Are you sure that the bug is really in kqemu ? It is possible that your
guest kernel implements a security system which prevents self modifying
code using segment limits which QEMU does not check (but kqemu checks
them !).
Regards,
Fabrice.
Even Rouault wrote:
Guest OS : Linux 2.6.15-1.2054_FC5 i686 (Fedora Core 5 i386)
Host OS: Linux 2.6.12-10-amd64-k8 #1 x86_64 (Ubuntu 5.10 amd64)
QEMU Version : today CVS compiled with kqemu support
KQEMU : 1.3.0pre6
Binary used : qemu-system-x86-64 (so kqemu user-mode is used)
I'm running the simple C code attached. With kqemu user-mode, this fails
(sigsegv) with the following warning in dmesg :
audit(1146505373.813:12): avc: denied { execheap } for pid=1860
comm="selfmodifying scontext=user_u:system_r:unconfined_t:s0
tcontext=user_u:system_r:unconfined_t:s0 tclass=process
Erreur de segmentation
Without kqemu enabled, it runs fine.
------------------------------------------------------------------------
#define _XOPEN_SOURCE 600
#include <sys/mman.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
int main(int argc, char** argv)
{
int pagesize = getpagesize();
unsigned char* addr = NULL;
posix_memalign((void**)&addr, pagesize, pagesize);
mprotect(addr, pagesize, PROT_WRITE | PROT_READ | PROT_EXEC);
addr[0] = 0x8b; addr[1] = 0x44; addr[2] = 0x24; addr[3] = 0x04; /* mov
0x4(%esp),%eax */
addr[4] = 0x83; addr[5] = 0xc0; addr[6] = 0x01; /* add $0x1,%eax */
addr[7] = 0xc3; /* ret */
printf("10+1=%d\n", ((int (*)(int))addr)(10));
free(addr);
return 0;
}
------------------------------------------------------------------------
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