From d7bd7a8ae8cdb3f1414b1e032759d9ef324eb040 Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Wed, 15 Jul 2009 17:41:36 -0700 Subject: Secure AVX changes for auditing code. The original AVX patch used a function pointer to handle the difference between machines with and without AVX support. This is insecure. A well-placed memory exploit could lead to redirection of the execution. Using a variable and several tests is a bit slower but cannot be exploited in this way. --- sysdeps/x86_64/dl-trampoline.S | 327 +++++++++++++++++++++++++++++++++++++---- 1 file changed, 295 insertions(+), 32 deletions(-) (limited to 'sysdeps/x86_64/dl-trampoline.S') diff --git a/sysdeps/x86_64/dl-trampoline.S b/sysdeps/x86_64/dl-trampoline.S index f605351f30..2f55639662 100644 --- a/sysdeps/x86_64/dl-trampoline.S +++ b/sysdeps/x86_64/dl-trampoline.S @@ -96,9 +96,9 @@ _dl_runtime_profile: to detect if any xmm0-xmm7 registers are changed by audit module. */ subq $(LR_SIZE + XMM_SIZE*8), %rsp -#else +# else subq $LR_SIZE, %rsp # sizeof(La_x86_64_regs) -#endif +# endif movq %rsp, 24(%rbx) /* Fill the La_x86_64_regs structure. */ @@ -110,45 +110,308 @@ _dl_runtime_profile: movq %rdi, LR_RDI_OFFSET(%rsp) movq %rbp, LR_RBP_OFFSET(%rsp) + leaq 48(%rbx), %rax + movq %rax, LR_RSP_OFFSET(%rsp) + + /* We always store the XMM registers even if AVX is available. + This is to provide backward binary compatility for existing + audit modules. */ + movaps %xmm0, (LR_XMM_OFFSET)(%rsp) + movaps %xmm1, (LR_XMM_OFFSET + XMM_SIZE)(%rsp) + movaps %xmm2, (LR_XMM_OFFSET + XMM_SIZE*2)(%rsp) + movaps %xmm3, (LR_XMM_OFFSET + XMM_SIZE*3)(%rsp) + movaps %xmm4, (LR_XMM_OFFSET + XMM_SIZE*4)(%rsp) + movaps %xmm5, (LR_XMM_OFFSET + XMM_SIZE*5)(%rsp) + movaps %xmm6, (LR_XMM_OFFSET + XMM_SIZE*6)(%rsp) + movaps %xmm7, (LR_XMM_OFFSET + XMM_SIZE*7)(%rsp) + # ifdef HAVE_AVX_SUPPORT - jmp *L(save_and_restore_vector)(%rip) + .data +L(have_avx): + .zero 4 + .size L(have_avx), 4 + .previous - .align 16 -L(save_and_restore_vector_sse): + cmpl $0, L(have_avx)(%rip) + jne 1f + movq %rbx, %r11 # Save rbx + movl $1, %eax + cpuid + movq %r11,%rbx # Restore rbx + movl $1, %eax + testl $(1 << 28), %ecx + jne 2f + negl %eax +2: movl %eax, L(have_eax)(%rip) + cmpl $0, %eax + +1: js L(no_avx1) + + /* This is to support AVX audit modules. */ + vmovdqu %ymm0, (LR_VECTOR_OFFSET)(%rsp) + vmovdqu %ymm1, (LR_VECTOR_OFFSET + VECTOR_SIZE)(%rsp) + vmovdqu %ymm2, (LR_VECTOR_OFFSET + VECTOR_SIZE*2)(%rsp) + vmovdqu %ymm3, (LR_VECTOR_OFFSET + VECTOR_SIZE*3)(%rsp) + vmovdqu %ymm4, (LR_VECTOR_OFFSET + VECTOR_SIZE*4)(%rsp) + vmovdqu %ymm5, (LR_VECTOR_OFFSET + VECTOR_SIZE*5)(%rsp) + vmovdqu %ymm6, (LR_VECTOR_OFFSET + VECTOR_SIZE*6)(%rsp) + vmovdqu %ymm7, (LR_VECTOR_OFFSET + VECTOR_SIZE*7)(%rsp) + + /* Save xmm0-xmm7 registers to detect if any of them are + changed by audit module. */ + vmovdqa %xmm0, (LR_SIZE)(%rsp) + vmovdqa %xmm1, (LR_SIZE + XMM_SIZE)(%rsp) + vmovdqa %xmm2, (LR_SIZE + XMM_SIZE*2)(%rsp) + vmovdqa %xmm3, (LR_SIZE + XMM_SIZE*3)(%rsp) + vmovdqa %xmm4, (LR_SIZE + XMM_SIZE*4)(%rsp) + vmovdqa %xmm5, (LR_SIZE + XMM_SIZE*5)(%rsp) + vmovdqa %xmm6, (LR_SIZE + XMM_SIZE*6)(%rsp) + vmovdqa %xmm7, (LR_SIZE + XMM_SIZE*7)(%rsp) + +L(no_avx1): # endif -# define MOVXMM movaps -# include "dl-trampoline.h" + movq %rsp, %rcx # La_x86_64_regs pointer to %rcx. + movq 48(%rbx), %rdx # Load return address if needed. + movq 40(%rbx), %rsi # Copy args pushed by PLT in register. + movq 32(%rbx), %rdi # %rdi: link_map, %rsi: reloc_index + leaq 16(%rbx), %r8 + call _dl_profile_fixup # Call resolver. + + movq %rax, %r11 # Save return value. + + movq 8(%rbx), %rax # Get back register content. + movq LR_RDX_OFFSET(%rsp), %rdx + movq LR_R8_OFFSET(%rsp), %r8 + movq LR_R9_OFFSET(%rsp), %r9 # ifdef HAVE_AVX_SUPPORT -# undef MOVXMM -# define MOVXMM vmovdqa -# define RESTORE_AVX - .align 16 -L(save_and_restore_vector_avx): -# include "dl-trampoline.h" + cmpl $0, L(have_avx)(%rip) + js L(no_avx2) + + /* Check if any xmm0-xmm7 registers are changed by audit + module. */ + vmovdqa (LR_XMM_OFFSET)(%rsp), %xmm0 + vpcmpeqq (LR_SIZE)(%rsp), %xmm0, %xmm1 + vpmovmskb %xmm1, %esi + cmpl $0xffff, %esi + je 1f + vmovdqu (LR_VECTOR_OFFSET)(%rsp), %ymm0 + +1: vmovdqa (LR_XMM_OFFSET + XMM_SIZE)(%rsp), %xmm1 + vpcmpeqq (LR_SIZE + XMM_SIZE)(%rsp), %xmm1, %xmm2 + vpmovmskb %xmm2, %esi + cmpl $0xffff, %esi + je 1f + vmovdqu (LR_VECTOR_OFFSET + VECTOR_SIZE)(%rsp), %ymm1 + +1: vmovdqa (LR_XMM_OFFSET + XMM_SIZE*2)(%rsp), %xmm2 + vpcmpeqq (LR_SIZE + XMM_SIZE*2)(%rsp), %xmm2, %xmm3 + vpmovmskb %xmm3, %esi + cmpl $0xffff, %esi + je 1f + vmovdqu (LR_VECTOR_OFFSET + VECTOR_SIZE*2)(%rsp), %ymm2 + +1: vmovdqa (LR_XMM_OFFSET + XMM_SIZE*3)(%rsp), %xmm3 + vpcmpeqq (LR_SIZE + XMM_SIZE*3)(%rsp), %xmm3, %xmm4 + vpmovmskb %xmm4, %esi + cmpl $0xffff, %esi + je 1f + vmovdqu (LR_VECTOR_OFFSET + VECTOR_SIZE*3)(%rsp), %ymm3 + +1: vmovdqa (LR_XMM_OFFSET + XMM_SIZE*4)(%rsp), %xmm4 + vpcmpeqq (LR_SIZE + XMM_SIZE*4)(%rsp), %xmm4, %xmm5 + vpmovmskb %xmm5, %esi + cmpl $0xffff, %esi + je 1f + vmovdqu (LR_VECTOR_OFFSET + VECTOR_SIZE*4)(%rsp), %ymm4 + +1: vmovdqa (LR_XMM_OFFSET + XMM_SIZE*5)(%rsp), %xmm5 + vpcmpeqq (LR_SIZE + XMM_SIZE*5)(%rsp), %xmm5, %xmm6 + vpmovmskb %xmm6, %esi + cmpl $0xffff, %esi + je 1f + vmovdqu (LR_VECTOR_OFFSET + VECTOR_SIZE*5)(%rsp), %ymm5 + +1: vmovdqa (LR_XMM_OFFSET + XMM_SIZE*6)(%rsp), %xmm6 + vpcmpeqq (LR_SIZE + XMM_SIZE*6)(%rsp), %xmm6, %xmm7 + vpmovmskb %xmm7, %esi + cmpl $0xffff, %esi + je 1f + vmovdqu (LR_VECTOR_OFFSET + VECTOR_SIZE*6)(%rsp), %ymm6 + +1: vmovdqa (LR_XMM_OFFSET + XMM_SIZE*7)(%rsp), %xmm7 + vpcmpeqq (LR_SIZE + XMM_SIZE*7)(%rsp), %xmm7, %xmm8 + vpmovmskb %xmm8, %esi + cmpl $0xffff, %esi + je 1f + vmovdqu (LR_VECTOR_OFFSET + VECTOR_SIZE*7)(%rsp), %ymm7 + jmp 1f + +L(no_avx2): + vmovdqa (LR_XMM_OFFSET)(%rsp), %xmm0 + vmovdqa (LR_XMM_OFFSET + XMM_SIZE)(%rsp), %xmm1 + vmovdqa (LR_XMM_OFFSET + XMM_SIZE*2)(%rsp), %xmm2 + vmovdqa (LR_XMM_OFFSET + XMM_SIZE*3)(%rsp), %xmm3 + vmovdqa (LR_XMM_OFFSET + XMM_SIZE*4)(%rsp), %xmm4 + vmovdqa (LR_XMM_OFFSET + XMM_SIZE*5)(%rsp), %xmm5 + vmovdqa (LR_XMM_OFFSET + XMM_SIZE*6)(%rsp), %xmm6 + vmovdqa (LR_XMM_OFFSET + XMM_SIZE*7)(%rsp), %xmm7 + +1: +# else + movaps (LR_XMM_OFFSET)(%rsp), %xmm0 + movaps (LR_XMM_OFFSET + XMM_SIZE)(%rsp), %xmm1 + movaps (LR_XMM_OFFSET + XMM_SIZE*2)(%rsp), %xmm2 + movaps (LR_XMM_OFFSET + XMM_SIZE*3)(%rsp), %xmm3 + movaps (LR_XMM_OFFSET + XMM_SIZE*4)(%rsp), %xmm4 + movaps (LR_XMM_OFFSET + XMM_SIZE*5)(%rsp), %xmm5 + movaps (LR_XMM_OFFSET + XMM_SIZE*6)(%rsp), %xmm6 + movaps (LR_XMM_OFFSET + XMM_SIZE*7)(%rsp), %xmm7 # endif - cfi_endproc - .size _dl_runtime_profile, .-_dl_runtime_profile + movq 16(%rbx), %r10 # Anything in framesize? + testq %r10, %r10 + jns 3f + + /* There's nothing in the frame size, so there + will be no call to the _dl_call_pltexit. */ + + /* Get back registers content. */ + movq LR_RCX_OFFSET(%rsp), %rcx + movq LR_RSI_OFFSET(%rsp), %rsi + movq LR_RDI_OFFSET(%rsp), %rdi + movq %rbx, %rsp + movq (%rsp), %rbx + cfi_restore(rbx) + cfi_def_cfa_register(%rsp) + + addq $48, %rsp # Adjust the stack to the return value + # (eats the reloc index and link_map) + cfi_adjust_cfa_offset(-48) + jmp *%r11 # Jump to function address. + +3: + cfi_adjust_cfa_offset(48) + cfi_rel_offset(%rbx, 0) + cfi_def_cfa_register(%rbx) + + /* At this point we need to prepare new stack for the function + which has to be called. We copy the original stack to a + temporary buffer of the size specified by the 'framesize' + returned from _dl_profile_fixup */ + + leaq LR_RSP_OFFSET(%rbx), %rsi # stack + addq $8, %r10 + andq $0xfffffffffffffff0, %r10 + movq %r10, %rcx + subq %r10, %rsp + movq %rsp, %rdi + shrq $3, %rcx + rep + movsq + + movq 24(%rdi), %rcx # Get back register content. + movq 32(%rdi), %rsi + movq 40(%rdi), %rdi + + call *%r11 + + mov 24(%rbx), %rsp # Drop the copied stack content + + /* Now we have to prepare the La_x86_64_retval structure for the + _dl_call_pltexit. The La_x86_64_regs is being pointed by rsp now, + so we just need to allocate the sizeof(La_x86_64_retval) space on + the stack, since the alignment has already been taken care of. */ # ifdef HAVE_AVX_SUPPORT -L(check_avx): - mov %rbx,%r11 # Save rbx - movl $1, %eax - cpuid - mov %r11,%rbx # Restore rbx - leaq L(save_and_restore_vector_sse)(%rip), %rax - andl $(1 << 28), %ecx # Check if AVX is available. - jz L(ret) - leaq L(save_and_restore_vector_avx)(%rip), %rax -L(ret): - movq %rax,L(save_and_restore_vector)(%rip) - jmp *%rax - - .section .data.rel.local,"aw",@progbits - .align 8 -L(save_and_restore_vector): - .quad L(check_avx) + /* sizeof(La_x86_64_retval). Need extra space for 2 SSE + registers to detect if xmm0/xmm1 registers are changed + by audit module. */ + subq $(LRV_SIZE + XMM_SIZE*2), %rsp +# else + subq $LRV_SIZE, %rsp # sizeof(La_x86_64_retval) +# endif + movq %rsp, %rcx # La_x86_64_retval argument to %rcx. + + /* Fill in the La_x86_64_retval structure. */ + movq %rax, LRV_RAX_OFFSET(%rcx) + movq %rdx, LRV_RDX_OFFSET(%rcx) + + movaps %xmm0, LRV_XMM0_OFFSET(%rcx) + movaps %xmm1, LRV_XMM1_OFFSET(%rcx) + +# ifdef HAVE_AVX_SUPPORT + cmpl $0, L(have_avx)(%rip) + js L(no_avx3) + + /* This is to support AVX audit modules. */ + vmovdqu %ymm0, LRV_VECTOR0_OFFSET(%rcx) + vmovdqu %ymm1, LRV_VECTOR1_OFFSET(%rcx) + + /* Save xmm0/xmm1 registers to detect if they are changed + by audit module. */ + vmovdqa %xmm0, (LRV_SIZE)(%rcx) + vmovdqa %xmm1, (LRV_SIZE + XMM_SIZE)(%rcx) + +L(no_avx3): # endif + + fstpt LRV_ST0_OFFSET(%rcx) + fstpt LRV_ST1_OFFSET(%rcx) + + movq 24(%rbx), %rdx # La_x86_64_regs argument to %rdx. + movq 40(%rbx), %rsi # Copy args pushed by PLT in register. + movq 32(%rbx), %rdi # %rdi: link_map, %rsi: reloc_index + call _dl_call_pltexit + + /* Restore return registers. */ + movq LRV_RAX_OFFSET(%rsp), %rax + movq LRV_RDX_OFFSET(%rsp), %rdx + +# ifdef HAVE_AVX_SUPPORT + cmpl $0, L(have_avx)(%rip) + js L(no_avx4) + + /* Check if xmm0/xmm1 registers are changed by audit module. */ + vmovdqa LRV_XMM0_OFFSET(%rsp), %xmm0 + vpcmpeqq (LRV_SIZE)(%rsp), %xmm0, %xmm1 + vpmovmskb %xmm1, %esi + cmpl $0xffff, %esi + je 1f + vmovdqu LRV_VECTOR0_OFFSET(%rsp), %ymm0 + +1: vmovdqa LRV_XMM1_OFFSET(%rsp), %xmm1 + vpcmpeqq (LRV_SIZE + XMM_SIZE)(%rsp), %xmm1, %xmm2 + vpmovmskb %xmm2, %esi + cmpl $0xffff, %esi + je 1f + vmovdqu LRV_VECTOR1_OFFSET(%rsp), %ymm1 + jmp 1f + +L(no_avx4): + vmovdqa LRV_XMM0_OFFSET(%rsp), %xmm0 + vmovdqa LRV_XMM1_OFFSET(%rsp), %xmm1 + +1: +# else + movaps LRV_XMM0_OFFSET(%rsp), %xmm0 + movaps LRV_XMM1_OFFSET(%rsp), %xmm1 +# endif + + fldt LRV_ST1_OFFSET(%rsp) + fldt LRV_ST0_OFFSET(%rsp) + + movq %rbx, %rsp + movq (%rsp), %rbx + cfi_restore(rbx) + cfi_def_cfa_register(%rsp) + + addq $48, %rsp # Adjust the stack to the return value + # (eats the reloc index and link_map) + cfi_adjust_cfa_offset(-48) + retq + + cfi_endproc + .size _dl_runtime_profile, .-_dl_runtime_profile #endif -- cgit 1.4.1