Messages in this thread Patch in this message | | | Date | Fri, 13 Mar 2009 18:10:42 -0700 | From | Greg KH <> | Subject | [patch 065/114] x86-64: fix int $0x80 -ENOSYS return |
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2.6.28-stable review patch. If anyone has any objections, please let us know.
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From: Roland McGrath <roland@redhat.com>
commit c09249f8d1b84344eca882547afdbffee8c09d14 upstream.
One of my past fixes to this code introduced a different new bug. When using 32-bit "int $0x80" entry for a bogus syscall number, the return value is not correctly set to -ENOSYS. This only happens when neither syscall-audit nor syscall tracing is enabled (i.e., never seen if auditd ever started). Test program:
/* gcc -o int80-badsys -m32 -g int80-badsys.c Run on x86-64 kernel. Note to reproduce the bug you need auditd never to have started. */
#include <errno.h> #include <stdio.h>
int main (void) { long res; asm ("int $0x80" : "=a" (res) : "0" (99999)); printf ("bad syscall returns %ld\n", res); return res != -ENOSYS; }
The fix makes the int $0x80 path match the sysenter and syscall paths.
Reported-by: Dmitry V. Levin <ldv@altlinux.org> Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Chuck Ebbert <cebbert@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- arch/x86/ia32/ia32entry.S | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
--- a/arch/x86/ia32/ia32entry.S +++ b/arch/x86/ia32/ia32entry.S @@ -418,9 +418,9 @@ ENTRY(ia32_syscall) orl $TS_COMPAT,TI_status(%r10) testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%r10) jnz ia32_tracesys -ia32_do_syscall: cmpl $(IA32_NR_syscalls-1),%eax - ja int_ret_from_sys_call /* ia32_tracesys has set RAX(%rsp) */ + ja ia32_badsys +ia32_do_call: IA32_ARG_FIXUP call *ia32_sys_call_table(,%rax,8) # xxx: rip relative ia32_sysret: @@ -435,7 +435,9 @@ ia32_tracesys: call syscall_trace_enter LOAD_ARGS32 ARGOFFSET /* reload args from stack in case ptrace changed it */ RESTORE_REST - jmp ia32_do_syscall + cmpl $(IA32_NR_syscalls-1),%eax + ja int_ret_from_sys_call /* ia32_tracesys has set RAX(%rsp) */ + jmp ia32_do_call END(ia32_syscall) ia32_badsys:
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