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[Qemu-devel] [PULL 3/3] linux-user: check valid address in access_ok()
From: |
Laurent Vivier |
Subject: |
[Qemu-devel] [PULL 3/3] linux-user: check valid address in access_ok() |
Date: |
Wed, 17 Jul 2019 16:54:18 +0200 |
From: Rémi Denis-Courmont <address@hidden>
Fix a crash with LTP testsuite and aarch64:
tst_test.c:1015: INFO: Timeout per run is 0h 05m 00s
qemu-aarch64: .../qemu/accel/tcg/translate-all.c:2522: page_check_range:
Assertion `start < ((target_ulong)1 << L1_MAP_ADDR_SPACE_BITS)' failed.
qemu:handle_cpu_signal received signal outside vCPU context @ pc=0x60001554
page_check_range() should never be called with address outside the guest
address space. This patch adds a guest_addr_valid() check in access_ok()
to only call page_check_range() with a valid address.
Fixes: f6768aa1b4c6 ("target/arm: fix AArch64 virtual address space size")
Signed-off-by: Rémi Denis-Courmont <address@hidden>
Signed-off-by: Laurent Vivier <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Laurent Vivier <address@hidden>
---
include/exec/cpu_ldst.h | 4 ++++
linux-user/qemu.h | 4 +++-
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/include/exec/cpu_ldst.h b/include/exec/cpu_ldst.h
index 9de8c933031b..9151fdb042c4 100644
--- a/include/exec/cpu_ldst.h
+++ b/include/exec/cpu_ldst.h
@@ -62,7 +62,11 @@ typedef uint64_t abi_ptr;
/* All direct uses of g2h and h2g need to go away for usermode softmmu. */
#define g2h(x) ((void *)((unsigned long)(abi_ptr)(x) + guest_base))
+#if HOST_LONG_BITS <= TARGET_VIRT_ADDR_SPACE_BITS
+#define guest_addr_valid(x) (1)
+#else
#define guest_addr_valid(x) ((x) <= GUEST_ADDR_MAX)
+#endif
#define h2g_valid(x) guest_addr_valid((unsigned long)(x) - guest_base)
static inline int guest_range_valid(unsigned long start, unsigned long len)
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index fab287b7ec50..4258e4162d26 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -456,7 +456,9 @@ extern unsigned long guest_stack_size;
static inline int access_ok(int type, abi_ulong addr, abi_ulong size)
{
- return page_check_range((target_ulong)addr, size,
+ return guest_addr_valid(addr) &&
+ (size == 0 || guest_addr_valid(addr + size - 1)) &&
+ page_check_range((target_ulong)addr, size,
(type == VERIFY_READ) ? PAGE_READ : (PAGE_READ |
PAGE_WRITE)) == 0;
}
--
2.21.0