forked from Minki/linux
x86_64 ia32 syscall audit fast-path
This adds fast paths for 32-bit syscall entry and exit when TIF_SYSCALL_AUDIT is set, but no other kind of syscall tracing. These paths does not need to save and restore all registers as the general case of tracing does. Avoiding the iret return path when syscall audit is enabled helps performance a lot. Signed-off-by: Roland McGrath <roland@redhat.com>
This commit is contained in:
Roland McGrath
parent
86a1c34a92
commit
5cbf1565f2
@ -15,6 +15,16 @@
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#include <asm/irqflags.h>
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#include <linux/linkage.h>
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/* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
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#include <linux/elf-em.h>
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#define AUDIT_ARCH_I386 (EM_386|__AUDIT_ARCH_LE)
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#define __AUDIT_ARCH_LE 0x40000000
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#ifndef CONFIG_AUDITSYSCALL
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#define sysexit_audit int_ret_from_sys_call
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#define sysretl_audit int_ret_from_sys_call
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#endif
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#define IA32_NR_syscalls ((ia32_syscall_end - ia32_sys_call_table)/8)
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.macro IA32_ARG_FIXUP noebp=0
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@ -148,13 +158,15 @@ ENTRY(ia32_sysenter_target)
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ja ia32_badsys
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sysenter_do_call:
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IA32_ARG_FIXUP 1
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sysenter_dispatch:
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call *ia32_sys_call_table(,%rax,8)
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movq %rax,RAX-ARGOFFSET(%rsp)
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GET_THREAD_INFO(%r10)
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DISABLE_INTERRUPTS(CLBR_NONE)
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TRACE_IRQS_OFF
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testl $_TIF_ALLWORK_MASK,TI_flags(%r10)
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jnz int_ret_from_sys_call
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jnz sysexit_audit
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sysexit_from_sys_call:
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andl $~TS_COMPAT,TI_status(%r10)
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/* clear IF, that popfq doesn't enable interrupts early */
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andl $~0x200,EFLAGS-R11(%rsp)
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@ -170,9 +182,63 @@ sysenter_do_call:
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TRACE_IRQS_ON
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ENABLE_INTERRUPTS_SYSEXIT32
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sysenter_tracesys:
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#ifdef CONFIG_AUDITSYSCALL
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.macro auditsys_entry_common
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movl %esi,%r9d /* 6th arg: 4th syscall arg */
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movl %edx,%r8d /* 5th arg: 3rd syscall arg */
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/* (already in %ecx) 4th arg: 2nd syscall arg */
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movl %ebx,%edx /* 3rd arg: 1st syscall arg */
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movl %eax,%esi /* 2nd arg: syscall number */
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movl $AUDIT_ARCH_I386,%edi /* 1st arg: audit arch */
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call audit_syscall_entry
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movl RAX-ARGOFFSET(%rsp),%eax /* reload syscall number */
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cmpl $(IA32_NR_syscalls-1),%eax
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ja ia32_badsys
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movl %ebx,%edi /* reload 1st syscall arg */
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movl RCX-ARGOFFSET(%rsp),%esi /* reload 2nd syscall arg */
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movl RDX-ARGOFFSET(%rsp),%edx /* reload 3rd syscall arg */
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movl RSI-ARGOFFSET(%rsp),%ecx /* reload 4th syscall arg */
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movl RDI-ARGOFFSET(%rsp),%r8d /* reload 5th syscall arg */
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.endm
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.macro auditsys_exit exit
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testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),TI_flags(%r10)
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jnz int_ret_from_sys_call
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TRACE_IRQS_ON
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sti
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movl %eax,%esi /* second arg, syscall return value */
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cmpl $0,%eax /* is it < 0? */
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setl %al /* 1 if so, 0 if not */
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movzbl %al,%edi /* zero-extend that into %edi */
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inc %edi /* first arg, 0->1(AUDITSC_SUCCESS), 1->2(AUDITSC_FAILURE) */
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call audit_syscall_exit
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GET_THREAD_INFO(%r10)
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movl RAX-ARGOFFSET(%rsp),%eax /* reload syscall return value */
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movl RBP-ARGOFFSET(%rsp),%ebp /* reload user register value */
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movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi
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cli
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TRACE_IRQS_OFF
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testl %edi,TI_flags(%r10)
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jnz int_with_check
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jmp \exit
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.endm
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sysenter_auditsys:
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CFI_RESTORE_STATE
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auditsys_entry_common
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movl %ebp,%r9d /* reload 6th syscall arg */
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jmp sysenter_dispatch
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sysexit_audit:
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auditsys_exit sysexit_from_sys_call
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#endif
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sysenter_tracesys:
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xchgl %r9d,%ebp
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#ifdef CONFIG_AUDITSYSCALL
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testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%r10)
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jz sysenter_auditsys
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#endif
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SAVE_REST
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CLEAR_RREGS
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movq %r9,R9(%rsp)
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@ -252,13 +318,15 @@ cstar_do_call:
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cmpl $IA32_NR_syscalls-1,%eax
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ja ia32_badsys
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IA32_ARG_FIXUP 1
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cstar_dispatch:
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call *ia32_sys_call_table(,%rax,8)
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movq %rax,RAX-ARGOFFSET(%rsp)
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GET_THREAD_INFO(%r10)
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DISABLE_INTERRUPTS(CLBR_NONE)
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TRACE_IRQS_OFF
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testl $_TIF_ALLWORK_MASK,TI_flags(%r10)
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jnz int_ret_from_sys_call
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jnz sysretl_audit
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sysretl_from_sys_call:
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andl $~TS_COMPAT,TI_status(%r10)
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RESTORE_ARGS 1,-ARG_SKIP,1,1,1
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movl RIP-ARGOFFSET(%rsp),%ecx
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@ -270,8 +338,23 @@ cstar_do_call:
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CFI_RESTORE rsp
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USERGS_SYSRET32
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cstar_tracesys:
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#ifdef CONFIG_AUDITSYSCALL
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cstar_auditsys:
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CFI_RESTORE_STATE
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movl %r9d,R9-ARGOFFSET(%rsp) /* register to be clobbered by call */
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auditsys_entry_common
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movl R9-ARGOFFSET(%rsp),%r9d /* reload 6th syscall arg */
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jmp cstar_dispatch
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sysretl_audit:
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auditsys_exit sysretl_from_sys_call
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#endif
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cstar_tracesys:
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#ifdef CONFIG_AUDITSYSCALL
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testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%r10)
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jz cstar_auditsys
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#endif
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xchgl %r9d,%ebp
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SAVE_REST
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CLEAR_RREGS
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@ -492,6 +492,7 @@ tracesys:
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* Has correct top of stack, but partial stack frame.
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*/
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.globl int_ret_from_sys_call
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.globl int_with_check
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int_ret_from_sys_call:
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DISABLE_INTERRUPTS(CLBR_NONE)
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TRACE_IRQS_OFF
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