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118 lines
4.2 KiB
118 lines
4.2 KiB
4 weeks ago
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commit 4f5704ea347e52ac3f272d1341da10aed6e9973e
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Author: Florian Weimer <fweimer@redhat.com>
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Date: Tue Dec 10 16:17:06 2024 +0100
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powerpc: Use correct procedure call standard for getrandom vDSO call (bug 32440)
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A plain indirect function call does not work on POWER because
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success and failure are signaled through a flag register, and
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not via the usual Linux negative return value convention.
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This has potential security impact, in two ways: the return value
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could be out of bounds (EAGAIN is 11 on powerpc6le), and no
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random bytes have been written despite the non-error return value.
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Fixes commit 461cab1de747f3842f27a5d24977d78d561d45f9 ("linux: Add
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support for getrandom vDSO").
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Reported-by: Ján Stanček <jstancek@redhat.com>
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Reviewed-by: Carlos O'Donell <carlos@redhat.com>
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diff --git a/stdlib/Makefile b/stdlib/Makefile
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index 44a118da59f96c17..d3f55249434cc3e8 100644
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--- a/stdlib/Makefile
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+++ b/stdlib/Makefile
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@@ -276,6 +276,7 @@ tests := \
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tst-cxa_atexit \
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tst-environ \
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tst-getrandom \
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+ tst-getrandom-errno \
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tst-getrandom2 \
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tst-labs \
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tst-limits \
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diff --git a/stdlib/tst-getrandom-errno.c b/stdlib/tst-getrandom-errno.c
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new file mode 100644
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index 0000000000000000..75a60e53ad4e7350
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--- /dev/null
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+++ b/stdlib/tst-getrandom-errno.c
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@@ -0,0 +1,37 @@
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+/* Test errno handling in getrandom (bug 32440).
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+ Copyright (C) 2024 Free Software Foundation, Inc.
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+ This file is part of the GNU C Library.
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+
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+ The GNU C Library is free software; you can redistribute it and/or
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+ modify it under the terms of the GNU Lesser General Public
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+ License as published by the Free Software Foundation; either
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+ version 2.1 of the License, or (at your option) any later version.
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+
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+ The GNU C Library is distributed in the hope that it will be useful,
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+ but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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+ Lesser General Public License for more details.
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+
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+ You should have received a copy of the GNU Lesser General Public
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+ License along with the GNU C Library; if not, see
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+ <https://www.gnu.org/licenses/>. */
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+
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+#include <errno.h>
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+#include <stdlib.h>
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+#include <support/check.h>
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+#include <sys/random.h>
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+
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+static
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+int do_test (void)
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+{
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+ errno = -1181968554; /* Just a random value. */
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+ char buf[4];
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+ int ret = getrandom (buf, sizeof (buf), -1); /* All flags set. */
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+ if (errno != ENOSYS)
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+ TEST_COMPARE (errno, EINVAL);
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+ TEST_COMPARE (ret, -1);
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+
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+ return 0;
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+}
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+
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+#include <support/test-driver.c>
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diff --git a/sysdeps/unix/sysv/linux/getrandom.c b/sysdeps/unix/sysv/linux/getrandom.c
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index c8c578263da456b2..0dc8fa6e65b9ef6a 100644
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--- a/sysdeps/unix/sysv/linux/getrandom.c
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+++ b/sysdeps/unix/sysv/linux/getrandom.c
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@@ -20,6 +20,8 @@
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#include <errno.h>
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#include <unistd.h>
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#include <sysdep-cancel.h>
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+#include <sysdep.h>
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+#include <sysdep-vdso.h>
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static inline ssize_t
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getrandom_syscall (void *buffer, size_t length, unsigned int flags,
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@@ -201,11 +203,12 @@ getrandom_vdso (void *buffer, size_t length, unsigned int flags, bool cancel)
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cancellation bridge (__syscall_cancel_arch), use GRND_NONBLOCK so there
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is no potential unbounded blocking in the kernel. It should be a rare
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situation, only at system startup when RNG is not initialized. */
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- ssize_t ret = GLRO (dl_vdso_getrandom) (buffer,
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- length,
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- flags | GRND_NONBLOCK,
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- state,
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- state_size);
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+ long int ret = INTERNAL_VSYSCALL_CALL (GLRO (dl_vdso_getrandom), 5,
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+ buffer,
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+ length,
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+ flags | GRND_NONBLOCK,
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+ state,
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+ state_size);
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if (INTERNAL_SYSCALL_ERROR_P (ret))
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{
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/* Fallback to the syscall if the kernel would block. */
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@@ -241,7 +244,9 @@ __getrandom_early_init (_Bool initial)
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uint32_t mmap_flags;
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uint32_t reserved[13];
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} params;
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- if (GLRO(dl_vdso_getrandom) (NULL, 0, 0, ¶ms, ~0UL) == 0)
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+ long int ret = INTERNAL_VSYSCALL_CALL (GLRO(dl_vdso_getrandom),
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+ 5, NULL, 0, 0, ¶ms, ~0UL);
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+ if (! INTERNAL_SYSCALL_ERROR_P (ret))
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{
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/* Align each opaque state to L1 data cache size to avoid false
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sharing. If the size can not be obtained, use the kernel
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