignat Korchagin 
Reviewed-by: Jarkko Sakkinen 
Link: https://lore.kernel.org/r/59eca92ff4f87e2081777f1423a0efaaadcfdb39.1776003111.git.lukas@wunner.de
Signed-off-by: Eric Biggers 
Signed-off-by: Greg Kroah-Hartman

iommu, debugobjects: avoid gcc-16.1 section mismatch warnings

2026-06-19T11:33:28+00:00

commit 4c9ad387aa2d6785299722e54224d34764edaeb3 upstream.

gcc-16 has gained some more advanced inter-procedual optimization
techniques that enable it to inline the dummy_tlb_add_page() and
dummy_tlb_flush() function pointers into a specialized version of
__arm_v7s_unmap:

WARNING: modpost: vmlinux: section mismatch in reference: __arm_v7s_unmap+0x2cc (section: .text) -> dummy_tlb_add_page (section: .init.text)
ERROR: modpost: Section mismatches detected.

>From what I can tell, the transformation is correct, as this is only
called when __arm_v7s_unmap() is called from arm_v7s_do_selftests(),
which is also __init. Since __arm_v7s_unmap() however is not __init,
gcc cannot inline the inner function calls directly.

In debug_objects_selftest(), the same thing happens. Both the
caller and the leaf function are __init, but the IPA pulls
it into a non-init one:

WARNING: modpost: vmlinux: section mismatch in reference: lookup_object_or_alloc+0x7c (section: .text.lookup_object_or_alloc) -> is_static_object (section: .init.text)

Marking the affected functions as not "__init" would reliably avoid this
issue but is not a good solution because it removes an otherwise correct
annotation. I tried marking the functions as 'noinline', but that ended
up not covering all the affected configurations.

With some more experimenting, I found that marking these functions as
__attribute__((noipa)) is both logical and reliable.

In order to keep the syntax readable, add a custom macro for this in
include/linux/compiler_attributes.h next to other related macros and
use it to annotate both files.

Link: https://lore.kernel.org/all/abRB6g-48ZX6Yl2r@willie-the-truck/
Cc: Will Deacon 
Cc: Thomas Gleixner 
Cc: Andrew Morton 
Cc: Miguel Ojeda 
Cc: linux-kbuild@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Arnd Bergmann 
Acked-by: Will Deacon 
Acked-by: Thomas Gleixner 
Acked-by: Miguel Ojeda 
Signed-off-by: Joerg Roedel 
Signed-off-by: Greg Kroah-Hartman