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check arguments, return error instead of raising exceptions. (#1125)

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* check arguments, return error instaed of raising exceptions. close #1117.

* remove empty lines. remove thr underscore prefix in function name.
This commit is contained in:
Chen Huitao
2019-08-23 17:05:14 +08:00
committed by Nguyen Anh Quynh
parent bc572be472
commit 23a426625f
4 changed files with 119 additions and 3 deletions
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78
qemu/target-i386/seg_helper.c
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@@ -1539,6 +1539,84 @@ void helper_ltr(CPUX86State *env, int selector)
env->tr.selector = selector;
}
// Unicorn: check the arguments before run cpu_x86_load_seg().
int uc_check_cpu_x86_load_seg(CPUX86State *env, int seg_reg, int sel)
{
int selector;
uint32_t e2;
int cpl, dpl, rpl;
SegmentCache *dt;
int index;
target_ulong ptr;
if (!(env->cr[0] & CR0_PE_MASK) || (env->eflags & VM_MASK)) {
return 0;
} else {
selector = sel & 0xffff;
cpl = env->hflags & HF_CPL_MASK;
if ((selector & 0xfffc) == 0) {
/* null selector case */
if (seg_reg == R_SS
#ifdef TARGET_X86_64
&& (!(env->hflags & HF_CS64_MASK) || cpl == 3)
#endif
) {
return UC_ERR_EXCEPTION;
}
return 0;
} else {
if (selector & 0x4) {
dt = &env->ldt;
} else {
dt = &env->gdt;
}
index = selector & ~7;
if ((index + 7) > dt->limit) {
return UC_ERR_EXCEPTION;
}
ptr = dt->base + index;
e2 = cpu_ldl_kernel(env, ptr + 4);
if (!(e2 & DESC_S_MASK)) {
return UC_ERR_EXCEPTION;
}
rpl = selector & 3;
dpl = (e2 >> DESC_DPL_SHIFT) & 3;
if (seg_reg == R_SS) {
/* must be writable segment */
if ((e2 & DESC_CS_MASK) || !(e2 & DESC_W_MASK)) {
return UC_ERR_EXCEPTION;
}
if (rpl != cpl || dpl != cpl) {
return UC_ERR_EXCEPTION;
}
} else {
/* must be readable segment */
if ((e2 & (DESC_CS_MASK | DESC_R_MASK)) == DESC_CS_MASK) {
return UC_ERR_EXCEPTION;
}
if (!(e2 & DESC_CS_MASK) || !(e2 & DESC_C_MASK)) {
/* if not conforming code, test rights */
if (dpl < cpl || dpl < rpl) {
return UC_ERR_EXCEPTION;
}
}
}
if (!(e2 & DESC_P_MASK)) {
if (seg_reg == R_SS) {
return UC_ERR_EXCEPTION;
} else {
return UC_ERR_EXCEPTION;
}
}
}
}
return 0;
}
/* only works if protected mode and not VM86. seg_reg must be != R_CS */
void helper_load_seg(CPUX86State *env, int seg_reg, int selector)
{