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Avoid jumping to Rust code with user %rsp (reentry_panic)

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This commit is contained in:
Jethro Beekman 2020-02-10 21:00:22 +01:00
parent 236ab6e6d6
commit 71b9ed4a36
1 changed files with 6 additions and 7 deletions
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13
src/libstd/sys/sgx/abi/entry.S
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@ -144,13 +144,15 @@ elf_entry:
/* This code needs to be called *after* the enclave stack has been setup. */ /* This code needs to be called *after* the enclave stack has been setup. */
/* There are 3 places where this needs to happen, so this is put in a macro. */ /* There are 3 places where this needs to happen, so this is put in a macro. */
.macro sanitize_rflags .macro entry_sanitize_final
/* Sanitize rflags received from user */ /* Sanitize rflags received from user */
/* - DF flag: x86-64 ABI requires DF to be unset at function entry/exit */ /* - DF flag: x86-64 ABI requires DF to be unset at function entry/exit */
/* - AC flag: AEX on misaligned memory accesses leaks side channel info */ /* - AC flag: AEX on misaligned memory accesses leaks side channel info */
pushfq pushfq
andq $~0x40400, (%rsp) andq $~0x40400, (%rsp)
popfq popfq
bt $0,.Laborted(%rip)
jc .Lreentry_panic
.endm .endm
.text .text
@ -174,9 +176,6 @@ sgx_entry:
jz .Lskip_debug_init jz .Lskip_debug_init
mov %r10,%gs:tcsls_debug_panic_buf_ptr mov %r10,%gs:tcsls_debug_panic_buf_ptr
.Lskip_debug_init: .Lskip_debug_init:
/* check for abort */
bt $0,.Laborted(%rip)
jc .Lreentry_panic
/* check if returning from usercall */ /* check if returning from usercall */
mov %gs:tcsls_last_rsp,%r11 mov %gs:tcsls_last_rsp,%r11
test %r11,%r11 test %r11,%r11
@ -194,7 +193,7 @@ sgx_entry:
lea IMAGE_BASE(%rip),%rax lea IMAGE_BASE(%rip),%rax
add %rax,%rsp add %rax,%rsp
mov %rsp,%gs:tcsls_tos mov %rsp,%gs:tcsls_tos
sanitize_rflags entry_sanitize_final
/* call tcs_init */ /* call tcs_init */
/* store caller-saved registers in callee-saved registers */ /* store caller-saved registers in callee-saved registers */
mov %rdi,%rbx mov %rdi,%rbx
@ -212,7 +211,7 @@ sgx_entry:
mov %r15,%r9 mov %r15,%r9
jmp .Lafter_init jmp .Lafter_init
.Lskip_init: .Lskip_init:
sanitize_rflags entry_sanitize_final
.Lafter_init: .Lafter_init:
/* call into main entry point */ /* call into main entry point */
load_tcsls_flag_secondary_bool cx /* RCX = entry() argument: secondary: bool */ load_tcsls_flag_secondary_bool cx /* RCX = entry() argument: secondary: bool */
@ -311,10 +310,10 @@ usercall:
movq $0,%gs:tcsls_last_rsp movq $0,%gs:tcsls_last_rsp
/* restore callee-saved state, cf. "save" above */ /* restore callee-saved state, cf. "save" above */
mov %r11,%rsp mov %r11,%rsp
sanitize_rflags
ldmxcsr (%rsp) ldmxcsr (%rsp)
fldcw 4(%rsp) fldcw 4(%rsp)
add $8, %rsp add $8, %rsp
entry_sanitize_final
pop %rbx pop %rbx
pop %rbp pop %rbp
pop %r12 pop %r12