55 lines
2.4 KiB
Diff
55 lines
2.4 KiB
Diff
commit e1fe22368e4fbc13ce300d89802b7fcc0d5cfb38
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Author: Michael Jeanson <mjeanson@efficios.com>
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Date: Fri Feb 14 13:54:22 2025 -0500
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nptl: clear the whole rseq area before registration
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Due to the extensible nature of the rseq area we can't explictly
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initialize fields that are not part of the ABI yet. It was agreed with
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upstream that all new fields will be documented as zero initialized by
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userspace. Future kernels configured with CONFIG_DEBUG_RSEQ will
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validate the content of all fields during registration.
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Replace the explicit field initialization with a memset of the whole
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rseq area which will cover fields as they are added to future kernels.
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Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
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Reviewed-by: Florian Weimer <fweimer@redhat.com>
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(cherry picked from commit 689a62a4217fae78b9ce0db781dc2a421f2b1ab4)
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diff --git a/sysdeps/nptl/dl-tls_init_tp.c b/sysdeps/nptl/dl-tls_init_tp.c
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index 7803e19fd16ad803..ed10185e3708f4b6 100644
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--- a/sysdeps/nptl/dl-tls_init_tp.c
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+++ b/sysdeps/nptl/dl-tls_init_tp.c
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@@ -23,6 +23,7 @@
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#include <tls.h>
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#include <rseq-internal.h>
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#include <thread_pointer.h>
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+#include <dl-symbol-redir-ifunc.h>
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#define TUNABLE_NAMESPACE pthread
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#include <dl-tunables.h>
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diff --git a/sysdeps/unix/sysv/linux/rseq-internal.h b/sysdeps/unix/sysv/linux/rseq-internal.h
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index ef3eab1fefd4d90d..76de2b7ff079eb0f 100644
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--- a/sysdeps/unix/sysv/linux/rseq-internal.h
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+++ b/sysdeps/unix/sysv/linux/rseq-internal.h
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@@ -52,13 +52,12 @@ rseq_register_current_thread (struct pthread *self, bool do_rseq)
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but still expected size 32. */
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size = RSEQ_AREA_SIZE_INITIAL;
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- /* Initialize the rseq fields that are read by the kernel on
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- registration, there is no guarantee that struct pthread is
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- cleared on all architectures. */
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+ /* Initialize the whole rseq area to zero prior to registration. */
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+ memset (&self->rseq_area, 0, size);
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+
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+ /* Set the cpu_id field to RSEQ_CPU_ID_UNINITIALIZED, this is checked by
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+ the kernel at registration when CONFIG_DEBUG_RSEQ is enabled. */
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THREAD_SETMEM (self, rseq_area.cpu_id, RSEQ_CPU_ID_UNINITIALIZED);
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- THREAD_SETMEM (self, rseq_area.cpu_id_start, 0);
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- THREAD_SETMEM (self, rseq_area.rseq_cs, 0);
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- THREAD_SETMEM (self, rseq_area.flags, 0);
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int ret = INTERNAL_SYSCALL_CALL (rseq, &self->rseq_area,
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size, 0, RSEQ_SIG);
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