From: Roland McGrath Date: Sat, 7 Feb 2009 02:15:18 +0000 (-0800) Subject: x86-64: fix int $0x80 -ENOSYS return X-Git-Tag: Ubuntu-snapdragon-4.4.0-1050.54~27707^2 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=c09249f8d1b84344eca882547afdbffee8c09d14;p=mirror_ubuntu-artful-kernel.git x86-64: fix int $0x80 -ENOSYS return 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 #include 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 Signed-off-by: Roland McGrath --- diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S index 256b00b61892..5a0d76dc56a4 100644 --- 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: