Commit 0acd4ab8 authored by Rémi Denis-Courmont's avatar Rémi Denis-Courmont Committed by Laurent Vivier
Browse files

linux-user: check valid address in access_ok() 



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: f6768aa1 ("target/arm: fix AArch64 virtual address space size")
Signed-off-by: default avatarRémi Denis-Courmont <remi@remlab.net>
Signed-off-by: default avatarLaurent Vivier <lvivier@redhat.com>
Message-Id: <20190704084115.24713-1-lvivier@redhat.com>
Signed-off-by: default avatarLaurent Vivier <laurent@vivier.eu>
parent 4ced996f

include/exec/cpu_ldst.h

+4 −0
Original line number Diff line number Diff line
@@ -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)

linux-user/qemu.h

+3 −1
Original line number Diff line number Diff line
@@ -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;

}